The Rationalist, Rene Descartes

Cartesian Dualism

Any philosophical position that divides existence into two completely distinct, independent, unique substances or kinds of things is a form of dualism. The distinction can be between mind and body, natural and supernatural, spirit and matter, soul and body, good and evil, and so on. (Monism is the general name for the belief that everything consists of only one, ultimate, unique substance, such as matter; pluralism is the name for the belief in more than one substance.) Cartesian dualism refers to Descartes's conviction that human beings are a mysterious union of mind (soul) and body, of incorporeal substance and corporeal substance, with each realm operating according to separate sets of laws. The mind follows the laws of reason but otherwise is free. The body is governed by the laws of physics and falls under the rule of cause and effect: The human body is no freer than any other material thing. The soul is somehow dispersed to all parts of the body, but thinking enters the brain through the pineal gland: And as a clock composed of wheels and counter-weights no less exactly observes the laws of nature . . . if I consider the body of a man as being a sort of machine so built up and composed of nerves, muscles, veins, blood, and skin, that though there were no mind in it at all, it would not cease to have made the same motions as at present, exception being made of those movements which are due to the direction of the will, and in consequence depend upon the mind. If we can understand thinking without ever referring to the body, and if we can understand the body without ever referring to the mind/soul, then minds and bodies are essentially independent of each other. Science can study bodies and the natural world without ever treading in theology. Initially, this rationale seems satisfactory. Indeed, it fits the commonsense view of Christian theology and ordinary experience. Thus, Cartesian dualism allows for the doctrine of the soul's continued existence after the body's death. Further, by defining himself as thinking substance rather than corporeal, Descartes reaffirms the primacy of the soul over the body. Human beings are essentially spiritual beings who happen to inhabit bodies. As a devout believer, Descartes appears to have found a way to salvage his faith from the threats of purely materialistic science. As a scientist, he has freed science to progress without church interference, since scientific discoveries are about the body and have no real bearing on the nature of the soul.

The Perfect Idea of Perfection

As a rationalist, Descartes cannot appeal to Aquinas's arguments for the existence of God (Chapter 8) because they are based on claims about the external world, the existence of which Descartes has yet to establish. Indeed, Descartes needs to establish the existence of God in order to establish the existence of the external world. Descartes can—at this point—only examine the nature and quality of his own ideas: I shall now close my eyes, I shall stop my ears, I shall call away all my senses, I shall efface even from my thoughts all the images of corporeal things, or at least (for that is hardly possible) I shall esteem them as vain and false; and thus holding converse only with myself and considering my own nature, I shall try little by little to reach a better knowledge of and a more familiar acquaintanceship with myself. Clearly, Descartes says, the idea of God exists. He notes the obvious: Such an idea does exist—he has it. But does it follow that an object corresponding to this idea exists? Hence there remains only the idea of God, concerning which we must consider whether it is something which cannot have proceeded from me myself. By the name of God I understand a substance that is infinite [eternal, unchangeable], independent, all-knowing, all-powerful, and by which I myself and everything else, if anything else does exist, has been created. Now all these characteristics are such that the more diligently I attend to them, the less do they appear capable of proceeding from me alone; hence, from what has been already said, we must conclude that God necessarily exists. Descartes's position amounts to this: I have in me the clear and distinct idea of a perfect, infinite being. Where could I, an imperfect, finite creature, ever get the idea of infinite perfection? A perfect being is not just a bigger, stronger, quantitatively improved Descartes. If my idea of God were merely of a kind of superhuman being, then I might have created it out of wishful thinking. But how could I even have a notion of infinite perfection, or want to be more perfect myself, "unless I had within me some idea of a Being more perfect than myself, in comparison with which I should recognize the deficiencies of my nature?" In other words, because of its very uniqueness, the idea of an infinite, perfect being must come from just such a being: God. Note that Descartes has ruled out the idea of an infinite regress of causes. He is also appealing to a version of the principle of sufficient reason (Chapter 8). No matter how far the chain of causes extends, nothing is sufficient to explain (cause) the idea of a perfect, infinite being but a perfect, infinite being: Does your idea of God include a body, a gender, a location like those in this eighteenth-century engraving by Julius Schnorr von Carolsfeld? If you have any specific ideas of God's properties, are they "perfect" ideas of perfect properties? Ivan Burmistrov/iStockphoto.com And although it may be the case that one idea gives birth to another idea, that cannot continue to be so indefinitely; for in the end we must reach an idea whose cause shall be so to speak an archetype, in which the whole reality [or perfection] which is so to speak objectively [or by representation] in these ideas is contained formally [and really]. Thus the light of nature causes me to know clearly that the ideas in me are like [pictures or] images which can, in truth, easily fall short of the perfection of the objects from which they have been derived, but which can never contain anything greater or more perfect. In other words, Descartes's mind cannot be the cause of this one special idea. If Descartes were the cause of Descartes, then he would have given himself all the perfections associated with God. So ultimately something other than Descartes must be its cause. The same is true of any so-called evil geniuses or angels or other not-perfect, finite beings. Descartes, for all his dislike of Scholastic philosophy, follows a Scholastic line in his analysis of these matters. He seems to be saying that not only is God a perfect being, but the idea of God is also a "perfect idea." If it is, he reasons, where could it come from? Imperfect creatures such as ourselves can imagine only imperfect ideas; we could not come up with the idea of a perfect anything without help. Where could the idea of perfection come from? Only from a mind more perfect than ours: It is perfectly evident that there must be at least as much reality in the cause as in the effect; and thus since I am a thinking thing, and possess an idea of God within me, whatever in the end be the cause assigned to my existence, it must be allowed that it is likewise a thinking thing and that it possesses in itself the idea of all the perfections I attribute to God. ... But if it derives its existence from some other cause than itself, we shall again ask, for the same reason, whether this second cause exists by itself or through another, until from one step to another, we finally arrive at an ultimate cause, which will be God. Descartes determines that he cannot have "received" the idea of God through the senses, nor has it suddenly burst upon his consciousness. He cannot have imagined it, for he lacks the ability to improve upon or to detract from it. Consequently, he says, "the only alternative is that it is innate in me, just as the idea of myself is innate in me." Descartes's conception of God as a perfect being includes the qualities of all-knowing, all-powerful, all-loving, all-good. Descartes posits that such a God would not let him be constantly deceived by either himself or some evil genius. If, the argument goes, God gave us reason and faculties of perception, they must be basically accurate and reliable. God's existence is crucial to the Cartesian Genesis: And the whole strength of the argument which I have here made use of to prove the existence of God consists in this, that I recognize that it is not possible that my nature should be what it is, and indeed that I should have in myself the idea of a God, if God did not veritably exist—a God, I say, whose idea is in me, i.e., who possesses all those supreme perfections of which our mind may indeed have some idea but without understanding them all, who is liable to no errors or defect [and who has none of all those marks which denote imperfection]. From this it is manifest that He cannot be a deceiver, since the light of nature teaches us that fraud and deception necessarily proceed from some defect.

