Meditations on First Philosophy (with Objections and Replies) | Study Guide

René Descartes

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Meditations on First Philosophy (with Objections and Replies) | Summary



Letter of Dedication

Descartes appeals to the faculty at the Sorbonne, a prestigious university in Paris, to offer comments on his work. He declares his aim is to provide philosophical proof of God and the immortality of the soul.

Preface to the Reader

Descartes explains the relation between his previous work, Discourse on Method, and the current Meditations. He also addresses two criticisms of Discourse. The first involves the nature of the mind, and the second involves "stock" arguments from atheists.


First Meditation

The Meditator, or thinker, sets out to eradicate all false beliefs in order to establish a certain foundation for knowledge in the sciences. He finds most of his beliefs are directly or indirectly derived from sense perception, so he decides his senses are not to be trusted. To this he objects, however, that immediate sensations—such as those he experiences while "sitting by the fire in his gown"—seem indubitable. He realizes they are doubtful, however, when he considers that insane people hallucinate.

Then he realizes he does not even need to be insane in order to doubt sense experience. After all, he often has vivid dreams. Indeed, if sensation is the standard he cannot determine whether or not he is dreaming right now.

Rather than settle this question, the Meditator decides to assume he is dreaming. Within this state, he can pursue whether or not anything can be known with certainty. After analyzing the general contents of his dreams, he concludes that they exhibit mathematical features, which are certain, and claims "For whether I am waking or sleeping, two plus three equals five."

This supposed certainty is called into doubt, however, when he realizes he may be deceived into thinking this way. It could be that, on a whim, the deceiver makes him believe something different with certainty. This deceiver may be God. However, not only does the Meditator not know if God exists, but if he does exist, he would not likely be a deceiver. Therefore, the Meditator supposes an evil genius is deceiving him.

Second Meditation

The Meditator decides to intensify the sense of doubt. He will assume all his beliefs are false, not only those derived from sense experience. What follows from this is that the entire world, and his own body, are deemed illusions. It may be that "some God" makes him think as he does, or perhaps he is the source of his own thoughts. If he is the author of his own thoughts, then it follows he exists, but it is not clear how. After all, he has denied he has a body. He could, however, exist without a body. Therefore, since he just convinced himself of something—namely that he doesn't exist—then, even without a body, he exists. This is not certain, however, since it is possible a deceiver (and evil genius) is purposefully and continuously deceiving him. Here, however, he finds certainty: if he is deceived, he must exist.

The certainty of his existence as a thinking thing is the only knowledge the Meditator has, and he wants to know more about what sort of thing a thinker is. Eventually, however, he returns to an uncertain—but still compelling—belief: bodies exist. He decides to examine a piece of wax to see what he can learn from it but instead learns more about himself as a thinking thing. More specifically, he realizes that when he thinks about objects of sensation, it is his judgment about them—an act of the mind—rather than sensation itself that can be erroneous.

Third Meditation

The Meditator turns his attention to whether or not God exists. Resolving this question is crucial to gaining further knowledge. After all, he may still be deceived. Moreover, apart from the certainty that he exists, the Meditator does not know if he will make erroneous judgments either because of the aforementioned deception or due to some personal defect. He is armed with a general rule gleaned from the certainty "I think." Thus, clearly and distinctly perceived ideas are true.

The Meditator reasons from his ideas that God exists. One idea is of a supremely perfect being. The cause of this idea has to be at least as real as the idea itself. Since the Meditator is not perfect, he could not be the cause of it. He concludes, therefore, that God exists.

Fourth Meditation

Armed with proof of God's existence, the Meditator turns to the question of how he can make errors. The problem is, if God created and sustains him, then he could surely have avoided giving the Meditator a faculty for making mistakes; namely, the faculty of judgment. After considering some reasons why he is flummoxed, the Meditator arrives at a reason for his errors: his will—which chooses to affirm or deny ideas—often extends beyond the restrictions of the clear and distinct ideas presented. The will could suspend judgment about an opaque idea, but when it does not it is liable to make an incorrect choice. Consequently, God is not responsible for making the Meditator err, or even for giving him a faulty faculty. Instead God has given him free will.

Fifth Meditation

The Meditator returns to the question of whether or not bodies exist. He has some certain knowledge and multiple ideas that suggest an external world, but he has yet to bridge the gap between mind and the possible world. Mathematics suggests a way forward. If there are bodies, their essence is extension. The Meditator thinks, in establishing the essence of material things, he has established at least the plausibility of their reality.

An examination of the concept of God also reveals the divine essence: perfection. Moreover, since necessary existence is a perfection, it follows that God necessarily exists. Existence is effectively built into the concept of God and is inextricable from it.

Sixth Meditation

The Meditator has arrived at the point when he can make convincing arguments about the existence of bodies and the relation between his mind and his body. He argues from the function of his imagination to the conclusion that material things exist. He then argues that the essential differences between mental and material substances entail a distinction between mind and body. Finally, he is able to resolve his doubt about dreaming by arguing for the distinction between dreaming and waking states.

Objections and Replies

There are seven sets of objections and replies. Each set contains multiple criticisms and Descartes's replies. The thrust of the objections and replies is that they allow the reader to observe Descartes interacting with criticisms of his work and clarifying or further articulating his positions. The main themes the objectors addressed are:

  • Clear and Distinct Ideas and Knowledge
  • The Cogito ("I think")
  • Ontological Argument for the Existence of God
  • Mind/Body Distinction
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