Meditations on First Philosophy

First Meditation

What can be called into doubt

Descartes leads us into the minimal state of mind that is the basis of the Meditations, a total skepticism:

I realized that it was necessary, once in the course of my life, to demolish everything completely and start again from the foundations if I wanted to establish anything at all in the sciences that was stable and likely to last.

This is an exercise in thought since, as he states in the synopsis, “no sane person has ever seriously doubted” the existence of things outside of oneself. His goal, then is to compare the relative uncertainty of something like sense experience to the much stronger case, on his view, for the existence of God and the mind (separate from the body).

The state of dreaming gives us reason to doubt our experiences, since the dreamer often thinks he is seeing or feeling something real. But “the visions which come in sleep are like paintings, which must have been fashioned in the likeness of things that are real.” This hints at the later argument (Med. III) that ideas (like that of God) must come from something that contains their reality.

It is the senses rather than the intellect that we doubt. Take the refraction of a stick underwater. Our sight tells us that it is bent, while our touch tells us it is not. Our touch corrects our sight, but “the sense alone does not suffice to correct the visual error: in addition we need to have some degree of reason which tells us” which judgement to believe. [Sixth Replies]

Here we also get the notion that, while sense experience must be doubted, abstract truths are not so effected by our irrationality: “For whether I am awake or asleep, two and three added together are five, and a square has no more than four sides.” Such statements could only be false if they had been planted by a deceitful God.

Second Meditation

The nature of the human mind, and how it is better known that the body

The cogito, ergo sum argument is laid out here (though the exact phrase is never used): “this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.” This is derived not from a syllogism, but recognized as “something self-evident by a simple intuition of the mind.” [Second Replies] If it required previous knowledge “acquired by means of demonstrations,” there would be an infinite regress. Rather, “it is quite suffiencent that we should know it by that internal awareness which always precedes reflective knowledge,” so inate that we cannot fail to have it. [Sixth Replies]

And since thinking is connected as such to existence, and sense experience is to be doubted, thinking and existence are said to be equivalent, i.e., man is a thinking thing:

. . . thought; this alone is inseparable from me. I am, I exist — that is certain. But for how long? For as long as I am thinking. For it could be that were I totally to cease from thinking, I should totally cease to exist.

Third Meditation

The existence of God

Certainty that we are thinking things was established by its being perceived “very clearly and distinctly” as true — Descartes posits this test stands for being certain about anything. But since it is possible that there is a deceiving God (a “slight doubt” to be removed), one still cannot be sure about the existence of anything outside himself. Thus he examines here “whether there is a God, and, if there is, whether he can be a deceiver.”

Descartes seeks the source of his understanding of what anything is; he notes that it “seems to derive simply from [his] own nature,” though some ideas are thought to come from outside oneself, independent of will, since “I feel the heat whether I want to or not.” This is one simple reason why one believes in an outside-of-oneself; the other is that “Nature has apparently taught [us] to think this.” The natural impulse has proven unreliable, and thus that argument is dismissed. On the question of things external to will, “it does not follow that they must come from things located outside me,” as there could exist unwilled internal forces (like dreaming) that produce such ideas.

Important in the rest of the Meditation are the Scholastic definitions of objective and formal reality, which Descartes uses without explanation — common knowledge among his contemporaries. Objective reality is contained in ideas (objects of the mind), while formal reality is actual. Mental objects represent forms. Reality is hierarchical in that some things contain more reality than others. Modes and accidents describe features of substances, so they rely on the existence of substance, and contain in themselves less formal reality.

The idea of God is that of an infinite substance, and so has more objective reality than the ideas representing finite substances. But “there must be at least as much [reality] in the efficient and total cause as in the effect of that cause,” since a cause cannot give to the effect something it does not have. Thus, “for a given idea . . . it must derive [objective reality] from some cause which contains at least as much formal reality as there is objective reality in the idea.” The jump from objective to formal is made by the following argument: If some objective reality was derived from other objective realities, and so on, there would be an infinite regress, and objects would never have a formal basis. So “eventually one must reach a primary idea, the cause of which will be like an archetype which contains formally all the reality which is present only objectively in the idea.”