From Cosmos to Machine

As noted in Chapter 2, ancient Greek philosophy developed in a series of increasingly abstract steps, until growing concern with logical consistency and rules of thinking led to theories that, though logically consistent, did not match observed facts. One result of this split between common experience and the claims of early philosophers was the alienation of philosophy from the life concerns of most people. Historian of philosophy Amaury de Riencourt says, "The absolute predominance of the dissociating, analytical masculine principle in Greek thought is obvious—hence its strength and its weakness." As the early Greeks developed and refined rational skills, they increasingly valued personal detachment and the suppression of traits that today we associate with maternal and caring qualities. Objectivity and emotional detachment—qualities traditionally associated with masculinity—were considered essential aspects of knowledge, and subjectivity and emotional involvement were considered hindrances. According to feminist philosopher of culture Susan Bordo (b. 1947), this "masculinizing" of philosophical thought reached a watershed at the beginning of the modern period. In "The Cartesian Masculinization of Thought," Bordo argues that "Cartesian modernity is inherently linked to the repression of nature and women." This repression, she suggests, is motivated by revulsion and uneasiness that modernity has traditionally associated with the daily lives of women. Women's lives are circumscribed by menstruation, childbirth, nursing, caring for others. In short, women's experiences are embodied experiences that cannot be abstracted into distinct mental and physical substances. Bordo's point is that the daily lives of women do not reflect Cartesian dualism. Susan Bordo Bordo's critique of modern philosophy adds a feminist perspective to the radical sorts of criticisms brought to bear on objectivity and rationality by Marx, Kierkegaard, James, and Nietzsche. (See Chapters 13-16.) According to Bordo, modernity rests on Descartes's attempt to reconstruct the world based solely on his own clear and distinct ideas. She says, "We are all familiar with the dominant Cartesian themes of starting anew, alone, without influence from the past or other people, with the guidance of reason alone." The result, Bordo argues, is that objectivity, rather than meaning, became the chief philosophical issue. But as long as human beings are "embedded in nature," embodied and subject to its rhythms, such detachment is impossible. If a kind of Cartesian ideal were ever completely fulfilled, i.e., if the whole of nature were only what can be explained in terms of mathematical relationships—then we would look at the world with that fearful sense of alienation, with that utter loss of reality with which a future schizophrenic child looks at his mother. Amachine cannot give birth. — Karl Stern In Bordo's view, Descartes's particular genius was the way in which he laid a philosophical foundation for transforming the initial experience of alienation and loss that accompanied the Copernican Revolution into an optimistic, objective method for understanding, dominating, and managing nature. (See the Overview of Modern Themes.) According to Bordo, Cartesian rationalism required sundering the organic ties between the person (subject) and the world (object). As Bordo sees it, starting with Descartes, modern philosophy reacted to the new cosmic order with an exaggerated emphasis on objectivism and mechanism. As a result, the modern vision of the universe is one of a complex machine, not an organic whole (cosmos): This re-visioning of the universe as a machine—most often, a clockwork—was not the work of philosophers alone. Astronomy and anatomy had already changed the dominant picture of the movements of the heavens and the processes of the body by the time the Meditations were written. But it was philosophy . . . that provided the cosmology that integrated these discoveries into a consistent and unified view of nature. ... Nature became defined by its lack of affiliation with divinity, with spirit. All that which is god-like or spiritual—freedom, will, and sentience—belong entirely and exclusively to res cogitans [the thing that thinks]. All else—the earth, the heavens, animals, the human body—is merely mechanically interacting matter. Bordo goes on to suggest that the masculinization of science involves more than just the historical fact of male dominance of the sciences, noting that "the most interesting contemporary discussions of the 'masculinist' nature of modern science describe a . . . characteristic cognitive style, an epistemological stance which is required of men and women working in the sciences today." Bordo does not, however, see modernity as entirely negative: Inspired by the work of [Carol] Gilligan, [Nancy] Chodorow, [Susan] Harding, and [Evelyn Fox] Keller, feminist theory has been systematically questioning the historical identification of rationality, intelligence, "good thinking," and so forth, with the masculine modes of detachment and clarity, offering alternative models of fresher, more humane, and more hopeful approaches to science and ethics.

Innate Ideas

As you wrestle with these issues, keep in mind that getting started is the most difficult part of establishing a new or original philosophical orientation. We must begin with initially unquestioned assumptions and basic principles. To a certain extent, some ideas must be known before we can know anything else. These ideas must be first or occur prior to knowing everything else. A priori ideas are characterized as being certain, deductive, universally true, innate, or independent of all experience. A priori knowledge is derived from reason without reference to sense experience. Truths of reason and laws of logic are usually thought to be a priori. Examples include "All triangles contain 180°" and "Every event has a cause." In contrast to a priori knowledge, a posteriori knowledge is empirical knowledge derived from sense experience. This kind of knowing comes from the accumulation of experience. It is not regarded as certain or necessary, because the conditions under which it is acquired change, perceivers vary, and factual relationships change. For example, the statement "My shirt is white" can be true for a particular set of circumstances today and false tomorrow. "My shirt is white" is not universally or eternally true in the way that "Every event has a cause" is. A posteriori truths are also called factual truths or truths of fact, as opposed to rational truths. (Not all philosophers agree that a priori truths exist. For example, the empiricists, whom we will meet in Chapter 10, insist that all knowledge comes from sense experience.) As a brilliant geometer, Descartes was familiar with the axioms for geometric proofs, which he characterized as a priori ideas. He believed we are born with certain ideas "implanted" in us by God. For example, we are born with the idea of a triangle in our minds. When we see triangles or triangular-shaped objects, we are reminded of this innate idea. Descartes often appeals to the standard of clarity and distinctness as if its truth should be obvious to us with a bit of reflection. All we need is to be "reminded" of it to recognize its truth. Philosophical Query Is Descartes correct? What about seemingly sincere, rational, and intelligent people who say they do not, perhaps cannot, see the truth of this idea about innate ideas? Compare Descartes's problem here with Plato's problem of accounting for ignorance of the Forms. Do you think Forms are innate ideas? Are innate ideas Forms? (See Chapter 5.)

Chapter Introduction

By the seventeenth century, developments in modern science, combined with a decline in the authority of a single (Roman Catholic) church, signaled the end of the medieval era and the beginning of what we now refer to as the modern worldview. In philosophy, the result of these changes was a shift away from metaphysics toward epistemology. As remarkable as it may seem, René Descartes was the first philosopher to study the process of thinking itself. In so doing, he began what philosophers refer to as the epistemological turn, a major transformation in the character of philosophy that would ultimately require a century and a half to complete, culminating with Immanuel Kant's Critique of Pure Reason (Chapter 11). Whereas earlier philosophers sought knowledge about the good life, nature, the soul, God, the ideal society, and so forth, from Descartes forward, modern philosophers increasingly devoted themselves to acquiring knowledge about knowledge. The power of Descartes's original insight becomes clear once it is articulated: Before we can reasonably evaluate any beliefs about reality, we must inquire into the nature of the "instrument" we use to observe it.

Cogito, Ergo Sum

Could the evil genius so arrange things that nothing is as I think it is? In the physical realm, he could. He could trick me into thinking that I have a body when I don't, that things have shapes, colors, and so on that they really don't. Descartes says that—as difficult as it is to imagine—he might even be able to deceive me regarding certain innate, a priori, ideas so that maybe 7 + 5 does not really equal 12 or triangles don't have three sides. If I can be tricked into thinking things exist that do not exist, and if I can be fooled into thinking things do not exist when they really do, then maybe I am being deceived about my own existence. Is there anything the evil genius cannot trick me about? Maybe I don't really exist? Frank and Ernest reprinted by permission of Bob Thaves. Not at all; of a surety I myself [must] exist since I persuaded myself of something [or merely because I thought of something]. But [what if] there is some deceiver or other, very powerful and very cunning, who ever employs his ingenuity in deceiving me. Then without doubt I exist also if he deceives me, and let him deceive me as much as he will, he can never cause me to be nothing so long as I think that I am something. So that after having reflected well and carefully examined all things, we must come to the definite conclusion that this proposition: I am, I exist, is necessarily true each time that I pronounce it, or that I mentally conceive it. This is the famous "cogito," from the Latin sentence , meaning I think, therefore I am. In some ways, this Cartesian insight, more than anything else, marks the beginning of the modern worldview. Note the difference between "Descartes thinks, therefore Descartes exists" and "I think, therefore I exist," where the "I" refers to whoever speaks or thinks the sentence. The cogito must be understood in the first person. In that form, it meets Descartes's conditions for being utterly unshakable. No rational person can doubt his or her own existence as a conscious thinking entity—while being aware of thinking about anything. Hamlet did think a great many things; does it follow that he existed? — Jaako Hintikka Descartes interprets this to mean that while bodily existence may seem more solid and certain than ideas, mental existence is in actuality more certain. He goes on: I find here that thought is an attribute that belongs to me; it cannot be separated from me. I am, I exist, that is certain. But how often? . . . to speak accurately [at this stage of the Meditations] I am not more than a thing which thinks, that is to say a mind or soul, or an understanding, or a reason, which are terms whose significance was formerly unknown to me. I am . . . a real thing and really exist; but what thing? I have answered: a thing which thinks. . . . What is a thing which thinks? It is a thing which doubts, understands, [conceives], affirms, denies, wills, refuses, which also imagines and feels. Descartes argues that we identify and know everything—including bodily and material things—through the mind. He grounds all knowledge in mental states, in awareness. Thus the foundation of Descartes's philosophy and, to a considerable extent, of the modern worldview is the thinking self. Although Descartes was a rationalist, the thrust of the cogito is not reasoning but self-awareness. Augustine had a similar formula: "I doubt, therefore I am," and in Nausea Jean-Paul Sartre wrote, in effect, "I am nauseated, therefore I exist." "Quod Si Fallor, Sum: If I Am Mistaken, I Exist" More than twelve centuries before Descartes's attempt to refute skepticism with the certain knowledge of his own existence (the cogito), Augustine (Chapter 8) used a remarkably similar argument for the same purpose in The City of God: The certainty that I exist, that I know it, and that I am glad of it, is independent of any imaginary and deceptive fantasies. In respect of these truths I have no fear of the arguments of the [Skeptics]. They say, "Suppose your arguments are mistaken?" I reply, "If I am mistaken, I exist." A non-existent being cannot be mistaken; therefore I must exist, if I am mistaken. . . . Since therefore I must exist in order to be mistaken, then even if I am mistaken, there can be no doubt that I am not mistaken in my knowledge that I exist. It follows that I am not mistaken in knowing that I know. And when I am glad of those two facts, I can add the fact of that gladness to the things I know, as a fact of equal worth. For I am not mistaken about the fact of my gladness, since I am not mistaken about the things which I love. Even if they were illusory, it would still be a fact that I love the illusions. Augustine, The City of God, trans. Henry Bettenson (Harmonds-worth, England: Penguin, 1972), 11.26. So far, Descartes has established that the thinking thing possesses absolute certainty of its own existence as a consciously thinking thing. Thus there is one rather limited fact I know with certainty. Do any other insights follow from this bedrock experience of self-consciousness? Can Descartes move from it to re-create the external world?

