From The History of Philosophy: A Short Survey


James Fieser


Revised 6/1/2020




A. Introduction

B. Locke

No Innate Ideas

Simple and Complex Ideas

Primary and Secondary Qualities

Natural Rights and Revolution

C. Berkeley

Idealism: No Materials Objects

Arguments against Material Objects

God and Evil

D. Hume

Origin and Association of Ideas

Personal Identity and Causality

Belief in Miracles

Morality: Reason vs. Emotion

Radical Skepticism and Natural Belief

Reading 1: Locke against Innate Ideas (Essay 1.2)

Reading 2: Berkeley against Material Objects (Three Dialogues, 1 and 2)

Reading 3: Hume against a Continuous Self (Treatise, 1.4.6)

Study Questions




During the seventeenth and eighteenth-centuries, Britain certainly had its fair share of rationalist philosophers, particularly of the Platonist variety. However, Britain’s philosophy was soon dominated by an alternative and more scientific view that knowledge is gained primarily or mainly through the five senses. We see this presumption in Francis Bacon’s statement that in our efforts to understand nature we can “can act and understand no further than [we have] . . .  observed in either the operation or the contemplation of the method and order of nature” (New Organon, 1.1). Direct experience is foundational for obtaining knowledge, and this position is known as empiricism. During the first half of the 18th century, three great philosophers—Locke, Berkeley and Hume—argued for this approach, thus forming a philosophical movement known as British empiricism. Contrary to the 17th century rationalist philosophers in Continental Europe, these British empiricists largely denied the role of innate ideas and deduction in the quest for knowledge. Instead, they argued, knowledge comes from sensory experience and inductive reasoning.




The originator of British empiricism was John Locke (1632–1704), who was born into a Puritan family near Bristol, England, his father being an attorney and government official. He studied at Oxford University and later worked there in various positions, where he took particular interest in the writings of Descartes and other modern thinkers. The direction of Locke’s life shifted dramatically when he accepted employment as the household physician of a prominent British politician who founded the radical Whig party, which opposed the absolute rule of the British monarchy. As public opposition to the King was on the increase during this period, Locke’s association with the Whigs forced him to flee to the Netherlands for his safety. He returned home after the King was overthrown in the Glorious Revolution of 1688, and subsequently published a steady stream of books that he had been working on for some time. The books were instant sensations, and his reputation skyrocketed, rivaling that of Newton. He died at age 72, never having married or produced children. Locke wrote on a range of subjects, including politics, religion, economics and education. His fame as a philosopher, though, rests on his work in two distinct areas. First, as a metaphysical philosopher he expounded the empiricist position that there are no innate ideas and all knowledge comes from experience. He sets this out in his Essay Concerning Human Understanding (1689). Second, as a political philosopher he developed the notion of natural rights in his Two Treatises of Government (1690). We will look at each of these.


No Innate Ideas

Throughout the history of philosophy it was common to hold that human beings are born with a special set of ideas—innate ideas—that guide us in our quest for truth and certainty. In ancient times Plato held that we have an inborn knowledge of the perfect Forms of justice, piety, goodness, and countless others. In the Renaissance John Calvin held that we are all born with a sense of God. Descartes, the leading Continental rationalist, held that we have an innate idea of ourselves and of infinite perfection. When looking at this long history of belief in innate ideas, Locke said that enough was enough, and he launched a powerful attack on the very concept. For Locke, we simply have no innate ideas, and all notions that we have come to us through experience. It’s important to recognize that Locke was not critical of other types of innate human characteristics, such as coughing or blinking, which are inborn muscle reflexes. His attack focuses exclusively on the ideas that we are born with. The movie “Close Encounters of a Third Kind” illustrates the features of an innate idea. The lead character has an idea of a mountain embedded in his mind by some aliens from outer space. The idea obsesses him to the point that one evening at the supper table he scoops a pile of mashed potatoes onto his plate and then shapes it into the image he has of the mountain.

             While Locke’s attack on innate ideas certainly applies to the views of Descartes and other Continental rationalists, they were not his immediate target. Instead, according to Locke, there are two types of innate ideas that philosophers commonly allege: speculative ones and practical ones. Good examples of speculative innate ideas, he argues, are the foundational logical concepts that are sometimes dubbed “laws of thought” and associated with Aristotle. Chief among these is the law of identity which simply states that an object is the same as itself, or, in more formal terms, A=A. The chair in front of me is identical to the chair in front of me. The tree in the yard is identical to the tree in the yard. While this seems to be a painfully obvious truth, it does play an important role in logical systems. Next, there is the law of non-contradiction, which Aristotle himself states as follows: “It is impossible for the same thing to belong and not to belong at the same time to the same thing and in the same respect” (Metaphysics, 4.3). The point can be stated more formally as “not (P and not P)”, that is, it is not the case that P and its opposite not-P obtain at the same time. It is impossible for the chair in front of me to exist and not exist at the same time. It is impossible for the apple on the table to be completely red and not completely red at the same time.

             The second type of alleged innate idea involves practical ones, that is, ideas that regulate moral behavioral practices. Examples of these, according to Locke, are the famous “five common notions” of religion and morality proposed by British philosopher Edward Herbert (1583-1648). They are (1) There exists a supreme God, (2) We should worship God, (3) The best form of worship is proper moral behavior, (4) We should repent for our immoral conduct, (5) We will be rewarded or punished in the afterlife for our conduct on earth. Herbert argued that all humans have an inborn knowledge of these truths and we find these truths exhibited in virtually all religions around the world.

             Locke has two main arguments against the innateness of ideas, both speculative and practical. First, he argues, people in fact do not universally hold to these ideas, contrary to what defenders of innate ideas typically claim. This is particularly obvious with the laws of thought, which children and mentally challenged people have no conception of whatsoever:


If therefore children and idiots have souls, have minds, with those impressions upon them, they must unavoidably perceive them, and necessarily know and assent to these truths. Which since they do not, it is evident that there are no such impressions. For if they are not notions naturally imprinted, how can they be innate? and if they are notions imprinted, how can they be unknown? To say a notion is imprinted on the mind, and yet at the same time to say, that the mind is ignorant of it, and never yet took notice of it, is to make this impression nothing. [Essay, 1.2.12]


Locke’s second argument is that it makes no sense to hold that such ideas lie dormant within us, and then blossom when we reach the right age, contrary to what defenders of innate ideas commonly claim. Again, particularly with the laws of thought, children reason perfectly well regarding identity and non-contradiction, yet at the same time are completely incapable of articulating those specific ideas. If these ideas really were innate, then children should be able to verbally express them. As Locke states it, “How many instances of the use of reason may we observe in children, a long time before they have any knowledge of this maxim, ‘That it is impossible for the same thing to be and not to be?’” (ibid). Also, it is obvious that may adults have reached the so-called age of reason, such as the illiterate and those from primitive societies, and yet lack these ideas. These people “pass many years, even of their rational age, without ever thinking on this and the like general propositions.”


Simple and Complex Ideas

According to Locke, then, we should completely reject the theory of innate ideas and instead look for the true source of our ideas within human experience. His basic position, which encapsulates the entire empiricist approach, is that the mind is from birth a blank slate (or sheet of “white paper” in his words), which gets filled with information through experience. However, the process by which we form our ideas through experience has two main steps. We first acquire simple ideas through experience, and then recombine those simple ideas in different ways to create more complex ideas.

             Simple ideas are the building blocks from which all other ideas are formed, and, for Locke, there are two main sources of simple ideas. The first and most obvious source is that they come from sensation, specifically our five senses which give us perceptions of colors, tastes, smells, tactile solidity. The color of blue, the taste of sweetness, the tactile sensation of smoothness, the sound of a high-pitched squeak are all basic sensory experiences that are building bocks for our ideas about the external world. Second, there are simple ideas that come to us through reflecting on our mental processes; these are ideas of reflection, or “introspection” as we now call them. I can shut my eyes and think about how my mind operates: how I perceive things through my senses, how I think about problems, how I doubt questionable ideas, how I believe reasonable ideas, how I will to perform actions. According to Locke, “This source of ideas every man has wholly in himself; and though it be not sense, as having nothing to do with external objects, yet it is very like it, and might properly enough be called internal sense” (ibid, 2.1.3).

