Meditations on First Philosophy

by René Descartes

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In Meditations on the First Philosophy, René Descartes delves into epistemology, or the theory of knowledge. He asks questions such as whether there is such a thing as knowledge, and if so, what distinguishes it from opinion. However, in order to answer these questions and to validate knowledge, it was necessary to raise the fundamental questions of being.

Descartes chooses to present his thoughts as meditations; he represents himself as seated before a fire in a cozy Dutch dwelling, wrapped in his dressing gown, freed from worldly care, and ready to devote himself to a task to which he had for some time looked forward, a kind of mental housecleaning. On six successive days, he pursues his meditation, step by step, clearing his mind of all error.

In Discours de la méthode (1637; Discourse on Method, 1649), Descartes reveals that the work was actually composed in very similar circumstances. In 1628, Descartes was in his thirties and living in Holland; he had withdrawn from a more active life for the special purpose of carrying on his philosophical and scientific investigations. Meditations on First Philosophy was circulated in manuscript, and when it was published in 1641, it included a lengthy appendix composed of objections by leading philosophers—including Thomas Hobbes and Pierre Gassendi—together with Descartes’s replies.

The First Meditation

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The First Meditation is, in a way, distinct from the rest. It describes Descartes’s effort, which in fact engaged him for many years, to accustom himself not to think of the world in the imagery of the senses or according to the notions of common sense and the traditions of various schools of thought.

Can it be, Descartes wonders, that all beliefs that he had formerly held are false? Perhaps not, but if he is to achieve his goal of building up a body of incontrovertible truth, he must exercise the same rigor toward beliefs that are merely uncertain as toward those that are demonstrably untrue. That is to say, he must make doubt his tool. Instead of allowing it to hang over him, forever threatening, he must grasp it firmly and lay about until he has expunged from his mind every pretended certainty.

The first to go are those beliefs that depend on the senses—notably one’s belief in the existence of one’s own body and of everything that appears to the sight and touch. One’s habitual judgment protests. What can be more certain, Descartes asks himself, than that I am seated by the fire holding this paper in my hand? However, he writes, when one reflects that one’s dreams are sometimes attended with equal confidence, one is forced to conclude that there is no infallible mark by which one can know true perceptions from false.

Of course, what one doubts is, in this case, only that one’s ideas represent something beyond themselves. Descartes is one of the first philosophers to use the word “idea” in the modern sense. He means by it “whatever the mind directly perceives.” However, he distinguishes between the idea taken only as a mode of thought and the idea as a representation of reality. Even in dreams, one cannot deny the former. What one challenges is the “truth” of the ideas—Descartes calls it “objective reality”—and of judgments based on them. His question is whether there is anything in sense-images that testifies unmistakably to the truth of what they represent. Obviously not in those that one initiates in dreams and fantasies, and no more, he argues, in those that come from without, through the senses, or else how could one make mistakes as to sounds and sights?

There is, he says, another...

(This entire section contains 714 words.)

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class of ideas that one seems neither to originate nor to receive from without but to be born with—those, for example, that make up the science of mathematics. Two plus three equals five, even in dreams, for this sum does not require material counters to make it true. Yet, the ideas of numbers profess to be something besides modes of thought. They do have “objective reality.” However, people have been mistaken about mathematical matters, so they are no more self-authenticating than sense-images. People’s habitual trust in them resembles that which they place in their senses and has the same foundation, namely, that people are creatures of a benevolent deity who would not deceive them. Suppose that this is not the case, and that mathematics is merely a fancy of one’s mind. Or, worse, suppose it is an illusion deliberately imposed upon people by a malicious demon who has access to the workings of their minds. This is not unthinkable.

Instead of supposing that the providence of God sustains his thinking, Descartes resolves to hold fast to the hypothesis that he is constantly being deceived by an evil spirit, so that all his ordinary beliefs are false. In this manner, while he seems to make no progress in the knowledge of truth, he at least habituates himself to suspend judgment concerning things that he does not certainly know. However, this is not easy. Descartes pleads with his readers (in the replies to his objectors) not merely to give the exercise such time as is required for reading the meditation through but to take “months, or at least weeks” before going on further. He suggests how reluctant one is to break old habits of thinking by describing a slave who, when sleeping, dreads the day and conspires to weave the sounds of gathering dawn into his dreams rather than to embrace the light and labors that it brings.