The Innate Idea of God

Descartes begins the third Meditation still treating everything he thinks of as part of himself, as merely "perceptions and imaginations" from his own mind. That being so, his next step is to survey his own thoughts, to see whether there might be something he has overlooked or been unaware of so far. He reasons that the most important issue is the existence of God: I must inquire whether there is a God as soon as the occasion presents itself; and if I find that there is a God, I must also inquire whether He may be a deceiver; for without a knowledge of these two truths I do not see that I can ever be certain of anything. In other words, if Descartes can establish the existence of God rationally, he will have a foundation for truth concerning other ideas. If God is not an evil deceiver, Descartes argues, He will have created the reasoning mind to seek and know the truth. Rationally verifying the existence of God will not only guarantee the possibility of knowledge with certainty but also bridge the gaps between religion and science and between the imagination and reality. If God is the source of reason, then it follows that He wills the use of reason in pursuit of truth. If so, then God is the impetus behind science. If God is not a deceiver, then He will have given Descartes the ability to distinguish the real from the merely imagined. Thus the issue of God's existence and nature is crucial to Descartes's entire rationalistic enterprise.

The Method of Doubt

Descartes believed that a mathematically precise method is the only reliable way to discover the truth about the universe. He proposed to use the new spirit of scientific inquiry and mathematical rigor to reexamine everything! His effort not only marks the beginning of an entirely new philosophical orientation but also remains fascinating and relevant. In order to reach a wider audience of European intellectuals, Descartes wrote in everyday French rather than in Latin, the "universal language of scholars." Time & Life Pictures/Getty Images Descartes attacked earlier philosophy on the grounds that it did not demand rational comprehension from the individual intellect. It did not rest solely on ideas known through "the clear light of natural reason": I thought that the sciences found in books—and those at least whose reasonings are only probable and which have no demonstrations, composed as they are of the gradually accumulated opinions of many different individuals—do not approach so near to the truth as the simple reasoning which a man of common sense can quite naturally carry out respecting the things which come immediately before him. "Common sense," which Descartes also referred to as natural reason, is the ability to think that is found in all normal humans. It does not depend on divine revelation or formal education—at least according to Descartes. Though not everyone has the talent for or interest in refined thinking, Descartes believed all reasoning individuals could apply his method to basic questions concerning human nature, truth, and the existence of God: Good sense is of all things in the world the most equally distributed, for everybody thinks himself so abundantly provided with it, that even those most difficult to please in all other matters do not commonly desire more of it than they already possess. It is unlikely that this is an error on their part; it seems rather to be evidence in support of the view that the power of forming a good judgment and of distinguishing the true from the false, which is properly speaking what is called Good Sense or Reason, is by nature equal in all men. Hence too it will show that the diversity of our opinions does not proceed from some men being more rational than others, but solely from the fact that our thoughts pass through diverse channels and the same objects are not considered by all. For to be possessed of good mental powers is not sufficient; the principal matter is to apply them well. The greatest minds are capable of the greatest vices as well as of the greatest virtues, and those who proceed very slowly may, provided they always follow the straight road, really advance much faster than those who, though they run, forsake it. Philosophical Query Comment on the preceding passage. Do you agree with Descartes? Why? Is common sense the same thing as good sense? Analyze the notion of common sense. Do you really think there is such a thing? What is your evidence either way?

The Cartesian Bridge

Descartes was a devout Catholic who took his religion seriously. He was aware of the challenge to religion posed by advances in physics and astronomy and the reemergence of materialism (also known as behaviorism, mechanism, or reductionism). Other philosophers, most notably Thomas Hobbes (1588-1679), were arguing that everything is composed of matter (and energy) and can be explained by physical laws. This means all human activity can be understood as the natural behavior of matter according to mechanical laws. Thus, thinking is merely a complex form of behaving, and the body is a fleshy machine. The so-called mind can be reduced to the brain, and thinking and acting can be reduced to biochemical brain states and stimulus-response reactions. Since the laws of physics are universal, there can be no such thing as a free will. If everything is material, there can be no such thing as an immaterial soul. (This point of view, which is held by many scientists and philosophers today, will be discussed more fully in Chapter 10.) Like the theologians, Descartes was alarmed by the amoral, secular nature of this particular view of the universe. Yet, as we have noted, he was a scientist himself, and his philosophy was designed to bridge the growing gap between the "new science" and religion. By showing that the mind is different in kind from the body, Descartes hoped to prove that the discoveries of the physicists posed no threat to free will or the existence of an incorporeal soul. The laws of physics apply only to matter, but the mind (soul) is an incorporeal thinking substance. Mind and body are two completely different kinds of substances. Thus, science turns out to be the language of bodies; it cannot address minds or souls, so it is no threat to the church or basic Christian theology.