             According to Locke, some of our simple ideas come solely through sensation without any introspective reflection, such as our perceptions of colors, sounds and smells. Others come solely through introspective reflection, such as our notions of perceptions of the mental acts of thinking and willing. Nothing that we perceive through our five senses will give us ideas of these. Then there is an especially interesting group of simple ideas that we can get either through sensation or introspective reflection. Pleasure and pain is a good example. I can feel physical pain through my senses as when a candle flame burns me; but I can also experience emotional pain in my mind when a loved one dies. Another example is the notion of causal force, or “power” as 18th century philosophers called it. Through my senses, I see a volcano spew out lava with great causal force. But through introspective reflection I can also experience causal force when I reflect on my own willful decisions, such as when I will to conjure up in my mind the idea of a rock, a tree or a unicorn. My will itself is a causal power. Other ideas that we get through both sensation and reflection are existence, unity, and succession.

             For Locke, there are countless simple perceptions that flood into our minds through sensation and reflection, in fact so many that we don’t even have names for most of them. But as we store these raw simple notions in our memories, our minds mechanically shuffle them around and create new ones which he calls complex ideas. There are three specific mental processes that form complex ideas. First, some are the result of simply combining together more simple ideas. For example, I can get a complex idea of an apple by assembling the simple ideas of roundness, redness, sweetness, and moistness. Second, some complex ideas involve relations that we get from comparing two things, such as the notions of “larger” and “smaller” that I get when comparing two apples of different sizes. Third, there are complex ideas that result from the mental process of abstraction, such as when I arrive at the abstract notion of “roundness” by looking at an apple and stripping away all of its attributes except for its being round. As the mind then churns out complex ideas from simple ones, the complex ideas will be of two types: ideas of substances and ideas of modes. Ideas of substances are those of individual objects such as such as rocks, trees, houses, animals, people and God. Ideas of modes are attributes of those objects that cannot exist independently of them, such as an apple’s attributes of being round, crunchy and moist.


Primary and Secondary Qualities

One of Locke’s philosophical claims to fame is his development of the distinction between primary and secondary qualities of objects. The issue involves a distinction between qualities of objects that actually belong to the object itself, and qualities of objects that we impose on them. Suppose, for example, that I made a list of the qualities that I perceive in an apple. It has a round shape, red surface, smooth texture, and a sweet taste. It also has a particular size and weight. Some of these qualities are part of the object itself, and others are qualities that I am imposing on the apple. For Locke, a primary quality is an attribute of that is inseparable for a physical body, and includes solidity, shape, motion, number. These are components that an object retains, regardless of how we might modify the object, such as by cutting it into pieces. He illustrates this by considering changes that we might impose on a grain of wheat:


Take a grain of wheat, divide it into two parts; each part has still solidity, extension, figure, and mobility: divide it again, and it retains still the same qualities; and so divide it on, till the parts become insensible; they must retain still each of them all those qualities. For division (which is all that a mill, or pestle, or any other body, does upon another, in reducing it to insensible parts) can never take away either solidity, extension, figure, or mobility from any body, but only makes two or more distinct separate masses of matter, of that which was but one before; all which distinct masses, reckoned as so many distinct bodies, after division, make a certain number. [Ibid, 2.8.9]


No matter how much we grind down the grain of wheat, the parts still retain the qualities of solidity and shape which were inherent in the original grain.

             In contrast with primary qualities, there are also secondary qualities that are spectator-dependent: we impose the attributes onto objects, and these include colors, sounds, and tastes. For example, there is something in the apple that makes it appear red to me, but the redness itself does not reside within the apple but instead is a function of my sense organs and biology. The phenomenon of colorblindness is ample proof of this: while the structure of the apple itself might trigger the perception of redness in my mind, I need to have the appropriately designed eyes to have that perception. So too with other qualities of the apple like taste and smell: the specific sensations of taste and smell directly depend upon the construction of my tongue and nose.

             Locke adds there is a third type of quality of objects—tertiary qualities—which involves the power that an object has to produce new ideas or sensations in us. For example, the mere sight of an apple may produce a feeling of hunger within me. Being near a fire may produce a feeling of warmth within me. Perhaps the main difference between secondary and tertiary qualities is that with secondary ones we often improperly mistake them for primary attributes of the objects themselves. For example, I might just assume that an apple’s redness is actually part of the apple when, upon reflection, I would see that it clearly isn’t. With tertiary qualities, though, we are less apt to make this mistake; for example, I would never presume that my feeling of hunger resides in the apple itself. Aesthetic feelings, such as the sense of beauty I get when viewing a landscape, might also be included among tertiary qualities.


Natural Rights and Revolution

Locke’s empiricist views immediately impacted the direction of philosophy for generations to come, particularly in Great Britain. As influential as Locke was in this regard, however, his impact was even greater with his political philosophy. Even today, people around the world are familiar with the idea that the function of governments is to protect our freedoms, and citizens are morally entitled to overthrow governments when they fail to perform that task. This was Locke’s great political contribution to the civilized world. Prior to Locke, the standard view of political authority was a position called the “divine right of kings.” That is, political rulers are put in power by God, and, as God’s representatives on earth, we can never challenge their authority over us. Locke was strongly opposed to this notion, in part because of his personal experience in England where the people recently overthrew their despotic king. Locke supported the overthrow and composed his Two Treatises of Government (1690) to justify rebellion against bad rulers.

             The starting point for Locke’s theory is the state of nature, that is, the condition that humans were in prior to the creation of societies and governments. Thomas Hobbes, we’ve seen, believed that the state of nature is a place of moral chaos, where might makes right, and everyone is perpetually at war with everyone else to gain the upper hand. Locke, though, is a little more optimistic than Hobbes. Yes, the state of nature sometimes can be brutal, but there still are moral rules that everyone must follow. For Locke, everyone is born with fundamental God-given rights and, even without governments, we have a moral obligation to respect each other’s rights. The four main natural rights are those of life, health, liberty and possessions:


The state of nature has a law of nature to govern it, which obliges every one: and reason, which is that law, teaches all mankind, who will but consult it, that being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions. [Two Treatises, 2.6]


What if someone does violate my rights by mugging me and taking my wallet, for example? Locke’s answer is that I am entitled to punish the mugger: “every one has a right to punish the transgressors of that law to such a degree, as may hinder its violation” (ibid, 2.7). By violating my rights, the mugger has thereby forfeited all of his own rights, including his right to life, and at that point I am fully entitled to hunt him down, punish him, and even kill him as I see fit. The reason for such a harsh reprisal is that, when the mugger attacks me he puts me in a position where I’m fully under his control, and, even if he doesn’t kill me, I have every reason to assume that he might. The mugger has thus declared war on me and, at that point, I have the right to punish him by any means whatsoever.

             While in the state of nature, vigilante justice is the only recourse we have to retaliate against attackers. Once we create a civil society with a government, however, all that changes. Following Hobbes, Locke argues that we create societies by forming a social contract with each other: we agree to mutually set aside our hostilities in the name of preserving peace. And, to assure that we all follow the rules, we set up a government that has the authority to punish anyone who breaks the rules and thereby violates our basic rights. The whole point of establishing societies and governments to begin with is to preserve our natural rights, particularly, Locke argues, our right to possessions:


The reason why men enter into society, is the preservation of their property. And the end why they choose and authorize a legislative, is, that there may be laws made, and rules set, as guards and fences to the properties of all the members of the society, to limit the power, and moderate the dominion, of every part and member of the society. [ibid, 222]


             What happens, though, when governments fail at their assigned task, and, rather than protecting our rights they undermine them? Locke specifically has in mind a situation in which the government unjustly takes people’s property and reduces them to “slavery under arbitrary power” (ibid, 222). His answer is that we are thrown back into a state of war, this time a war with our government. By violating our rights, the government has forfeited its authority over us, and we are fully entitled to remove the offending government and set up a better one:


by this breach of trust they forfeit the power the people had put into their hands for quite contrary ends, and it devolves to the people, who have a right to resume their original liberty, and, by the establishment of a new legislative, (such as they shall think fit) provide for their own safety and security, which is the end for which they are in society. [Ibid, 222]


As necessary as governments are for assuring that individual citizens respect each others’ rights, the government itself has a responsibility to uphold its part of the social contract; if it fails in that regard, society is entitled to do what’s necessary to remove it—even start a full-fledged revolution. If it comes to that, according to Locke, the blame lies with the government, not with the revolutionaries.

             Locke’s justification for revolution was quite radical in his time, especially when other philosophers were arguing that governments have absolute authority over citizens through a divine right of kings, and can never be overthrown. Within a matter of decades, Locke’s rationale was adopted by revolutionary movements in both America and France, as we see specifically in this famous opening to the U.S. Declaration of Independence, penned by Thomas Jefferson:


We hold these truths to be self-evident, that all men are created equal, that they are endowed by their creator with certain unalienable rights, that among these are life, liberty and the pursuit of happiness.—That to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed,—that whenever any form of government becomes destructive of these ends, it is the right of the people to alter or to abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness.