The Second Meditation

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Descartes’s aim in the Second Meditation is to discover, if possible, some foundation of certainty that doubt is powerless to assault. He has doubted the reality of the world presented to him through his senses. Shall he affirm that some god (or devil) must exist to put these ideas into his mind? That hardly seems necessary, for perhaps he has produced them himself. One thing, however, seems now to loom up in Descartes’s mind: “I myself, am I not something?” Suppose all his ideas are hallucinations, whether self-induced or planted in him by some god or devil. In this, at least, he cannot be deceived: “I am, I exist, is necessarily true each time that I pronounce it, or that I mentally conceive it.”

Here, then, for the first time, Descartes presents a self-validating judgment. It is the unique instance in which people immediately encounter the existence that is represented to them by an idea: One has an idea of “oneself.” Like other ideas, this one claims to have objective reality. However, unlike other ideas, this one’s claim is open to inspection—by the self. Both the idea and the existence that it represents are present each time one thinks them. In a simple act of “mental vision” (to use Descartes’s expression), one knows that one exists. As the philosopher John Locke would say, one knows one’s own existence intuitively.

With this certitude to serve as a cornerstone, Descartes proceeds to raise his palace of Truth. If one explores the structure of one’s inner consciousness, one will find the clue to universal Being. For instance, one can ask the question “What am I?” The answer lies at hand: “I am a thing that thinks.” For was it not in the act of thinking (taken broadly to include all conscious activities) that one found the reality of the idea of oneself? Contrast this with the traditional view that a person is a body that contains a subtle essence, a very fine grade of matter, known as spirit: There is nothing certain, or even intelligible, about this idea. If one presses ahead with methodical doubt, one discovers that most of the ideas habitually associated with matter are illusory. Take a piece of wax fresh from the honeycomb: One thinks of it in terms of color, taste, odor, and texture. However, none of these is essential to the wax. Place it near the fire, and all the qualities that engross the imagination are altered. All that remains unchanged and can be called essential to the wax is “something extended, flexible, movable,” properties that are knowable to the intellect and not to the senses. In any case, whether one has a body, it is not as body that one knows the self when one beholds the self as existing. The realm of being that one discovers there has nothing about it of extension, plasticity, or mobility. One is a thinking being, Descartes concludes, a mind, a soul, an understanding, a reason.

The forward progress during the second day’s meditation was all made along the path of doubt. It was the act of doubting that gave Descartes the certainty both that he existed and that his nature was mind. However, the implications of his consciousness of doubt have not been exhausted. Does not doubt carry with it, and actually presuppose, the idea of certainty, just as error carries with it the idea of truth? Descartes finds in his mind the idea of a perfect being by comparison with which he is aware of his imperfections, a self-sufficient being by which he knows that he is dependent. Following this lead, he proceeds in his Third Meditation to demonstrate the existence of God.

The Third Meditation

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Descartes’s argument takes two forms. First, he asks directly concerning the idea of a perfect being, whence it could have come into his mind: From some other creature? From himself? Or must there exist a perfect being to originate the idea? His answer is obscured for the modern reader by the late-medieval philosophical framework in which it is expressed. The idea of God contains more “objective reality” than any other idea (including one’s idea of self). However, a more perfect idea cannot be generated by a less perfect being. Therefore, the idea of God in his mind must have been placed there by God himself.

The second form of the argument proceeds from the contingent quality of his own existence, made up as it is of fleeting instants, not one of which is able either to conserve itself or to engender its successor. Much in the argument is reminiscent of the traditional Aristotelian proof; but there is this difference, which makes it clear that the new argument is only another version of the first: What needs explanation is not merely the existence of a contingent being or of a thinking being but of “a being which thinks and which has some idea of God.” Thus, the principle that there must be at least as much reality in the cause as in the effect precludes the possibility that any being less perfect than God could have created Descartes—or any person.

This argument is of scarcely more than historical interest. The same is true of the argument from the Fifth Meditation that, since existence is a perfection, the idea of a Perfect Being entails the existence of that Being. However, it must be pointed out that behind the framework of traditional theistic proof lies a claim that rationalistic philosophers have found valid even in modern times:I see that in some way I have in me the notion of the infinite earlier than the finite—to wit, the notion of God before that of myself. For how would it be possible that I should know that I doubt and desire, that is to say, that something is lacking to me, and that I am not quite perfect, 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?