he Cartesian Genesis

Descartes' success is indicated by the extent to which the central notions of his philosophy became the common conception of man and the universe for nearly three centuries. — Alexander Sesonske and Noel Fleming To summarize: Descartes wanted to find an absolutely certain, indubitable starting point for his philosophy. He chose a form of deliberate, methodological skepticism that we have labeled methodic doubt. As we will see from the work of David Hume (Chapter 10), there are degrees of skepticism, progressing from total doubt about everything to temporary or particular doubt invoked just for the process of analysis. Descartes's skepticism is part of his method and is, consequently, of the temporary—but still serious—sort. He does not really doubt everything he challenges in his Meditations; rather, systematically doubting is the process of Cartesian inquiry, not the end result. Descartes hoped to use skepticism to establish complete certainty. Consciousness is a disease. — Miguel de Unamuno In the Meditations, Descartes begins by asking if it is rationally possible to doubt everything. He reasons that by doing this, he will quickly discover if there is any certain, undoubtable truth. In the course of this inquiry, Descartes tears down the old world of Scholastic philosophy, unquestioned beliefs, and ambiguous ideas and attempts to replace it with a brand-new, certain, clearly proved, rational order. He suggests that his readers reflect on one meditation a day, reading carefully and leisurely. After six days, Descartes, like God in the biblical book of Genesis, will have finished with his own creation. The attentive, rational reader, by becoming the Cartesian "I" in the manner noted earlier, will also have torn down and rebuilt his or her previously unquestioned house of beliefs on a solid, rational foundation. Descartes begins the Meditations by giving his methodic doubt the widest possible scope. He calls Meditation I Of the things which may be brought within the sphere of the doubtful. In the first two paragraphs, Descartes invokes the skeptical method and introduces the standard of clarity and distinctness and immediately points out that it would be impossible to examine every belief he currently holds. Instead, he will examine the origins and foundations of basic kinds of beliefs. If there is any possibility, however remote, that they could be mistaken, Descartes will reject them and every idea that depends on them: It is now many years since I detected how many were the false beliefs that I had from my earliest youth admitted as true, and how doubtful was everything I had since constructed on this basis; and from that time I was convinced that I must once and for all seriously undertake to rid myself of all the opinions which I had formerly accepted, and commence to build anew from the foundation if I wanted to establish any firm and permanent structure in the sciences. ... Now for this object it is not necessary that I should show that all of these are false—I shall perhaps never arrive at this end. But inasmuch as reason already persuades me that I ought no less carefully to withhold my assent from matters which are not entirely certain and indubitable than from those which appear to be manifestly false, if I am able to find in each some reason to doubt, this will suffice to justify my rejecting the whole. And . . . owing to the fact that the destruction of the foundations of necessity brings with it the downfall of the rest of the edifice, I shall only in the first place attack those principles upon which all my former opinions rested. Philosophical Query How carefully have you examined your own fundamental beliefs? What—if anything—is wrong with trusting beliefs handed down by others? Why not rely on the testing of others, trusting their conclusions? Also consider the widespread tendency to believe something if it could possibly be correct. What is the relationship between possible and plausible, and what might it have to do with this entire issue? Explain.

Against Disorganized Thinking

Descartes's first philosophical work was Rules for the Direction of the Mind. The twenty-one principles contained in Rules reappear in Descartes's major philosophical works, Discourse on Method and Meditations on First Philosophy. Rule 3 advises: Once we have chosen a subject to study, we should confine ourselves to what we can clearly intuit and deduce with certainty for ourselves. We must not rely on what others have thought or on our own as-yet-untested beliefs. We must look for ourselves, with new eyes and new understanding. Referring to the Scholastics, among others, Descartes cautions that "in a too absorbed study" of the works of earlier thinkers, we become "infected with their errors, guard against them as we may." This is a general caution against authoritarian thinking, in which we give more weight to the opinions of others than to our own experience and clear thinking. When we accept views solely on the weight of the authority or prestige of those who hold them, or because of loyalty to a cause or belief structure, we become nonrational at best. We become memorizers, not thinkers. "Beyond Intellect There Is Yet Another Stage" In 1091, the Persian philosopher Abu Hamid Muhammad al-Ghazali (1058-1111) was appointed professor of Islamic theology at the Nizamiyah College in Baghdad. In 1095, al-Ghazali, by then a man of great influence, suffered a spiritual crisis and nervous breakdown that resulted in a speech impediment that prevented him from lecturing. He left the college and ultimately embraced a mystical form of Islam known as sufism. Al-Ghazali briefly returned to teaching but eventually quit for good and founded a monastic community in Tus, the city of his birth. The passage that follows is from his work The Deliverance from Error. Note how al-Ghazali's work anticipates Descartes's first meditation by five hundred years. Whereas Descartes exalted reason over faith, al-Ghazali "transcended" reason with the mystic's direct and immediate experience of God (Allah). To thirst after a comprehension of things as they really are was my habit and custom from a very early age. ... as I drew near the age of adolescence the bonds of mere authority . . . ceased to hold me and inherited beliefs lost their grip upon me, for I saw that Christian youths always grew up to be Christians, Jewish youths to be Jews and Muslim youths to be Muslim. ... I therefore said within myself: "To begin with, what I am looking for is knowledge of what things really are, so I must undoubtedly try to find what knowledge really is." It was plain to me that sure and certain knowledge is that knowledge in which the object is disclosed in such a fashion that no doubt remains along with it, that no possibility of error or illusion accompanies it, and that the mind cannot even entertain such a supposition. Certain knowledge must also be infallible. ... Thus, I know that ten is more than three. Let us suppose that someone says to me: "No, three is more than ten, and in proof of that I shall change this rod into a serpent": and let us suppose that he actually changes the rod into a serpent and that I witness him doing so. No doubts about what I know are raised in me because of this. The only result is that I wonder how he is able to produce this change. Of doubt about my knowledge there is no trace. After these reflections I knew that whatever I did not know in this fashion and with this mode of certainty is not reliable and infallible knowledge; and knowledge that is not infallible is not certain knowledge. ... Thereupon I investigated the various kinds of knowledge I had, and found myself destitute of all knowledge with this characteristic of infallibility except in the case of sense-perception and necessary truths. ... I proceeded therefore with extreme earnestness to reflect on sense-perception and on necessary truths, to see whether I could make myself doubt them. The outcome of this protracted effort was that I could no longer trust sense-perception either. ... . . . "Do you not see," [my ego] said, "how, when you are asleep, you believe things and imagine circumstances, holding them to be stable and enduring, and, so long as you are in that dream-condition, have no doubts about them? . . . Why then are you confident that all your waking beliefs, whether from sense or intellect, are genuine? They are true in respect of your present state; but it is possible that a state will come upon you whose relation to your waking consciousness is analogous to the relation of the latter to dreaming. In comparison with this state your waking consciousness would be like dreaming! When you are in this state, you will be certain that all the suppositions of your intellect are empty imaginings. ... " It became clear to me . . . that what is most distinctive about mysticism is something which cannot be apprehended by study, but only by immediate experience . . . by ecstasy and by a moral change. What difference between knowing the definition ofhealth and satiety . . . and being healthy and satisfied! . . . Beyond intellect there is yet another stage. In this another eye is opened, by which he beholds the unseen, what is to be the future, and other things which are beyond the ken of intellect. Abu Hamid Muhammad al-Ghazali, The Deliverance from Error, in The Faith and Practice of Al-Ghazali, trans. W. Montgomery Watt (London: George Allen and Unwin, 1953), pp. 21-68. Descartes points out that it is common to overlook clear, simple truths (intuitions) when we do encounter them. We quickly complicate them with cloudy but elaborate "explanations." He speculates that we surround the truth with ambiguities because we are afraid that the simplicity of our discoveries will make them seem unimportant. He adds: For we shall not, e.g., turn out to be mathematicians though we know by heart all the proofs others have elaborated, unless we have an intellectual talent that fits us to resolve difficulties of any kind. Neither, though we may have mastered all the arguments of Plato and Aristotle, if yet we have not the capacity for passing solid judgment on these matters, shall we become Philosophers; we should have acquired the knowledge not of a science, but of history. Philosophical Query Use Descartes's distinction between memorizing ideas and understanding them to examine your own education. Describe the distinction between learning to love psychology or literature and becoming a historian of psychology or literature, in Descartes's terms. Speculate on ways this distinction might be used to reform education. Addressing the fact that we are bombarded with conflicting knowledge claims, Rule 4 succinctly states: There is need of a method for finding the truth. I shall not say anything about Philosophy, but that, seeing that it has been cultivated for many centuries by the best minds that have ever lived, and that nevertheless no single thing is to be found in it which is not the subject of dispute, and in consequence which is not dubious. — René Descartes So blind is the curiosity by which mortals are possessed, that they often conduct their minds along unexplored routes, having no reason to hope for success. ... it were far better never to think of investigating truth at all, than to do so without a method. For it is very certain that unregulated inquiries and confused reflections of this kind only confound the natural light and blind our mental powers. ... In [method] alone lies the sum of all human endeavour, and he who would approach the investigation of truth must hold to this rule. A scientist with a Ph.D. in physical chemistry is questioned by the members of the Kansas State Board of Education about teaching evolution. What expertise is required to evaluate his claims? Larry W. Smith/Getty Images For Deeper Consideration Descartes says that "it were far better never to think of investigating the truth at all, than to do so without a method." Why was he so troubled by disorganized thinking and blind curiosity? What do you think he might say to us about basing our opinions regarding climate change, creation versus evolution, gun control, sexual identity, balancing the federal budget, the Constitution, and other controversial matters on what we "learn" from movies, TV, the Internet, bloggers, politicians, and even our professors? What methods do you use to choose among competing "experts" and positions? Is Descartes suggesting that we must become experts in choosing experts? Or is he arguing for something else entirely, and if so, what and why?