Locke, we’ve seen, stressed that revolution is justified particularly when governments violate our property rights. Jefferson, though, deemphasizes our property rights and implies that the governmental violation of any of our fundamental natural rights may justify revolution.




The second major figure in British Empiricism was George Berkeley (1685-1753). Born into a moderately wealthy family near Kilkenny, Ireland, his father was a customs officer who migrated there from England. Berkeley received his B.A. and M.A. degrees from Trinity College, Dublin, and taught there for some years. Still in his twenties he, he wrote his two main philosophical works, upon which his fame today rests: A Treatise concerning the Principles of Human Knowledge (1710) and Three Dialogues between Hylas and Philonous (1713). In his thirties he was ordained into the Anglican Church of Ireland and received is Doctor of Divinity degree. Shortly after, he devised a plan to establish a college in the Bermuda Islands to train ministers and missionaries for the colonies. He traveled to Rhode Island to prepare for the project, but after three years abandoned it when governmental funding for it never came through. He then donated land and books to the newly founded Yale College and returned to Ireland. Back home he was appointed Bishop of Cloyne in south Ireland, a position that he retained for most of the remainder of his life. Berkeley’s fame grew with his many publications, one of the most unusual of which was a work called Siris (1744), which details the medical benefits of tar-water, which he learned from Native Americans years earlier. He died of a stroke at age 67.


Idealism: No Material Objects

The heart of Berkeley’s philosophy is his theory of idealism: material things do not exist, and all reality exists as perceptions within the minds of spirits. The term “idealism” comes from the word “idea” insofar as the only things that exist are ideas in one’s mind. In that sense, a term like “idea-ism” might have better conveyed its meaning. A good way of understanding Berkeley’s position is to see it as taking Descartes’ evil genius hypothesis seriously. Consider again what Descartes suggested. For all I know, there is no material world whatsoever, and all of my experiences are hallucinations that are imposed into my mind by an evil genius. It might appear that I have a body and am sitting on a chair, but it could be that there is no three-dimensional world at all, and an evil genius is just making those things appear in my mind, while my mind itself floats around without any body. Descartes, we noted, did not actually believe this hypothesis, but only proposed it as a strategy for arriving at certainty about the world around us. Berkeley, however, does take this scenario seriously, although he rejects that there is anything sinister or deceptive about it. This is simply the way that God constructed the world: it is a virtual reality that consists of God continually feeding our spirit-minds sensory information in a very consistent way.

             Key here for Berkeley is the regularity and consistency with which God feeds our minds sensory data. God stores all sensible perceptions in his mind – in something like a master database – and he feeds them to us at the appropriate time. Imagine that I perceive myself to be in a room conversing with five friends. For Berkeley, the reality is that I and five other spirit-minds are being consistently fed similar sense data by God. Drawing from his master database of perceptions, God feeds us all sense data of walls, tables and chairs within the room. I decide to speak to my friends and say “Did you hear the President’s speech list night?” Drawing again from his master database of perceptions, God then interjects sensory data into all of our minds that portray the image of my mouth moving with audible words coming out. One of my friends decides to respond and say “The President’s speech was an insult to the intelligence of everyone in this country!” Another friend decides to say “I disagree, and think the President properly addressed the concerns of the nation.” In each case, God reads the thoughts of my friends and interjects sensory data into all of our minds, thus portraying them speaking. When we’re done conversing, we decide to get up and leave the room. We might then ask what happens to the empty room since God is no longer feeding us sense perceptions of it. Does the room go out of existence? According to Berkeley, no it does not: God himself is still perceiving the sensory information about the room and it continues to exist in his mind. Indeed, God continually monitors his master database of perceptions, and thus keeps the perceptions active. Berkeley expresses this point with the idealist motto that to be is to be perceived. That is, external things exist only in our minds or in God’s mind.

             On face value, the idealist position of denying material objects seems ridiculous. The vast majority of us believe that we live in a world of material objects that includes physical things like rocks, houses, chairs, and our own bodies. Berkeley, though, takes the opposite view: it is belief in the existence of material objects that is ridiculous. He writes,


It is indeed an opinion strangely prevailing amongst men, that houses, mountains, rivers, and in a word all sensible objects, have an existence, natural or real, distinct from their being perceived by the understanding. But, with how great an assurance and acquiescence soever this principle may be entertained in the world, yet whoever shall find in his heart to call it in question may, if I mistake not, perceive it to involve a manifest contradiction. For, what are the fore-mentioned objects but the things we perceive by sense? and what do we perceive besides our own ideas or sensations? and is it not plainly repugnant that any one of these, or any combination of them, should exist unperceived? [Principles, 4]


His point is that when I perceive something like a table, I’m not really experiencing any physical thing, but instead I’m only receiving sensations. This sensory data is all that I really know, and it is a colossal fabrication to assume that some physical thing is the source of my perceptions of the table. Berkeley recognizes that there is indeed some external source of my perception of the table, but that source is God, not some mysterious physical stuff. So natural is this position, he argues, that it is backed by common sense:


I am content . . . to appeal to the common sense of the world for the truth of my notion. Ask the gardener why he thinks yonder cherry-tree exists in the garden, and he shall tell you, because he sees and feels it; in a word, because he perceives it by his senses. Ask him why he thinks an orange-tree not to be there, and he shall tell you, because he does not perceive it. What he perceives by sense, that he terms a real, being, and says it is or exists; but, that which is not perceivable, the same, he says, has no being. . . . The question between the materialists and me is not, whether things have a real existence out of the mind of this or that person, but whether they have an absolute existence, distinct from being perceived by God, and exterior to all minds. [Dialogues, 3]


Berkeley is classified as an “empiricist” philosopher along with Locke. How, though, can Berkeley be an empiricist if he doesn’t believe in material objects? The answer is that the central point of empiricism involves gaining knowledge through the senses, rather than through innate ideas. And Berkeley wholeheartedly believes that we do acquire all of our knowledge through sense perception. The only issue involves what the source is of those sense perceptions. Whereas Locke believed that material objects feed us sensory information, Berkeley believed that God performs that role, not material things.


Arguments against Material Objects

As always with philosophy, it’s one thing to simply propose a theory, but quite another to prove it. Berkeley rises to the occasion, though, offering an abundance of arguments for his position. We’ll look at the two most compelling of these. The first is his argument from primary and secondary qualities. According to Locke, the fundamental difference between the two types of qualities is whether they are spectator dependent. Primary ones, such as shape, motion and solidity, are part of the external things themselves and not spectator dependent, where as secondary ones such as colors, sounds and tastes are not part of external things and are spectator dependent. On Locke’s view, primary qualities involve the fundamental nature of external things: they are three-dimensional, have solidity, and move around in a three dimensional area. To believe in external material objects, then, requires a commitment to the reality of primary qualities that exist in things, independently of what a spectator might perceive. Berkeley denies that there are any primary qualities of objects in this sense, and he argues instead that all so-called primary qualities are just as spectator dependent as secondary ones. In other words, all qualities of objects are really secondary and thus spectator dependent. His main argument is here:


They who assert that figure, motion, and the rest of the primary or original qualities do exist without the mind in unthinking substances, do at the same time acknowledge that colors, sounds, heat cold, and suchlike secondary qualities, do not—which they tell us are sensations existing in the mind alone, that depend on and are occasioned by the different size, texture, and motion of the minute particles of matter. This they take for an undoubted truth, which they can demonstrate beyond all exception. Now, if it be certain that those original [primary] qualities are inseparably united with the other sensible [secondary] qualities, and not, even in thought, capable of being abstracted from them, it plainly follows that they exist only in the mind. But I desire any one to reflect and try whether he can, by any abstraction of thought, conceive the extension and motion of a body without all other sensible qualities. For my own part, I see evidently that it is not in my power to frame an idea of a body extended and moving, but I must withal give it some color or other sensible quality which is acknowledged to exist only in the mind. [Principles, 10]


His main point is that so-called primary qualities are nothing beyond the secondary qualities that we perceive in things. Visual perceptions of shape, for example, are just patches of color, which are secondary.

             To make his case, Berkeley examines several so-called primary qualities and explains with each one how it is spectator dependent. Take, for example, the quality of extension, that is, three-dimensional shape. Our conceptions of an object’s shape hinge directly on the perspective of the spectator. The leg of a bug, for example, appears exceedingly small to us; to the bug itself it would appear to be a medium sized thing, yet to an even tinier microscopic organism it would appear to be huge. The texture of an object similarly hinges on the perspective from which we examine it. From a distance bug’s leg might appear to be smooth; through a microscope it might appear to be quite coarse. The point is that everything that we know about shape depends upon where we stand in relation to the things that we are perceiving; thus, all notions of shape are spectator dependent. The so-called primary quality of motion is also relative to the perceiver. Imagine, for example, that a leaf is falling from a tree directly in front of a humming bird, a human, and a sloth. How would each of these creatures perceive the leaf’s motion? To the humming bird the leaf’s motion might appear to be so slow as to be almost frozen in time. To the human it would appear to be moving at a normal pace. To the sloth it might appear exceedingly rapid. According to Berkeley, speed and time are measured by the succession of ideas in our minds, which varies in different perceivers.