Here, in effect, is a new kind of reasoning. The Scholastics were committed to demonstrate the existence of God by syllogisms, and whether through expediency or inadvertency, Descartes makes a show of doing the same. However, in Descartes a new, quasi-mathematical way of reasoning was pushing the syllogism to one side. His true ground for affirming the existence of God was not that it follows from but that it is implicit in his consciousness of himself.

Blaise Pascal’s famous memorial that insists that the God of the philosophers is not the God of faith is a useful reminder to the general reader. There is no need, however, to suppose that Descartes needed it. The certainty of God’s existence is a great triumph—but for scientific, rather than for religious, reasons. It is the sine qua non of all further knowledge, since “the certainty of all other things depends on it so absolutely that without this knowledge it is impossible ever to know anything perfectly.” Such obvious mathematical truths as two plus three equals five are not self-validating because they bear no evidence of the competency of one’s thought. In replying to his objectors, Descartes says atheists cannot be sure, hence their knowledge cannot be called science. Doubt may never rise to trouble him; but if it does, he has no way of removing it. However, the doubt is removed when a person recognizes that his mind owes its constitution and working to the creativity of God, and that God is no deceiver.

Knowledge of the World

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Much of the rest of Meditations on First Philosophy is devoted to determining just how far people can trust the faculties that the beneficent Deity has implanted in them. First, one must distinguish between impulses that incline one to belief (such as “the heat that I feel is produced by the fire”) and insights into necessary truths (such as “a cause must be as great or greater than its effect”). Both are natural, and owing to the good offices of the Creator. However, the former can be doubted, even after one has discovered the truth about God; the latter, which Descartes speaks of as “the light of nature,” cannot be doubted at all. They are the principles of reason in our minds by which we arrive at knowledge. One has no other means of distinguishing between true and false.

Second, one must consider the causes of error. It is axiomatic that God can never deceive people and that if they make proper use of the abilities received from the Deity, they can never go wrong. Yet obviously, God has chosen to make people fallible. This situation arises from the fact that the intellect is finite, together with the fact that the will is infinite. One can see why both these things must be and how, as a consequence, people do not easily stay within the narrow realm of truth. The crux of the matter is that, for Descartes, judgment involves the will (in the form of “assent” or “dissent”). It is within people’s power to withhold judgment when convincing evidence is wanting and to give it only when the light of reason demands. Indeed, Descartes held that people have a duty to bring judgment under this rule. Failure to do so involves not merely error but sin.

Third, one’s knowledge of the external world creates a number of problems. Descartes examined a piece of wax to find what constitutes the essence of matter. He observed that the sensible qualities that people most readily believe to be in matter are not part of the nature of wax, as are such attributes as extension, figure, and mobility, which are not properly sensible but intelligible. Comparing the two ways of thinking about things in nature, Descartes concludes (following the lead of Galileo) that the senses provide people only the most confused notions of matter—they arise from the influence upon the mind of the body to which it is united rather than from the mind’s apprehension by its own light of the necessary attributes of being. It is by the latter that people obtain true knowledge of nature, which henceforth is seen to possess only those qualities that can be described in mathematical terms. In other words, the physical world has to be envisaged as a vast, complicated machine—but not the way the senses view machines, rather the way they are viewed on the drawing board and in the mind of the engineer.

So far reason leads people, Descartes says. If there is a material world, its nature must be as classic mechanics conceives it. However, it does not follow that a material world actually exists. It is conceivable that each time one receives and recognizes the idea of a body, God himself impresses it on one’s mind. Nothing in the idea of matter is inconsistent with its nonexistence. All that one can discover that inclines one to assent to its existence is an instinctive impulse such as attaches to all one’s sense perceptions; this, of course, is no reason.