Commentary

Descartes's rationalism was inspired by a vision and three dreams, which he interpreted as a divine calling to establish his method of rational inquiry. Through the innovative use of methodic doubt, he established one irrefutable certainty, the cogito. Descartes claimed that God's existence was the foundation for all knowledge and for the general reliability of the "natural light" of reason, yet, for the contemporary observer, the cogito is more solidly grounded than the proof for God. To a considerable extent, the modern era is grounded in Cartesian self-consciousness, self-reflection, and self-analysis. In its emphasis on an individual's inquiry after truth rather than official answers, Cartesian rationalism seems to pave the way for social and political democracy. The irony in this is that we note a kind of cool, analytic detachment as Descartes makes himself the subject of study in a new way. As the modern era develops, purity of method ultimately takes precedence over the search for wisdom. This trend might be a consequence of the detached, depersonalized quality of rationalistic analysis that emerged in the work of Descartes. The benefits of the Cartesian revolution include the use of clearer, simpler, ordinary language (an idea that significantly influenced subsequent philosophers). Descartes paved the way for psychological studies by showing that the "thinking thing" is not a neutral "window" but a dynamic entity whose very nature affects its observations and conclusions. He initiated the study of knowledge and the sources of knowledge that continues to this day. Even the rationalists' great epistemological opponents, the empiricists, found themselves responding partly to issues raised by rationalism. Unlike others of his time (and ours), Descartes refused to bow before authority, choosing to accept only what he knew for himself. He stands out as an archetype of the rationalist for his unwillingness to settle for inconsistencies and contradictions between his faith and his intellect. If his notion of "clear and distinct" is itself cloudy, if his introduction of God is suspicious, and if his attempt to account for mind-body interaction is unsatisfying, he is nonetheless remarkable for squarely facing up to the need to reassess his belief system for himself. Descartes tried not to believe what he could not clearly understand. That in itself is a remarkable achievement.

Summary of Main Points

Descartes's scientific and mathematical interests demanded clear, provable evidence of a sort lacking in Scholasticism's cumbersome reliance on authority and resulted in a radical proposal: Start fresh; throw out everything we think we know and build a system based entirely on ideas whose truth can be clearly and distinctly known to us firsthand. Rationalists rely on the coherence theory of truth: New or unclear ideas are evaluated in terms of rational or logical consistency and in relation to already established truths. Reliance on reason as the ultimate source of knowledge is a form of rationalism, the notion that abstract reasoning can produce absolutely certain truths about reality and that some important ultimate truths can be discovered without observation, experiment, or experience. Such truths are known as innate ideas or a priori ideas. Ideas derived from experience are known as a posteriori ideas. Descartes's interest in the "thinking thing itself" was the first major step in a shift in emphasis in modern philosophy from metaphysics to epistemology. He recognized the need for orderly thinking, which he called method. This paved the way for the modern emphasis on technique (method) and marks a major change from metaphysical, authoritarian medieval thinking to epistemological, technical modern thinking. Descartes employed methodic doubt in his effort to find one absolutely certain and undoubtable idea. Methodic doubt is a form of skepticism that rejects any idea that could possibly be false, no matter how remote that possibility. Methodic doubt coupled with the concept of the evil genius led Descartes to raise questions about whether or not he was dreaming and about the existence of his own body and of the entire external world. Even an evil genius could not shake one fundamental idea: "I think, therefore I am." This is known as the cogito. Having found an undoubtable truth, Descartes tried to build a reliable foundation for knowledge on the innate idea of God. He did this by appealing to an argument that attempts to prove the existence of God by showing that the idea "God" cannot be derived from human experience; it can only come from the actual existence of God. Having established the existence of God to his satisfaction, Descartes believed he had clearly and distinctly demonstrated the reliability of reason and the possibility of certain knowledge, since if God is all-knowing, all-good, and all-powerful, He would not let us live in constant ignorance. Descartes rejected the materialists' challenge to the notion of free will with Cartesian dualism, the belief that two completely different kinds of things exist, bodies and minds, and that human beings are a mysterious union of both. Dualism, however, generates the mind-body problem: What is the relationship of the mind to the body? How can a nonmaterial thing (mind) affect a material thing (body)? According to Susan Bordo, a "masculinizing" of modern philosophical thought reached a watershed at the beginning of the modern period. Bordo asserts that Cartesian modernity is inherently linked to the repression of both nature and women. Bordo argues that the daily lives of women do not reflect Cartesian dualism because women's experiences are embodied experiences that cannot be abstracted into distinct mental and physical substances.

The Mind-Body Problem

Dualism generates one of the most tenacious of philosophical questions: What is the relationship of the mind to the body? Yet so appealing is dualism to philosophers, preachers, psychologists, and most of the rest of us that in his influential and controversial book The Concept of Mind, contemporary philosopher Gilbert Ryle refers to it simply as "the official doctrine." Ryle says: The official doctrine, which hails chiefly from Descartes, is something like this. With the doubtful exceptions of idiots and infants in arms every human being has both a body and a mind. Some would prefer to say that every human being is both a body and a mind. His body and his mind are ordinarily harnessed together, but after the death of the body his mind may continue to exist and function. Corollaries of the official doctrine are found in beliefs about the immortality of the soul and reincarnation. Corollaries are implicit in psychological theories that view the mind as something other than the brain and that differentiate mental states from bodily conditions and behavior. The official doctrine is reflected in ordinary language when we talk about having a body and in common experience when we feel as if "we" are somehow in our bodies. Religious and metaphysical versions of the official doctrine sometimes compare the soul to a driver and the body to a car. At death, we get out of the car or—if you believe in reincarnation—trade in the old body for a new one. Descartes rejects the car-driver type of analogy and unites mind and body into "one whole": Nature also teaches me by these sensations of pain, hunger, thirst, etc., that I am not only lodged in my body as a pilot in a vessel, but that I am very closely united to it, and so to speak so intermingled with it that I seem to compose with it one whole. For if that were not the case, when my body is hurt, I who am merely a thinking thing, should not feel pain, for I should perceive this wound by the understanding only, just as a sailor perceives by sight when something is damaged in his vessel; and when my body has need of drink or food, I should clearly understand the fact without being warned of it by confused feelings of hunger and thirst. For all these sensations of hunger, thirst, pain, etc., are in truth none other than certain confused modes of thought which are produced by the union and intermingling of mind and body. "Darrow's Trip to Goofville" If I am told that next week I shall start on a trip to Goofville; that I shall not take my body with me; that I shall stay for all eternity: can I find a single fact connected with my journey—the way I shall go, the part of me that is to go, the time of the journey, the country I shall reach, its location in space, the way I shall live there—or anything that would lead to a rational belief that I shall really take the trip? Have I ever known anyone who has made the journey and returned? If I am really to believe, I must try to get some information about all these important facts. Clarence Darrow, "The Myth of the Soul," The Forum 80 (October 1928). A sketch from Descartes's Treatise on Man depicting brain function and the anatomy of the eyeball. According to Descartes, the pineal gland (H) is the crucial link between mind and body. Archive/Getty Images (The "union" or "intermingling" occurs, as noted earlier, in the pineal gland. Descartes apparently devoted some time to dissecting animal carcasses in order to study this mysterious gland.) Dualism feels consistent with certain common experiences but inconsistent with others: If I hit my thumb with a hammer, I experience no mind-body split. Yet there are serious consequences if we reject dualism in favor of a materialistic, behavioristic monism: When we reduce mental states to physical states, do we lose the possibility of free will, moral responsibility, and the possibility of survival after death? Such beliefs are important to the very meaning of life for many people, real enough and important enough so that any difficulties of explaining mind-body interaction pale beside the consequences of rejecting dualism. But the fact that millions of people believe something does not make it true. Cartesian dualism—indeed, metaphysical speculation itself—stands in direct opposition to another major modern philosophical archetype: the skeptical questioner who turns to experience rather than to the mind for knowledge. The skeptic is the subject of Chapter 10. Chapters 14-18 deal with existential and postmodern rejection of abstract metaphysics. Philosophical Query How plausible is this "official doctrine"? On Descartes's own terms, how "clearly and distinctly" do we understand the relationship of the mind to the body? How can a completely nonphysical thing interact with a completely physical thing? To ask Mark Twain's insightful question, How come the mind gets drunk when the body does the drinking? Why does my mind react to what happens to my body with such intensity if it's not part of my body?