             Berkeley’s second argument against material objects is based on the principle of simplicity: there is no real need for the material objects, hence would be a useless creation. Everything we need to perceive sensible qualities is accounted for more efficiently through idealism: God directly feeds us sensory information without creating the material world as a useless middleman. He writes,


If therefore it were possible for bodies to exist without the mind, yet to hold they do so, must needs be a very precarious opinion; since it is to suppose, without any reason at all, that God has created innumerable beings that are entirely useless, and serve to no manner of purpose. [Principles, 19]


In theory, we might think that God could have created the material world as a middleman if he wanted to, sort of as an instrument to accomplish the task. But even that, according to Berkeley, is inconsistent with God’s nature. Instruments are used only when there is a need. A hammer is a useful instrument since I can’t effectively pound in a nail with my bare hands. My glasses are a useful instrument since I can’t see very well without them. However, God, who has infinite powers, has no needs and thus has no use of any instrument that might help him accomplish some task. Berkeley writes:


We indeed, who are beings of finite powers, are forced to make use of instruments. And the use of an instrument shows the agent to be limited by rules of another’s prescription, and that he cannot obtain his end but in such a way, and by such conditions. Whence it seems a clear consequence, that the supreme unlimited agent uses no tool or instrument at all. [Dialogues, 2]


Thus, God is perfectly capable of feeding us sensory information directly without the need for him to create the material world as a crutch.


God and evil

Reconciling God’s existence with the presence of evil in the world has been a central concern among philosophers since at least the time of Augustine. Why would an all good God permit the enormous amount of suffering that we see in the world around us? The problem is especially acute for Berkeley’s theory since God not only permits suffering, but he also seems to be the originator of suffering as he injects all external sensory information into our minds. Imagine again that I perceive myself to be in a room conversing with five friends about the President’s speech. All of my perceptions of the room itself are implanted directly into my mind by God; the dialogue that I’m having with my friends also depends upon God feeding each of us sensations of our voices and bodily images. Suppose that our political conversation becomes heated, a fight erupts and in a fit of anger my friend throws me out the window; my spine is broken and I’m paralyzed for life from my neck down. Let’s now see what God’s role was in this tragedy. First, he enabled the controversy by mediating the sensory information of the dialogue. When things became heated, he could have just cut off the flow of perceptions. Second, since, according to Berkeley’s theory, I have no physical body, God alone is the source of whatever physical pain I experience from my so-called “physical injury”. Third, God is directly responsible for whatever continued incapacity I have as a quadriplegic. God decides to shut off all perceptions I might have of bodily movement and sensation in my arms and legs, and I’m stuck with that for life. While I and my friends are certainly morally responsible for our respective roles, God is nevertheless an active participant and conspirator in how I am affected.

             Berkeley has two responses to this criticism. First, he argues that the problem with God and evil is no more severe with his idealist theory than it is for those who believe in the existence of matter. In both cases, God is actively involved in sustaining a world that includes immorality and suffering. If a material world does exist, then it would just be an instrument in God’s hands, and a person is just as morally responsible whether or not he used an instrument. He writes,


the imputation of guilt is the same, whether a person commits an action with or without an instrument. In case therefore you suppose God to act by the mediation of an instrument or occasion, called matter, you as truly make Him the author of sin as I, who think Him the immediate agent in all those operations vulgarly ascribed to Nature. [Dialogues, 3]


Technically, this response does not attempt to solve the problem of God and evil, but only maintains that there is no extra problem added to the situation by endorsing Berkeley’s idealism.

             Berkeley’s second response, though, does attempt to solve the problem in a more positive way. According to Berkeley, evil does not consist of outward actions, but inward attitudes:


I farther observe that sin or moral turpitude does not consist in the outward physical action or motion, but in the internal deviation of the will from the laws of reason and religion. This is plain, in that the killing an enemy in a battle, or putting a criminal legally to death, is not thought sinful; though the outward act be the very same with that in the case of murder. Since, therefore, sin does not consist in the physical action, the making God an immediate cause of all such actions is not making Him the Author of sin. [Dialogues, ibid]


Thus, when God feeds us sensory information that involves immorality or is painful, his motives are pure. It is as though he is performing the role of a messenger or delivery service; sometimes the information is good, sometimes not so good. But we shouldn’t blame the messenger when we don’t like what he delivers. Ultimately the fault rests with the person who initially sent the message, not delivered it. With the present example, the fault rests solely with me and my friends.




The last of the great British empiricists was David Hume (1711-1776), who pushed empiricism to its skeptical conclusions. Hume was born near Edinburgh, Scotland into a moderately wealthy family, but the bulk of the family fortune went to Hume’s older brother after their father died, thus forcing Hume to be frugal for some decades. Educated in law at his family’s direction, he quickly abandoned that career and devoted himself to the study of philosophy. In his teens wrestled with the question of God’s existence, balancing the arguments on both sides, and soon rejected the notion of an all powerful divine being. In his early twenties he wrote the manuscript of his most important work, A Treatise of Human Nature (1739-1740). To Hume’s disappointment, it received little attention, and the discussion that it did generate was highly critical. Blaming its failure on the work’s technical style, he rewrote and published portions of it in a more reader-friendly format. Hume hoped to work as a philosophy teacher at one of Edinburgh’s universities, but the skeptical and anti-religious nature of his writings poisoned his efforts, and instead he took on temporary jobs in government and as a librarian. With a steady flow of publications, branching out into history as well as philosophy, by his mid forties he became one of the most famous—and controversial—authors in Europe. His wealth grew with his fame. In spite of the skeptical tone of his writings, Hume was a cheerful person and enjoyed socializing with people at all levels of society. Though he never married, he was well received by “modest women” as he words it in his autobiography. One of his friends was the controversial French author Jean Jacque Rousseau, who took political refuge in Hume’s home for a short time. Rousseau had mental problems, though, and, turning on his generous host, he publicly accused Hume of trying to sabotage his reputation. The event turned into an international scandal, and the two never reconciled. Hume died at age 65 from a digestive disorder that lingered for a year and left him emaciated. On his deathbed, crowds of people gathered around his Edinburgh home, curious to know whether he would repent of his irreligion. He held firm in his disbelief, and, in fact, one of his final acts was to plan for the posthumous publication of his most anti-religious writing, which he felt was too controversial to appear in print while he was alive.


Origin of and Association of Ideas

In his own day, as now, Hume had a notorious reputation as a skeptical philosopher, and in many ways he carried on the skeptical tradition forged in ancient Greece. Much of Hume’s skepticism, though, results from pushing the empiricist agenda to its logical conclusion. There are two main building blocks upon which his empiricist philosophy is founded. The first of these concerns the origin of ideas. Thoughts and ideas flow through our minds endlessly – ideas of people, houses, music concerts, scientific discoveries, God, on and on. Where do they all come from? Hume’s answer is that all of our ideas come from two types of experiences, or impressions as he calls them: (1) outward impressions through our five senses and (2) inward impressions through reflection on our mental operations. For example, the idea I have of the color red ultimately came from some outward sensory experience that I had of the color red that was stored in my memory. The idea I have of fear similarly came from an inward feeling of fear that I experienced in the past. He writes,


though our thought seems to possess this unbounded liberty, we shall find, upon a nearer examination, that it is really confined within very narrow limits. . . . When we think of a golden mountain, we only join two consistent ideas, gold, and mountain, with which we were formerly acquainted. . . . In short, all the materials of thinking are derived either from our outward or inward sentiment: The mixture and composition of these belongs alone to the mind and will. Or, to express myself in philosophical language, all our ideas or more feeble perceptions are copies of our impressions or more lively ones. [Enquiry, 2]


Hume offers two proofs for his position that all ideas are copied from impressions. First, he says that if you take any idea you have and examine its components, you’ll find that it traces back to outward or inward one or more sensory experience or inward feeling. Hume gives as an example the idea we have of God as “an infinitely intelligent, wise, and good Being. This, he says, “arises from reflecting on the operations of our own mind” and enlarging our human qualities of goodness and wisdom without limit. Second, he says that, if you go your entire life without having a particular type of sensation, then you would lack the corresponding idea of that sensation. For example, “a blind man can form no notion of colors.”