Descartes’s only recourse is to appeal to the good faith of God. Thus, he writes that if God were the cause of our ideas of matter, he would undoubtedly have given us the means of knowing that this is the case, for he is no deceiver. In granting us free will, he has, indeed, opened the door to falsity and error, but he has not permitted any error without placing within one’s reach the means of avoiding it, or, at least, correcting it once it has been made. The claims of one’s sense-images, which reason disproves, is an example. However, no analysis disproves the natural inclination that one has to believe that corporeal objects do exist. Hence, one is justified in affirming, along with the existence of finite mind (one’s own) and infinite Being, the actuality of the material world. (Apparently, for Descartes, the existence of other minds is never more than an inference.)

The upshot of Meditations on First Philosophy is, then, to replace the commonsense picture of nature with one that is amenable to rational investigation. The new cosmology that was being shaped by scientists and thinkers such as Johannes Kepler, Galileo, William Gilbert, and others rested upon fundamental assumptions that were not clear to the investigators themselves. It was the task of Descartes to give these principles their classic formulation.


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Additional Reading

Chappell, Vere, ed. Descartes’s Meditations: Critical Essays. Lanham, Md.: Rowman and Littlefield, 1997. A significant collection of essays by scholars who carefully assess the perspectives and problems in one of Western philosophy’s most important texts.

Copleston, Frederick. A History of Philosophy: Modern Philosophy. Garden City, N.Y.: Doubleday, 1964. Copleston situates René Descartes in the history of philosophy with an accessible discussion of Descartes’s major theories.

Cottingham, John, ed. The Cambridge Companion to Descartes. New York: Cambridge University Press, 1992. A helpful collection of essays focusing on a variety of topics in Descartes’s thought.

Cottingham, John. Descartes. New York: Basil Blackwell, 1986. Taking a broad view of Descartes’s philosophy, Cottingham focuses on Descartes’s views about human nature as well as on his theory of knowledge.

Cottingham, John. Descartes. New York: Routledge, 1999. An excellent biographical introduction to the thoughts of the philosopher, clearly presented and requiring no special background. Bibliography.

Foley, Richard. Working Without a Net: A Study of Egocentric Epistemology. New York: Oxford University Press, 1993. A careful exposition of Descartes’s analysis of skepticism and the prospects human beings have for obtaining knowledge.

Gaukroger, Stephen. Descartes: An Intellectual Biography. New York: Oxford University Press, 1995. A veteran interpreter of Descartes offers an important account of Descartes’s intellectual development and the times and places in which it took place.

Jones, W. T. A History of Western Philosophy: Hobbes to Hume. New York: Harcourt, Brace and World, 1969. Offers a clear and accessible introduction to Descartes’s philosophy.

Keeling, S. V. Descartes. New York: Oxford University Press, 1968. This analysis of the merits and defects of Descartes’s philosophy provides a good overview of his thought and influence.

Kenny, Anthony. Descartes: A Study of His Philosophy. New York: Random House, 1968. A standard commentary for beginning students of Descartes’s philosophy, which gives particular emphasis to his theory of knowledge.

Rorty, Amélie Oksenberg, ed. Essays on Descartes’ “Meditations.” Berkeley: University of California Press, 1986. Prominent philosophers, representing different perspectives, offer well-crafted studies of Descartes’s best-known work.

Schouls, Peter A. Descartes and the Possiblitiy of Science. Ithica, N.Y.: Cornell University Press, 2000. An examination of the role of imagination in Cartesian philosophy.

Sepper, Dennis. Descartes’s Imagination: Proportion, Images, and the Activity of Thinking. Berkeley: University of California Press, 1996. Explores Descartes’s views about the nature of human experience and its prospects for obtaining knowledge about reality.

Strathern, Paul. Descartes in Ninety Minutes. Chicago: Ivan Dee, 1996. A quick but helpful introductory overview to key points in Descartes’s thought.

Vinci, Thomas C. Cartesian Truth. New York: Oxford University Press, 1998. An evaluation of the strengths, weaknesses, and implications of Cartesian approaches to questions about knowledge and truth.

Williams, Bernard. Descartes: The Project of Pure Enquiry. Harmondsworth, England: Penguin Books, 1978. A detailed, analytic dissection of the careful structure of Descartes’s most important philosophical arguments.

Yolton, John W. Perception and Reality: A History from Descartes to Kant. Ithaca, N.Y.: Cornell University Press, 1996. Yolton appraises the significance of Descartes’s attempts to show how it is possible for human beings to obtain knowledge in spite of skepticism.