The Cartesian "I" and Methodic Doubt

For those who like a dramatic and specific date, the simple but far-reaching phrase of Descartes, "I think, therefore I am" will do very well for the beginning [of the Age of Reason]: 1657. — Crane Brinton Descartes did not write in Latin, the "universal language of scholars," but in everyday French. His aim was to reach beyond the confines of the university and church to a wider audience of European intellectuals. Consequently, Descartes cast all his works in the first person to describe both his conclusions and his thinking process. He wanted to call our attention to the actively reasoning mind itself. Until Descartes, philosophers tended to focus on the content of ideas and on their logical relations to each other, not on the mind. Although "reason" was discussed and referred to, and often cited as the guide by which we should live, the "reasoning thing" itself was not directly studied. As you study Descartes's ideas, don't always interpret the "I" as referring to Descartes; allow it also to refer to you while you are reading (and, I hope, thinking along with) the words Descartes wrote. By occasionally becoming the "I" yourself, you can participate in the conscious flow of Descartes's reasoning in a way that will help you evaluate his arguments as if they were your own. You will be reflecting and meditating on your own conscious mind. Descartes was convinced that he could apply a mathematically oriented method to the most fundamental problem of all: How can I know that I know anything? In geometry, he pointed out, we begin with self-evident truths such as "A straight line is the shortest distance between two points." More complex theorems based on these truths are then called upon to prove less-evident truths. Descartes proposed applying this basic method to philosophy. In his Rules, he stated that we must not accept anything we can doubt at all. In his effort to base his philosophy on an absolutely certain foundation, Descartes had a culture-altering insight. He discovered methodic doubt. Simply put, methodic doubt involves deliberately doubting everything it is possible to doubt in the least degree. Whatever remains will be known with absolute certainty. In order to apply methodic doubt, Descartes had to rely on a standard of truth that could tell him whether it was reasonable to doubt something.

Reconstructing the World

Having shown that at least one mind (his own) and God exist, Descartes concludes his project by reestablishing knowledge of the objective existence of the external world: Nothing further now remains but to inquire whether material things exist. ... And certainly I at least know that these may exist. ... For there is no doubt that God possesses the power to produce everything that I am capable of perceiving with distinctness. Descartes reasons that since he has a clear and distinct idea of himself both as a mind and as having a body, he must of necessity be both a mind and a body. But the idea of being both mind and body is neither innate nor known to be true with deductive certainty. Thus, the idea of the body must originate outside Descartes's mind: And . . . because I know that all things which I apprehend clearly and distinctly can be created by God as I apprehend them, it suffices that I am able to apprehend one thing apart from another clearly and distinctly in order to be certain that one is different from the other, since they may be made to exist in separation at least by the omnipotence of God. ... On the one side, I have a clear and distinct idea of myself inasmuch as I am only a thinking and unextended thing, and as, on the other, I possess a distinct idea of body, inasmuch as it is only an extended and unthinking thing, it is certain that this I [that is to say, my soul by which I am what I am], is entirely and absolutely distinct from my body and can exist without it. . . . But, since God is no deceiver, it is very manifest that He does not communicate to me these ideas immediately and by Himself. ... I do not see how He could be defended from the accusation of deceit if these ideas were produced by causes other than corporeal objects. Hence we must allow that corporeal things exist. Descartes reasoned that his own ideas of body and mind must be basically sound, since God allowed him to know clearly and distinctly that he is both. At this point, the Cartesian Genesis is essentially complete. All that remains are the details of reconstructing knowledge of the world on a solid base by carefully following the rules of method.

The Cartesian Fantasy

In a series of articles and essays collected in her influential book Unbearable Weight: Feminism, Western Culture, and the Body, Susan Bordo analyzes what she and other philosophers identify as hurtful, real-life consequences of what Bordo describes as "the Cartesian fantasy." Bordo is particularly interested in important, widespread, and, until recently, unrecognized, cultural limits and expectations that Cartesian dualism has exerted on gender and women's self-concepts. In the process, Bordo conducts an intriguing philosophical inquiry into the far-reaching effects that seemingly technical and academic philosophical arguments and doctrines can have on an entire culture. Bordo makes effective use of mundane examples from contemporary culture that include references to pop music, movies, commercials, and clothing to buttress her contention that we are all affected by Cartesian dualism. We don't have to be philosophers or even to have ever heard of Descartes or modernity to be dualists, at least some of the time. According to Bordo, modern dualism reinforces a culture-wide mechanistic, technologized view of the human body that has destructive consequences for the lives, aspirations, and self-concepts of women (and men and children). Dualism . . . cannot be deconstructed in culture the way it can be on paper. To be . . . culturally accomplished requires that we . . . legitimate and nurture . . . marginalized ways of knowing, speaking, being. — Susan Bordo The problem, as Bordo describes it, is a Cartesian fantasy built on the possibility of pure objectivity—a delusion that pure objectivity is attainable with sophisticated, rational, scientific effort. Herein lies our contemporary quest to observe and manage life from an idealized God's-eye perspective, or if reference to God offends us, from a pure, scientific, data-based perspective. We seek to transcend partiality, ethnocentrism, sexism, racism, particularity in short. We seek a "view from nowhere." Descartes, Bordo reminds us, believed that the mind could achieve the view from nowhere by adopting his rationalistic philosophical method. The careful, methodical Cartesian mind attempts to transcend the body and thereby escape the limited perspective of the material world. In this sense, the Cartesian mind philosophizes from nowhere. But, Bordo suggests, in addition to freeing philosophers to reason afresh, dualism also contributes to our culture's extraordinary goals of "defying aging, our various 'biological clocks,' and even death itself." When we think of our bodies as objects, as out there, we treat them as things to sculpt, trim, and maintain (like automobiles and healthy GPAs) according to cultural expectations and "objective" scientific standards of wellness and desirability. We observe and try to control, from a distance, as it were, our BMIs, our cholesterol levels, waistlines, wrinkles, crooked teeth, and biceps. We become rational ghosts inside of messy, embodied machines: Clearly, then, mind/body dualism is no mere philosophical position, to be defended or dispensed with by clever argument. Rather, it is a practical metaphysics that has been deployed and socially embedded in medicine, law, literary and artistic representations, the psychological construction of the self, interpersonal relationships, popular culture and advertisements, a metaphysics which will be deconstructed only through the concrete transformation of the institutions and practices that sustain it. . . . But it is not easy to "go beyond dualism" in this culture . . . If Bordo and other critics of depersonalization are generally correct (see Chapters 13-18), the scientific, technological, and cultural advances generated by modern science and philosophy carry a high price. This price includes widespread alienation from the natural world; fear and revulsion in the face of "messy" aspects of life such as birthing, caring, and dying; and the trivialization of the family in the name of "justice" and "objectivity."