             On face value, Hume’s view is innocent enough, and he seems to just be reiterating Locke’s position that experience is the source of all our mental contents. What Hume does with this, though, is quite radical insofar as he transforms it into a theory of meaning. For my ideas to have any meaning, they must be grounded in some impression that I’ve had. An idea is meaningless, then, if I cannot trace it back to any impression. He writes,


When we entertain, therefore, any suspicion that a philosophical term is employed without any meaning or idea (as is but too frequent), we need but enquire, from what impression is that supposed idea derived? And if it be impossible to assign any, this will serve to confirm our suspicion. By bringing ideas into so clear a light we may reasonably hope to remove all dispute, which may arise, concerning their nature and reality. [Ibid]


For example, if I have an idea of an all-powerful divine being, but I’ve never had any impression of something that is all powerful or divine, then my idea is without meaning. Whatever I idea I do have of God – regardless of whether God even exists – it must be grounded in impressions that I’ve had. It is this theory of meaning that leads Hume down the path of skepticism as he explores one philosophical theory after another. In fact, he believes that much of traditional philosophy and religion can be dismissed as meaningless since it fails this test.

             The second building block of Hume’s empiricism is his theory of the association of ideas. Suppose that I sit down on a couch and let my mind wander where it will. I think about the President, then Japan, then my car, then a telephone pole, then a railroad track, then an old apartment I lived in. It is tempting to think that I am conjuring up these ideas spontaneously without any organization behind them. Not so, Hume argues. Our flow of ideas is connected together by three principles of association. First is resemblance, where one thought leads to another because of resembling features that they have. For example, if I look at a photograph of a friend, I’ll start thinking about that friend. Second is contiguity, that is, one thing being in close proximity to another. For example, if someone says something about a store in a shopping mall, I might then think about the store located next to it. Third is cause and effect. For example, if I look at a scar on my arm, I immediately start thinking about the accident I had that caused me to get the scar. These three principles alone, according to Hume, are responsible for all mental association that our minds make in the normal flow of ideas. With the above example, my thought about the President leads me to think about Japan since he recently visited there (contiguity); Japan is where my car was built (causality); my car is parked next to a telephone pole (contiguity); the telephone pole is covered with the same kind of black tar that’s on railroad ties (resemblance); my old apartment was along side a railroad track (contiguity). Hume says that “The more instances we examine, and the more care we employ, the more assurance shall we acquire, that the enumeration, which we form from the whole, is complete and entire” (Enquiry, 3).


Personal Identity and Causality

Hume’s skepticism emerges quite clearly with his treatment of two philosophical notions, namely personal identity and causality. In both of these cases his skeptical conclusions arise from applying the theory of meaning described above. If the traditional ideas of causality and personal identity are to be meaningful, then we must be able to trace those ideas back to some impression. In each case, though, there are problems locating an impression that is suitable for forming these ideas.

             Let’s start with the idea of personal identity. The traditional notion of personal identity held by Descartes and other philosophers is that it is a single, unified substance that continues through time. On this view, I am a single conscious entity, and, even though my specific thoughts change, my identity remains intact throughout time, and perhaps even into the afterlife. The critical question for Hume, then, is “what impression is the basis of this traditional idea of personal identity?” His skeptical answer is that we have no actual experience—or internal impression—of a unified, continuous self; thus the traditional notion of personal identity is meaningless. If I introspectively examine the actual experience I have of my identity, I’ll discover that it consists only of various perceptions that come and go, such as feelings of heat or cold. He writes,


For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe any thing but the perception. . . . The mind is a kind of theatre, where several perceptions successively make their appearance; pass, repass, glide away, and mingle in an infinite variety of postures and situations. There is properly no simplicity in it at one time, nor identity in different. . . . [Treatise, 1.4.6]


Thus, the inward impression that I have of my identity is that of an ever-shifting bundle of perceptions, and this is the impression that must form the basis of my true notion of personal identity.

             Hume analyzes the traditional notion of causality in the same way, first attempting to discover some impression that forms the idea, then abandoning the traditional notion when the appropriate impression can’t be found. Let’s begin with a simple example of a cause-effect connection, which Hume himself uses: billiard ball A strikes billiard ball B and causes it to move. The traditional notion of causality is that there is an external power or force that causes ball A to strike and move ball B, independently of what you or I might perceive when we watch the balls move. Think of it like an invisible explosion that occurs when A strikes B and forces it to move. That is, there is an objective necessary connection between the cause and effect. Applying Hume’s theory of meaning, for this idea of necessary connection to be meaningful, we need to discover the impression which forms the basis of it.

             One possibility is that we perceive an outward impression through our five senses that forms the idea of an objective necessary connection. But do we? Suppose that when ball A struck ball B, it produced a flash of light and a loud boom, and, in fact, that every causal connection we saw was similarly accompanied by a light flash and a boom. If that was the case, then, yes, we would have a very strong outward impression that would give us the idea of an objective necessary connection. But that’s not what happens. When A strikes and moves B, all that appears to our eyes is the motion of two balls, and that’s it. He writes,


When we look about us towards external objects, and consider the operation of causes, we are never able, in a single instance, to discover any power or necessary connection; any quality, which binds the effect to the cause, and renders the one an infallible consequence of the other. We only find, that the one does actually, in fact, follow the other. The impulse of one billiard- ball is attended with motion in the second. This is the whole that appears to the outward senses.  [Enquiry, 7]


He next considers whether there is any inward impression that forms the idea of necessary connection. Locke had suggested one possibility: we experience a feeling of causal power when we willfully move parts of our bodies, such as when I raise my arm. Here we have a causal sequence where the cause is my mental decision and the effect is the raising of my arm. Since the causal sequence is taking place within my own mind, I am thus capable of directly experiencing a feeling of causal power or necessary connection when I willfully raise my arm. But Hume rejects this as well, since we don’t have a clear experience of how or where such willful bodily motion takes place. Indeed, I do mentally experience my willful decision (the cause) and I do see and feel my arm move (the effect), but I don’t experience anything that links them. I don’t feel a special electrical shock or anything unique to the necessary connection by itself.

             In the absence of an appropriate outward or inward impression, we must then reject the traditional notion of necessary connection as an objective force or invisible explosion. He suggests an alternative, though. There is a more moderate notion of necessary connection that comes from an inward feeling of expectation that occurs when we repeatedly see A followed by B. Consider again the example of billiard balls: it is only after repeatedly seeing ball A move B that our minds feel a transition from the cause to the effect. He writes,


The first time a man saw the communication of motion by impulse, as by the shock of two billiard balls, he could not pronounce that the one event was connected: But only that it was conjoined with the other. After he has observed several instances of this nature, he then pronounces them to be connected. What alteration has happened to give rise to this new idea of connection? Nothing but that he now feels these events to be connected in his imagination, and can readily foretell the existence of one from the appearance of the other. [Ibid]


In the end, Hume does not completely reject the idea of necessary connection and causality. But he does reject the traditional idea of it being something like a primary quality within objects themselves. Instead, he suggests that necessary connection is like a secondary quality that we spectators impose onto A-B sequences when we repeatedly see A and B conjoined. It’s just a habit of our minds, not a reality in the objects themselves.


Belief in Miracles

One of Hume’s lifelong goals was to help rid the world of religious superstition and fanaticism, and nowhere is this better seen than with his attack on the belief in miracles. To properly understand exactly what Hume is criticizing, three things need to be clarified. First, Hume as in mind a very precise notion of the term “miracle”, which is that it is a violation of a law of nature. It is not simply an unusual event that occurs at just the right moment, such as if I’m saved from drowning by grabbing onto a vine that just happens to be hanging from a tree within my reach. Rather, it must break some law of nature, such as if my arm gets chopped off and a new one instantly appears. Second, Hume focuses specifically on reports of miracles—stories about miracles that we hear about from other people or read about in books such as the Bible. He does not consider miracles that we might directly witness ourselves. Third, Hume focuses on whether it is reasonable for us to believe reports of miracles, not whether the miraculous event actually took place. It is impossible for us to go back in time and prove with absolute certainty whether any reported miracle was genuine. The best we can do is consider whether the evidence in support of a miracle report is compelling enough for us to believe the report. Hume’s precise position, then, is that it is never reasonable to believe reports of violations of laws of nature.

             Hume offers a series of arguments against belief in miracles, but his main one is this: it is never reasonable to believe in reports of miracles since those reports will always be outweighed by stronger evidence for consistent laws of nature. Suppose, for example, that the Mayor and all the city officials say that they witnessed a genuine miracle. As they report, a car rammed into city hall, causing the wall to collapse, but seconds later all the smashed pieces of the wall floated into the air, and reassembled themselves just as they were before. Should we believe their report?

             According to Hume, our first step is to weigh the evidence for and against this miracle, sort of like we were placing the evidence in the pans of a balance scale. On the one side, the evidence that we have in favor of the miracle is the credibility of the witnesses. They are reporting what they’ve seen with their eyes, and we know from past experience that they are people of their word. On the other side, the evidence against the miracle consists of the accumulated experience that we have in favor of uniform laws of nature. The natural world behaves in an orderly way based to natural laws. We count on this every moment of the day as when, for example, I open a door and expect it to swing on a hinge, rather than do something like transform into a bird and fly away. According to Hume, the evidence that we have in favor of consistent laws of nature is overwhelming, and will always outweigh even the best evidence in favor of a reported miraculous violation of a law of nature. He writes,


A miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined. . . . There must, therefore, be a uniform experience against every miraculous event, otherwise the event would not merit that appellation [i.e., that title]. And as a uniform experience amounts to a proof, there is here a direct and full proof from the nature of the fact against the existence of any miracle. . . . [Enquiry, 10]


For Hume, since miracles are defined as violations of laws of nature, any alleged miracle report is instantly outweighed by overwhelming evidence that we have of consistent laws of nature. The wise thing to do, Hume says, is to proportion our belief to the evidence. With the above City Hall example, we should thus disbelieve the report that the wall miraculously reassembled itself since the evidence is overwhelmingly in favor of consistent laws of nature.

             In addition to this main argument against belief in miracles, Hume offers four additional criticisms. First, he says, the witnesses who report miracles typically lack credibility. Sometimes they lack sufficient education and good sense, which makes them gullible. Other times they are consciously deceptive. Even in the above example of the City Hall miracle, our first reaction would be to suspect that the Mayor and the city officials concocted the story to hide something politically sensitive. Second, Hume argues that human beings are predisposed to enjoy hearing sensational stories, and this creates an instant audience for accounts of miraculous events. In recent times, we see this in the success of tabloid publications such as the National Enquirer that specialize in stories about alien abductions, monsters such as Bigfoot, and every possible type of miracle. This vulnerability within human nature itself casts doubt on the truth of such sensational claims. Third, Hume states that reports of miracles typically come from pre-scientific and primitive countries whose cultures are obsessed with the supernatural. The most ordinary natural events are ascribed to supernatural causes, and reliance on omens and oracles is the norm. The very location of such miracle reports counts against their credibility. Fourth, Hume argues that reports of miracles support rival religious systems, and thus nullify each other. There are reports of miracles within virtually every religious tradition around the world. Christian miracles support the Christian plan of salvation. Muslim miracles support the Muslim plan of salvation, and so on. The problem is that these religions are rivals to each other and typically discredit the others’ legitimacy. Taken as a whole, then, rival miracle reports are mutually undermining.

             Hume recognizes that the Christian religious tradition not only contains reports of miracles, but is in fact founded on miraculous circumstances in the lives of the Biblical characters. Nevertheless, Hume argues, the reasonable thing to do even here is to disbelieve these reports. In fact, belief in such miracle stories is so irrational that it would take an act of God to make an otherwise reasonable person suspend “all the principles of his understanding” and make him believe a miracle story that “is most contrary to custom and experience” (ibid).


Morality: Reason vs. Sentiment

Throughout the history of philosophy, the traditional conception of morality was that it consists of objective universal truths that can be discovered through human reason. Plato’s view of the forms is the clearest example of this. For Plato, moral standards such as justice and goodness exist independently of human society in the higher spirit-realm of the forms. And, for Plato, it takes a mental act of reason to grasp moral truths, in much the way it takes an act of reason to grasp mathematical truths which also reside in the realm of the forms. This is largely the view of morality that moral philosophers in Hume’s day held: we discover objective universal moral principles through reason. Hume rejects this view: morality is not grounded in an objective feature of the external world, but rather on internal mental feelings of pleasure and pain.

             Hume’s main argument for his position is that, as hard as we may try, we can never discover any special fact about an action that makes it either moral or immoral – either within the physical act itself or in any alleged higher realm of moral truths. All that we will find is a feeling of pleasure or pain in reaction to the action. He writes,


Take any action allowed to be vicious; willful murder, for instance. Examine it in all lights, and see if you can find that matter of fact, or real existence, which you call vice. In whichever way you take it, you find only certain passions, motives, volitions, and thoughts. There is no other matter of fact in the case. The vice entirely escapes you, as long as you consider the object. You never can find it, till you turn your reflection into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action. Here is a matter of fact; but it is the object of feeling, not of reason. It lies in yourself, not in the object. So that when you pronounce any action or character to be vicious, you mean nothing, but that from the constitution of your nature you have a feeling or sentiment of blame from the contemplation of it. [Treatise, 3.1.1]


Thus, morality does not involve making a rational judgment about some objective moral facts. Instead, moral assessments are just emotional reactions. If I see someone robbing a bank and determine that action to be morally wrong, I am not making a rational judgment about some objective moral truth or fact; rather, I am experiencing a feeling of emotional pain, and that feeling constitutes my negative assessment of the robber.  Using the terminology of primary and secondary qualities, Hume’s point is that morality is not a primary quality that’s part of external things, but is instead like a secondary quality that spectators impose onto actions. He writes, “Vice and virtue, therefore, may be compared to sounds, colors, heat, and cold, which, according to modern philosophy, are not [primary] qualities in objects, but perceptions in the mind” (ibid).

             As obvious as this all seems to Hume, he notes that most moral theories insist on linking moral assessments with some factual judgment of reason. They begin by listing some kind of fact, such as a fact about moral Forms, moral truths, divine commands; from these facts, then, they immediately jump to some moral statement, such as “Stealing is wrong”. He makes this point here:


In every system of morality which I have hitherto met with, I have always remarked, that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when of a sudden I am surprised to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not.


The problem, for Hume, is that you just can’t rationally deduce a statement of moral obligation from a statement of fact—stated more succinctly, you cannot derive ought from is. Rather, the obligation comes from feeling, not from deduction of facts. When I see a bank robber and state that “The robber’s act of stealing is wrong”, I am expressing the painful feelings that I am experiencing. Thus, statements of moral obligation are introduced through an emotional reaction, not through a rational deduction.


Radical Skepticism and Natural Belief

Hume was a chronically skeptical philosopher, and we’ve already seen several expressions of this. He began with a theory of meaning that ruthlessly dismembers any concept that is not grounded in an outward or inward impression, and the first victims were traditional notions of personal identity and causality. He questioned the legitimacy of belief in miracles and, in essence, called into doubt anything supernatural. Finally, he attacked the traditional notion of rationally perceived moral truths, and reduced moral assessments to emotional reactions. But there is an even more radical skepticism within Hume’s philosophy that goes beyond these particular issues. According to Hume, the underlying structure of human reason itself is inherently flawed, and thus completely untrustworthy. Specifically, the human reasoning process, even at its very best, is on a collision course with itself and regularly contradicts itself. If we follow one rational train of thought we reach conclusion A; if we follow a different rational train of thought we reach a conflicting conclusion “not A”. It’s like a computer that is running two incompatible programs that eventually cause the computer to crash. Hume describes this collision course here:


The intense view of these manifold contradictions and imperfections in human reason has so wrought upon me, and heated my brain, that I am ready to reject all belief and reasoning, and can look upon no opinion even as more probable or likely than another. Where am I, or what? From what causes do I derive my existence, and to what condition shall I return? Whose favor shall I court, and whose anger must I dread? What beings surround me? and on whom have I any influence, or who have any influence on me? I am confounded with all these questions, and begin to fancy myself in the most deplorable condition imaginable, environed with the deepest darkness, and utterly deprived of the use of every member and faculty. [Treatise, 1.4.7]


For Hume, then, the most central questions about human existence are incapable of being adequately answered because of the inherent flaws in the human reasoning process. Whatever reason tells us about these matters can never be fully trusted, and thus we slide down the slope of philosophical despair.

             Amidst all this skepticism and despair, though, Hume has a strangely optimistic solution. Human nature has embedded within us some very concrete natural beliefs which enable us to get through the day. Nature forces us to believe in external objects, causal relationships, personal identity, moral responsibility and a host of other notions that are crucial for our normal routines. These are not innate ideas per se, but are normal beliefs about the world that emerge through natural inclinations. For example, when I look at a chair and I’m naturally inclined to think that it exists in the external world exactly as I perceive it. The fact that we have these natural beliefs doesn’t mean that they are entirely true, and Hume warns that many are not. However, they are functionally important for our lives. Also, they serve as a natural antidote to philosophical despair. When radical skepticism causes us to mentally crash, all that we need to do is back off from our philosophical inquiries and let our natural beliefs take over: “Nature herself suffices to that purpose, and cures me of this philosophical melancholy and delirium” (ibid). Hume warns that natural beliefs are no replacement for philosophical inquiry, which, even with all its skepticism, is still important to keep us from giving in to gullibility and superstition. As flawed as human reason is, it is still preferable to “superstition of every kind or denomination” (ibid).