Descartes's Ontological Argument

In the fifth Meditation, Descartes presents an argument for the existence of God based on the claim that it is impossible to conceive of or even imagine God without also thinking of existence. The very essence of the idea of God includes "all perfections," and certainly existence is a perfection. This line of reasoning is known as an ontological argument. The term ontology derives from the Greek roots onta, "truly real," and logos, "study of." An ontological argument is an attempt to prove the existence of God by referring either to the meaning of the word God when it is understood a certain way, or by referring to the purportedly unique quality of the concept of God. Descartes' Meditations probably rivals Plato's Republic as the work most frequently read or recommended as an introduction to philosophy. — Alexander Sesonske and Noel Fleming The purest form of the ontological argument first occurs in the Proslogion of St. Anselm (1033-1109). A Benedictine monk who eventually became the archbishop of Canterbury, Anselm attempted to provide a rational basis for Christian doctrine. He asserted that the very idea of God "contains existence" because by definition God is "that than which nothing greater can be conceived." And of any two things, a real one is "greater" than an imaginary one. Hence, an existing God is greater than a merely imaginary God. Therefore, by definition, the term God refers to a real, existing being. When we use God to refer to a fantasy being, we have changed its meaning. For Descartes, the idea of God (infinite perfection) is unique. It is an idea that can only be caused by something external to Descartes. More than that, it is an idea that must resemble the being that it is an idea of. That is not to say that our limited grasp of this privileged idea is adequate. Of course we cannot comprehend God. But we can, Descartes believes, clearly and distinctly grasp the uniqueness of the idea of God, and in so doing, we understand that existence is part of God's essence. He writes: This indeed is not at first manifest, since it would seem to present some appearance of being a sophism. For being accustomed in all other things to make a distinction between existence and essence, I easily persuade myself that the existence can be separated from the essence of God, and that we can thus conceive God as not actually existing. But, nevertheless, when I think of it with more attention, I clearly see that existence can no more be separated from the essence of God than can its having its three angles equal to two right angles be separated from the essence of a [rectilinear] triangle, or the idea of a mountain from the idea of a valley; and so there is not any less repugnance to our conceiving a God (that is, a Being supremely perfect) to whom existence is lacking (that is to say, to whom a certain perfection is lacking), than to conceive of a mountain which has no valley. But although I cannot really conceive of a God without existence any more than a mountain without a valley, still from the fact that I conceive of a mountain with a valley, it does not follow that there is such a mountain in the world; similarly although I conceive of God as possessing existence, it would seem that it does not follow that there is a God which exists; for my thought does not impose any necessity upon things, and just as I may imagine a winged horse, although no horse with wings exists, so I could perhaps attribute existence to God, although no God existed. But a sophism is concealed in this objection; for from the fact that I cannot conceive a mountain without a valley, it does not follow that there is any mountain or any valley in existence, but only that the mountain and the valley, whether they exist or do not exist, cannot in any way be separated one from the other. While from the fact that I cannot conceive God without existence, it follows that existence is inseparable from Him, and hence that He really exists; not that my thought can bring this to pass, or impose any necessity on things, but, on the contrary, because the necessity which lies in the thing itself, i.e. the necessity of the existence of God determines me to think in this way. For it is not within my power to think of God without existence (that is of a supremely perfect Being devoid of a supreme perfection) though it is in my power to imagine a horse either with wings or without wings.

Maybe It's All a Dream?

It seems to me that the greatest lesson of adult life is that one's own consciousness is not enough. — Sir Fred Hoyle Like most of us, prior to his investigations, Descartes had uncritically assumed that the most true and certain things known come from the senses. For example, it seems "obviously true" that my computer exists as I type this sentence, and it seems "obviously true" that the book you are reading exists. What could be more certain than simple, direct sensations and perceptions of our immediate environment? Ah, but our senses sometimes deceive us. For example, we may think we are looking at an airplane and later discover that it is a bird. Witnesses to crimes disagree over descriptions of perpetrators, and we sometimes think we recognize the figure coming down the sidewalk, only to be wrong. Even so, aren't we always sure of immediate sensations? Though our senses may deceive us about distant events, there are many other things we know through our senses "as to which we cannot reasonably have any doubt." Descartes reflects: At the same time I must remember that I am a man, and that consequently I am in the habit of sleeping, and in my dreams representing to myself the same things or sometimes even less probable things, than those who are insane do in their waking moments. How often has it happened to me that in the night I dreamt that I found myself in this particular place, that I was dressed and seated near the fire, whilst in reality I was lying undressed in bed! At this moment it does indeed seem to me that it is with eyes awake that I am looking at this paper; that this head which I move is not asleep, that it is deliberately and of set purpose that I extend my hand and perceive it; what happens in sleep does not appear so clear and distinct as does all this. But in thinking over this I remind myself that on many occasions I have in sleep been deceived by similar illusions, and in dwelling carefully on this reflection I see so manifestly that there are no certain indications by which we may clearly distinguish wakefulness from sleep that I am lost in astonishment. And my astonishment is such that it is almost capable of persuading me that I now dream. With this example, Descartes rejects sense knowledge as a sufficient foundation for certainty. In so doing, he also rejects the primacy of the external, physical world because it is possible that the whole so-called real world is nothing but an elaborate mental construct, a hallucination. Remember, in the interest of constructing a flawless philosophy, Descartes is being ultracautious. He will not settle for degrees of probability, no matter how "virtually certain" they may be. Whether or not you consider it probable that your world is a dream, Descartes points out that it is at least possible. But even if the world is a dream, it still has regularity and predictability, doesn't it? Maybe the world is just a dream implanted in the mind by God. Philosophical Query How do we know the difference between a dream or hallucination and reality? Seriously consider how a confused person might verify that he or she is or is not dreaming.

The Problem of Authority

Modern philosophy emphasizes methodology, technique, and personal, social, and historical detachment. Its origins lie in the decline of a stable social order, the loss of central authority by the Roman Catholic Church, and the proliferation of scientific advances. More sophisticated mathematics and improved scientific instruments had resulted in discoveries that challenged and contradicted Aristotelian naturalism. Scientists were able to move beyond metaphysical speculations to careful observations. No authority—religious or political—could refute what the individual observer saw or the individual mind calculated for itself. Descartes was a Catholic, but his argument that each individual possesses the "natural light of reason" and needs no intervening authority to interpret "the great book of the world" may remind you of Luther's claim that each person can go directly to God, without the church as an intermediary. In other words, Descartes, like Luther, set aside the so-called accumulated wisdom of the past, insisting that each person must examine what is true and false afresh. Descartes's scientific interests led him to observe and experiment for himself, and he soon discovered that Aristotle's authoritative writings on nature contained many errors: But so soon as I had achieved the entire course of study at the close of which one is usually received into the ranks of the learned, . . . I found myself embarrassed with so many doubts and errors that it seemed to me that the effort to instruct myself had no effect other than the increasing discovery of my own ignorance. And yet I was studying at one of the most celebrated schools in Europe. In Descartes's time, the distinction between science and philosophy was not clear. His interests and abilities in philosophy, mathematics, and science made this confusion especially intolerable to him. He expected scientific claims to be provable by appeals to observation and clear thinking. So he made a radical proposal: Let's start fresh, throwing out everything we think we know, and build a system of knowledge based entirely on ideas whose truth can be clearly and distinctly known—to us, firsthand.

Standard of Truth

No matter what method we employ in a search for truth, we must have some criterion for distinguishing truth from falsity. Descartes proposed that we "might assume as a general rule that the things which we conceive very clearly and distinctly are all true." He defined clear as "that which is present and apparent to an attentive mind" and distinct as "that which is so precise and different from all other objects that it contains within itself nothing but what is clear." We might say that for Descartes, knowledge requires precision and detail. Throughout his philosophical writings, Descartes appeals to clear and distinct knowing as the ultimate standard to be used in accepting or rejecting ideas. To produce the most certain conclusions possible, he rejected anything he did not know "clearly and distinctly." He also believed that certain very basic propositions need only to be understood to be recognized as true. To understand something clearly and distinctly, according to Descartes, is a matter of perceiving that there are no reasonable grounds on which it can be doubted. In other words, to recognize something clearly and distinctly is to know that it is true. Some philosophers are troubled by Descartes's standard of truth. They claim that the standard itself is ambiguous and subjective and thus cannot be known with clarity and distinctness. They accuse Descartes of basing his rationalism on the subjective states of the perceiver; they interpret this to mean that, in spite of his talk about reason, Descartes actually bases much of his philosophy on his feelings and moods. Their point is that "clear and distinct" vary from individual to individual; I might be convinced I know something clearly and distinctly and still be wrong about it. Philosophical Query A common criticism of Descartes's standard of truth is that he failed to apply it to itself. Do we know with clarity and distinctness that only what we know with clarity and distinctness is true? Can we know it? Not if, as critics claim, Descartes's standard is itself unclear and ambiguous. Do you have a clear and distinct idea of Descartes's criterion? How can we tell when an inability to perceive something clearly and distinctly is the fault of the individual or of the quality of the idea?

The Evil Genius

Perhaps, like Descartes, you are having some trouble seriously doubting your experiences of the real world. Descartes says, "These ancient and commonly held opinions [that I am not dreaming] still revert frequently to my mind." To better test his most persistent beliefs, Descartes decides to allow himself deliberately "to be deceived, and for a certain time pretend that all these opinions are entirely false and imaginary." Descartes is in no danger of losing his bearings; this is still methodic doubt, not real confusion or delusion. He even says not to worry about giving in to too much doubt and distrust, since he is "not considering the question of action, but only of knowledge." At this point, Descartes introduces one of the most intriguing figures in the history of philosophy, the evil genius: I shall then suppose, not that God who is supremely good and the fountain of truth, but some evil genius not less powerful than deceitful, has employed his whole energies in deceiving me; I shall consider that the heavens, the earth, colours, figures, sound, and all other external things are nought but the illusions and dreams of which this genius has availed himself in order to lay traps for my credulity; I shall consider myself as having no hands, no eyes, no flesh, no blood, nor any senses, yet falsely believing myself to possess all these things; I shall remain obstinately attached to this idea, and if by this means it is not in my power to arrive at the knowledge of any truth, I may at least do what is in my power [i.e., suspend my judgment], and with firm purpose avoid giving credence to any false thing, or being imposed upon by this arch deceiver, however powerful and deceptive he may be. This cold possibility of ultimate delusion concludes the first Meditation. Descartes has reduced his world to himself and one all-powerful, all-evil source of deception. He reasons that if he can find one anchor point of undoubtable certainty in the midst of the possibility of error in all quarters of his life, he will have found his unshakable foundation. Philosophical Query Before reading any further, stop for a moment and play with Descartes's idea of an evil genius. Try to get into the spirit of doubting as much as you can. Do not be limited by what you actually doubt; this is an intellectual exercise, not a personal confession. See if you can extend the range of what might on the remotest possibility be false or other than what you think it is. Can you be absolutely sure that there is no evil genius?

Rationalism

Rationalism is an epistemological position in which reason is said to be the primary source of all knowledge, superior to sense evidence. Rationalists argue that only reason can distinguish reality from illusion and give meaning to experience. In general, rationalists believe that abstract reasoning can produce undeniable, absolutely certain truths about nature, existence, and the whole of reality. Many of these ultimate truths can be discovered without observation, experiment, or even experience. These are called a priori ideas or, sometimes, innate ideas. Thus, to the rationalists, reason—not empirical observation—is the ultimate test of truth. Queen Christina of Sweden watches a demonstration by Descartes (standing at right). Stock Montage/Getty Images According to the coherence theory of truth, new or unclear ideas are evaluated in terms of rational or logical consistency and in relation to already established truths. The ultimate criteria for basic, originating truths are clarity and distinctness. Once fundamental truths are established, the rationalist uses a deductive, mathematical/logical method to test and establish other, more complex ideas. True ideas are coherent (rationally consistent) with each other, and the rationalist's aim is to achieve absolute certainty of the sort possible in mathematics. "My method," said Descartes, "contains everything which gives certainty to the rules of arithmetic." The coherence theory of truth is in direct opposition to the correspondence theory of truth (Chapter 10) and differs from the other major theory of truth, the pragmatic theory of meaning (Chapter 15).

René Descartes: The Solitary Intellect

René Descartes (1596-1650) was born into an old and respected family in the French province of Touraine. His mother died of tuberculosis a year after his birth, and Descartes believed he inherited a frail constitution from her. His father was a famous lawyer, whose career kept him away from home for months at a time. When he was approximately nine years old, Descartes was sent to the Jesuit college at La Flèche, where his physical weakness and mental strength were both acknowledged, and he was allowed to sleep later than the other students (a lifelong habit). At La Flèche, Descartes studied Greek, Latin, history, liberal arts, science, mathematics, and philosophy, in addition to music, dancing, and fencing. René Descartes After completing his studies at La Flèche, Descartes spent the next few years living the life of the young gentleman he was. He practiced fencing, rode horses, and—already in love with mathematics—briefly took up gambling to see if he could devise a system to break the bank. At the University of Poitiers, he earned degrees in civil and canon law. As soon as age permitted me to emerge from the control of my tutors, I quitted the study of letters . . . resolving to seek no other science than that which could be found in myself, or at least in the great book of the world. — René Descartes In 1618, when Descartes was twenty-two years old, the Thirty Years' War broke out. To the surprise of his friends, a strong, healthy Descartes enlisted in the army of the Prince of Nassau and later joined the army of the Duke of Bavaria. It is not clear whether he ever saw combat. On November 10, 1619, Descartes had a revelation that transformed him and ultimately changed the direction of Western philosophy. As he later wrote, "I remained the whole day shut up alone in a stove-heated room, where I had complete leisure to occupy my thoughts." There, Descartes says, he "discovered the foundations of a wonderful new science." The next night, full of excitement and anticipation over his discovery, he had three dreams, in one of which he heard a clap of thunder. He took it to be "the Spirit of Truth descending to take possession" of him. Descartes believed he had been divinely encouraged to establish a universal method of reasoning, based on mathematical principles, which, if followed carefully enough, would guarantee the absolutely certain truth of its results. After this remarkable experience, Descartes's outward life seemed little changed. His inheritance, first from his mother and then from his father, had freed him from the need to make a living, so he traveled, studied, conversed, and wrote. He lived alone most of his life, except for his servants, and during a twenty-year period lived in twenty different houses. Solitary and secretive, Descartes preferred to avoid the distractions and commotion of city life and social involvements. Most of his philosophical discourse took the form of letters. There were times when he didn't want his friends to know where he was; he even asked them not to write to him for a while. Descartes thought he worked better this way, completely free to devote all his energy, at his own pace, to his studies. In a letter to a friend, Descartes wrote from Amsterdam: "And thus in this large city where I now am, since I seem to be practically the only one here who is not a merchant or in trade; all are so bound up in their profitable business transactions that I could remain here my entire life without being noticed by anyone." Living this way, Descartes was able to study philosophy, geometry, physics, optics, circulation, and other subjects. Conducting experiments and dissections, as well as making important discoveries in mathematics, he rejected the Scholastic model of science and philosophy, turning instead to firsthand observations and deductions. Descartes' metaphysics, as he so clearly sees himself, is the natural product of a precious ingredient of the past which today is in danger of rapid extinction—privacy—that marvelous compound of withdrawal, self-reliance, quiet, solitude, contemplation, and concentration which seems the exclusive possession of a bygone age. — A. W. Levi In 1635, Descartes had an illegitimate daughter (who died at the age of five) with a servant girl. Later, he referred to the episode as "a dangerous commitment" from which he had "extricated" himself. He was not entirely immune to the charms of women, however. He had a close six-year correspondence with Princess Elizabeth, daughter of the dethroned queen of Bohemia. When she was nineteen, the princess read his Discourse on Method and was surprised and delighted to discover philosophy written in clear, everyday language. Through a friend who had become the French ambassador to the court of Queen Christina of Sweden, Descartes was ultimately convinced in September 1649—against his better judgment—to join her court in Stockholm. He was not happy there. He had little time for his experiments, and the queen forced him to break his lifelong habits of sleeping late and working at leisure—she wanted to be tutored in philosophy at five in the morning! This forceful woman even managed to get Descartes to write a ballet. The cold weather and austere conditions weakened his already frail health. By the end of January 1650, he was ill with pneumonia. He died February 11, two months before his fifty-fourth birthday. René Descartes stands not only as the father of modern philosophy but also as the original archetype of the modern rationalist: He boldly relied on the disciplined use of his own reason; he refused to accept as true anything that did not square with what he had personally verified as true; he exalted the thinking, conscious self as the foundation of all certainty.