Introduction: John Locke argued that our minds are from birth a blank slate and all of the conceptions we have originate from experience. His first step in establishing this is to attack the view that there are foundational innate ideas that we are born with. In the following he presents this attack, and specifically targets the common philosophical view that there are two laws of thought that are innate: “Whatsoever is, is,” and “It is impossible for the same thing to be and not to be”. According to Locke, these notions are not innate, but arrived at through experience.


Innate Ideas Debunked by Showing how we Actually get our Ideas

1. It is an established opinion among some people that there are in the understanding certain innate principles (some primary notions, common notions, characters) as it were stamped upon the mind of man, which the soul receives in its very first being and brings into the world with it. It would be sufficient to convince unprejudiced readers of the falseness of this supposition, if I should only show (as I hope I shall in the following parts of this Discourse) how people, barely by the use of their natural faculties, may attain to all the knowledge they have, without the help of any innate impressions, and may arrive at certainty without any such original notions or principles. . . .


Universal Assent the Main Argument for Innate Ideas

2. There is nothing more commonly taken for granted than that there are certain principles, both speculative and practical, (for they speak of both), universally agreed upon by all men: which therefore, they argue, must needs be the constant impressions which the souls of people receive in their first beings, and which they bring into the world with them, as necessarily and really as they do any of their inherent faculties.


Universal Consent Proves Nothing Innate

3. This argument, drawn from universal consent, has this misfortune in it, that if it were true in matter of fact, that there were certain truths wherein all men agreed, it would not prove them innate, if there can be any other way shown how people may come to that universal agreement, in the things they do consent in, which I presume may be done.


Two Laws of Thought Not Universally Assented To

4. But, which is worse, this argument of universal consent (which is made use of to prove innate principles) seems to me a demonstration that there are none such. [This is] because there are none to which all men give a universal assent. I shall begin with the speculative, and instance in those magnified principles of demonstration, “Whatsoever is, is,” and “It is impossible for the same thing to be and not to be”; which, of all others, I think have the most allowed title to innate. These [so-called “Laws of Thought”] have so settled a reputation of maxims universally received, that it will no doubt be thought strange if anyone should seem to question it. But yet I take liberty to say, that these propositions are so far from having an universal assent, that there are a great part of men to whom they are not so much as known.


Not on the Mind Naturally Imprinted, Because Not Known to Children, Idiots, etc.

5. For, first, it is evident, that all children and idiots have not the least apprehension or thought of them. And the want of that is enough to destroy that universal assent which must needs be the necessary concomitant of all innate truths: it seeming to me near a contradiction to say, that there are truths imprinted on the soul, which it perceives or understands not: imprinting, if it signify anything, being nothing else but the making certain truths to be perceived. For to imprint anything on the mind without the mind’s perceiving it, seems to me hardly intelligible. If therefore children and idiots have souls, have minds, with those impressions upon them, they must unavoidably perceive them, and necessarily know and assent to these truths. . . .


That People Know Them when they Come to the Use of Reason, Answered

6. To avoid this, it is usually answered, that all people know and assent to them, when they come to the use of reason; and this is enough to prove them innate. I answer:


7. Doubtful expressions, that have scarce any signification, go for clear reasons to those who, being prepossessed, take not the pains to examine even what they themselves say. For, to apply this answer with any tolerable sense to our present purpose, it must signify one of these two things: either that as soon as people come to the use of reason these supposed native inscriptions come to be known and observed by them; or else, that the use and exercise of people’s reason assists them in the discovery of these principles, and certainly makes them known to them.


If Reason Discovered them, that would not Prove Them Innate

8. If they mean that by the use of reason people may discover these principles (and that this is sufficient to prove them innate) their way of arguing will stand thus, viz. that whatever truths reason can certainly discover to us, and make us firmly assent to, those are all naturally imprinted on the mind. . . .


Reason does not Discover Them: Reason deduces Truths, but Deduced Ideas are not Innate]

9. But how can these people think [that] the use of reason [is] necessary to discover principles that are supposed innate, when reason (if we may believe them) is nothing else but the faculty of deducing unknown truths from principles or propositions that are already known? That certainly can never be thought innate which we have need of reason to discover. . . .


The Coming to the Use of Reason Not the Time we Come to Know These Maxims

12.  If by knowing and assenting to them “when we come to the use of reason,” be meant that this is the time when they come to be taken notice of by the mind; and that as soon as children come to the use of reason, they come also to know and assent to these maxims, this also is false and frivolous. First, it is false because it is evident [that] these maxims are not in the mind so early as the use of reason. And therefore the coming to the use of reason is falsely assigned as the time of their discovery. How many instances of the use of reason may we observe in children, a long time before they have any knowledge of this maxim, “That it is impossible for the same thing to be and not to be?” And a great part of illiterate people and savages pass many years, even of their rational age, without ever thinking on this and the like general propositions. . . .


Not Innate, because not Universally Assented To

24. To conclude this argument of universal consent, I agree with these defenders of innate principles, that if they are innate, they must needs have universal assent. For that a truth should be innate, and yet not assented to, is to me as unintelligible, as for a man to know a truth, and be ignorant of it, at the same time. But then, by these men’s own confession, they cannot be innate; since they are not assented to by those who understand not the terms, nor by a great part of those who do understand them, but have yet never heard nor thought of those propositions; which, I think, is at least one half of mankind. But were the number far less, it would be enough to destroy universal assent, and thereby show these propositions not to be innate, if children alone were ignorant of them.




Introduction: In the following dialogue by George Berkeley, the character of Philonous represents Berkeley’s idealist position that material objects do not exit, and the things that we perceive exist only our minds or God’s mind. Hylas represents the ordinary person like you and I who believe that material objects exist. Berkeley presents two arguments against the existence of material objects below. The first is an attack on primary qualities, that is, qualities like three- dimensionality that are believed to be features of the external material world. He argues here that primary qualities are spectator dependent just as secondary qualities are. Second, he attacks the view that somehow God created material objects as an instrument for us to perceive things.


Against Primary Qualities of Three-Dimensional Extension in Material Objects

             Philonous: But what if the same arguments which are brought against Secondary Qualities will hold good against these also?

             Hylas: Why then I shall be obliged to think, they too exist only in the mind.

             Philonous: Is it your opinion the very [three-dimensional] figure and extension which you perceive by sense exist in the outward object or material substance?

             Hylas: It is.

             Philonous: Have all other animals as good grounds to think the same of the [three-dimensional] figure and extension which they see and feel?

             Hylas: Without doubt, if they have any thought at all.

             Philonous: Answer me, Hylas: Think you the senses were bestowed upon all animals for their preservation and well-being in life? or were they given to men alone for this end?

             Hylas: I make no question but they have the same use in all other animals.

             Philonous: If so, is it not necessary they should be enabled by them to perceive their own limbs, and those bodies which are capable of harming them?

             Hylas: Certainly.

             Philonous: A mite therefore must be supposed to see his own foot, and things equal or even less than it, as bodies of some considerable dimension; though at the same time they appear to you scarce discernible, or at best as so many visible points?

             Hylas: I cannot deny it.

             Philonous: And to creatures less than the mite they will seem yet larger?

             Hylas: They will.

             Philonous: Insomuch that what you can hardly discern will to another extremely minute animal appear as some huge mountain?

             Hylas: All this I grant.

             Philonous: Can one and the same thing be at the same time in itself of different dimensions?

             Hylas: That were absurd to imagine.

             Philonous: But, from what you have laid down it follows that both the [three-dimensional] extension by you perceived, and that perceived by the mite itself, as likewise all those perceived by lesser animals, are each of them the true extension of the mite’s foot; that is to say, by your own principles you are led into an absurdity.

             Hylas: There seems to be some difficulty in the point.

             Philonous: Again, have you not acknowledged that no real inherent property of any object can be changed without some change in the thing itself?

             Hylas: I have.

             Philonous: But, as we approach to or recede from an object, the visible [three-dimensional] extension varies, being at one distance ten or a hundred times greater than another. Does it not therefore follow from hence likewise that it is not really inherent in the object?

             Hylas: I own I am at a loss what to think.

             Philonous: Your judgment will soon be determined, if you will venture to think as freely concerning this quality as you have done concerning the rest. Was it not admitted as a good argument, that neither heat nor cold was in the water, because it seemed warm to one hand and cold to the other?

             Hylas: It was.

             Philonous: Is it not the very same reasoning to conclude, there is no [three-dimensional] extension or figure in an object, because to one eye it shall seem little, smooth, and round, when at the same time it appears to the other, great, uneven, and regular?

             Hylas: The very same. But does this latter fact ever happen?

             Philonous: You may at any time make the experiment, by looking with one eye bare, and with the other through a microscope.


Matter not an Instrument since God needs no Instrument to Cause Perception

             Hylas: I give up the point entirely. But, though Matter may not be a cause, yet what hinders its being an instrument, subservient to the supreme Agent in the production of our ideas?

             Philonous: An instrument say you; pray what may be the figure, springs, wheels, and motions, of that instrument?

             Hylas: Those I pretend to determine nothing of, both the substance and its qualities being entirely unknown to me.

             Philonous: What? You are then of opinion it is made up of unknown parts, that it has unknown motions, and an unknown shape?

             Hylas: I do not believe that it has any figure or motion at all, being already convinced, that no sensible qualities can exist in an unperceiving substance. . . .

             Philonous: What mean you by the general nature or notion of instrument?

             Hylas: That which is common to all particular instruments composes the general notion.

             Philonous: Is it not common to all instruments, that they are applied to the doing those things only which cannot be performed by the mere act of our wills? Thus, for instance, I never use an instrument to move my finger, because it is done by a volition. But I should use one if I were to remove part of a rock, or tear up a tree by the roots. Are you of the same mind? Or, can you show any example where an instrument is made use of in producing an effect immediately depending on the will of the agent?

             Hylas: I own I cannot.

             Philonous: How therefore can you suppose that an all-perfect spirit, on whose will all things have an absolute and immediate dependence, should need an instrument in his operations, or, not needing it, make use of it? Thus it seems to me that you are obliged to own the use of a lifeless inactive instrument to be incompatible with the infinite perfection of God; that is, by your own confession, to give up the point. . . .


Unperceived things do not Disappear since God Sustains Ideas of all Things

             Hylas: Supposing you were annihilated, cannot you conceive it possible that things perceivable by sense may still exist?

             Philonous: I can; but then it must be in another mind. When I deny sensible things an existence out of the mind, I do not mean my mind in particular, but all minds. Now, it is plain they have an existence exterior to my mind; since I find them by experience to be independent of it. There is therefore some other mind wherein they exist, during the intervals between the times of my perceiving them: as likewise they did before my birth, and would do after my supposed annihilation. And, as the same is true with regard to all other finite created spirits, it necessarily follows there is an omnipresent eternal mind, which knows and comprehends all things, and exhibits them to our view in such a manner, and according to such rules, as he himself has ordained, and are by us termed the laws of nature.




Introduction: David Hume was skeptical about many concepts that people ordinarily take for granted, such as the existence of external causal power, miracles, God. One of his usual skeptical techniques is to argue that if we do not have any experience to support a particular concept, such as “external causal power” then that concept is just a meaningless set of words. He uses this skeptical technique in the following where he questions the idea that we have a self or personal identity that is unified and continues over time. According to Hume, we have no experience of a unified and continuous self, and, instead, all that we experience about ourselves is a fleeting bundle of mental perceptions.


No Direct Experience of a Continuous Self

There are some philosophers who imagine we are every moment intimately conscious of what we call our self; that we feel its existence and its continuance in existence; and are certain, beyond the evidence of a demonstration, both of its perfect identity and simplicity. The strongest sensation, the most violent passion, say they, instead of distracting us from this view, only fix it the more intensely, and make us consider their influence on self either by their pain or pleasure. To attempt a further proof of this were to weaken its evidence; since no proof can be derived from any fact of which we are so intimately conscious; nor is there anything of which we can be certain if we doubt of this.

             Unluckily all these positive assertions are contrary to that very experience which is pleaded for them; nor have we any idea of self, after the manner it is here explained. For, from what impression could this idea be derived? This question it is impossible to answer without a manifest contradiction and absurdity; and yet it is a question which must necessarily be answered, if we would have the idea of self pass for clear and intelligible. It must be someone impression that gives rise to every real idea. But self or person is not any one impression, but that to which our several impressions and ideas are supposed to have a reference. If any impression gives rise to the idea of self, that impression must continue invariably the same, through the whole course of our lives; since self is supposed to exist after that manner. But there is no impression constant and invariable. Pain and pleasure, grief and joy, passions and sensations succeed each other, and never all exist at the same time. It cannot therefore be from any of these impressions, or from any other, that the idea of self is derived; and consequently there is no such idea.


Personal Identity Only a Bundle of Fleeting Perceptions

But further, what must become of all our particular perceptions upon this hypothesis? All these are different, and distinguishable, and separable from each other, and may be separately considered, and may exist separately, and have no need of anything to support their existence. After what manner therefore do they belong to self, and how are they connected with it? For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe anything but the perception. When my perceptions are removed for any time, as by sound sleep, so long am I insensible of myself, and may truly be said not to exist. And were all my perceptions removed by death, and could I neither think, nor feel, nor see, nor love, nor hate, after the dissolution of my body, I should be entirely annihilated, nor do I conceive what is further requisite to make me a perfect nonentity. If anyone, upon serious and unprejudiced reflection, thinks he has a different notion of himself, I must confess I can reason no longer with him. All I can allow him is, that he may be in the right as well as I, and that we are essentially different in this particular. He may, perhaps, perceive something simple and continued, which he calls himself; though I am certain there is no such principle in me.

             But setting aside some metaphysicians of this kind, I may venture to affirm of the rest of mankind, that they are nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement. Our eyes cannot turn in their sockets without varying our perceptions. Our thought is still more variable than our sight; and all our other senses and faculties contribute to this change: nor is there any single power of the soul, which remains unalterably the same, perhaps for one moment. The mind is a kind of theatre, where several perceptions successively make their appearance; pass, repass, glide away, and mingle in an infinite variety of postures and situations. There is properly no simplicity in it at one time, nor identity in different, whatever natural propension we may have to imagine that simplicity and identity. The comparison of the theatre must not mislead us. They are the successive perceptions only, that constitute the mind; nor have we the most distant notion of the place where these scenes are represented, or of the materials of which it is composed.




Please answer all of the following questions.


1. What are the so-called speculative and practical innate ideas, and what is Locke’s main argument against them?

2. Explain Locke’s distinction between ideas of sensation and ideas of reflection.

3. Explain Locke’s view of simple ideas, complex ideas, and the three mental processes involved in forming complex ideas.

4. Explain Locke’s distinction between primary, secondary and tertiary qualities.

5. Explain Locke’s view of the state of nature, the fundamental law of nature, and the justification of revolution.

6. Explain Berkeley’s idealism and God’s role as the source of perceptions.

7. Explain Berkeley’s arguments for idealism from primary/secondary qualities and simplicity.

8. Explain Berkeley’s two solutions to the problem of God and evil.

9. Explain Hume’s view of the origin of ideas and the test for meaning.

10. Explain Hume’s three principles of the association of ideas.

11. What is the traditional notion of the self, and what is Hume’s criticism of it?

12. What is the traditional notion of necessary connection, and what is Hume’s alternative explanation?

13. What is Hume’s main argument against miracles and his four additional arguments against miracles.

14. Explain Hume’s view about emotion and moral judgment, and his view that “ought cannot be derived from is”.

15. Explain Hume’s view of radical skepticism and natural belief.

[Reading 1: Locke against Innate Ideas]

16. What is Locke’s criticism of the argument for innate ideas from universal consent?

17. What is Locke’s criticism of the view that reason discovers innate ideas?

[Reading 2: Berkeley against Material Objects]

18. Explain Berkeley’s criticism of primary qualities of three-dimensional extension in material objects.

19. Explain Berkeley’s criticism of the view that God created matter as an instrument to cause perception of external objects within humans.

[Reading 3: Hume against a Continuous Self]

20. Explain Hume’s reasoning for his view that personal identity is only a bundle of fleeting perceptions.

[Short Essay]

21. Short essay: pick any one of the following views in this chapter and criticize it in a minimum of 150 words. Locke: critique of innate ideas; ideas of sensation and reflection; simple and complex ideas; primary and secondary qualities; natural rights. Berkeley: argument against primary qualities; simplicity argument for idealism; response to the problem of evil. Hume: all ideas copied from impressions; test for meaning; association of ideas; personal identity; causality; miracles; morality; radical skepticism.