The idea of substance may be innate, since we are substance. But the idea of an infinite substance is not, so must have a cause, and the initial cause must have “proceeded from some substance which really was infinite,” that is, God.

As for God’s existence as a singular being, rather than multiple partial causes, Descartes says “no cause could have made me understand the interconnection and inseparability of the perfections without at the same time making me recognize what they were.” Since unity is one of the important, perfect aspects in his idea of God, and a collection of partial causes could not contain formal unity, God must be singular.

Finally, God “cannot be a deceiver, since it is manifest by the natural light that all fraud and deception depend on some defect.”

Fourth Meditation

Truth and falsity

The more skilled the craftsmen the more perfect the work produced by him; if this is so, how can anything produced by the supreme creator of all things not be complete and perfect in all respects?

One simple out frequently taken by believers is stated again here: our knowledge is limited; we cannot know better than God why he has made certain choices of our creation. And since we have established that God exists and is without defect, it is quite possible that what we see as our defects is actually necessary for his perfect creation, but in a way beyond our understanding. A possible explanation for our apparent faults is the existence of the universe as a perfect whole, whose parts do not necessarily need to contain all of the perfections in themselves, but instead perform their own functions.

Choices seem to depend on two forces, the will and the intellect. Freedom of choice is identified with both the ability to do or not do X, and with having complete information on which to make a choice:

For in order to be free, there is no need for me to be capable of going in each of two directions; on the contrary, the more I incline in one direction — either because I clearly understand that reasons of truth and goodness point that way, or because of a divinely produced disposition of my inmost thoughts — the freer is my choice.

Descartes finds the reason for human mistakes in judgement in the gap between the capacities of will and intellect. The will is “so great that the idea of any greater faculty is beyond my grasp” — there is little evidence for varying degrees of will. One either has the freedom to do or not do X or he does not, though God has an infinitely broader range of choices. The intellect is more limited; if one used his will only in cases where his intellect could fully understand the relevant variables, he would not be mistaken. This is the source of error: “instead of restricting it within the same limits, I extend its use to matters which I do not understand.”

Fifth Meditation

The essence of material things, and the existence of God considered a second time

Non-material objects, concepts, and their properties are something, rather than nothing, since the meditator is clearly aware of them, and it was previously established that whatever is perceived clearly and distinctly was true, and therefore something:

When, for example, I imagine a triangle, even if perhaps no such figure exists, or has ever existed, anywhere outside my thought, there is still a determinate nature, or essence, or form of the triangle which is immutable and eternal, and not invented by me or dependent on my mind.

The idea of God is thought to be of a similar nature; it is found within oneself “just as surely as the idea of any shape or number.” And this idea of God has the property of (eternal, infinite, or perfect) existence. Since God has all of the perfect attributes attributed to him, one finds it impossible to conceptualize this notion of God without any particular perfection, including existence. So “existence is inseparable from God,” and he must exist.

Continuing the discussion of truth, which is reliant on the existence of a non-deceiving God, we find that a basin of true knowledge can be collected in the following way:

. . . even if I am no longer attending to the arguments which led me to judge that this is true, as long as I remember that I clearly and distinctly perceived it, there are no counter-arguments which can be adduced to make me doubt it, but on the contrary I have true and certain knowledge of it. And I have knowledge not just of this matter, but of all matters which I remember ever having demonstrated, in geometry and so on.

Sixth Meditation

The existence of material things, and the real distinction between mind and body

Descartes draws a distinction between two modes of thought: imagination, which is concerned with bodily things understood by the mind, but perceived by the senses, and pure understanding, in which the mind “turns towards itself” and the ideas within it.

He reviews in the Sixth Meditation his previous thoughts on the existence of things outside the body and the reliability of the senses. First, since ideas related to sense experience were unwilled, not controllable by intellect, he thought they must arise from an outside source; though he could not rule out that there was some other mechanism within himself at play. Later, demonstrated mistakes of the senses “undermined all the faith [he] had” in them. After all this, with “better knowledge of myself and the author of my being,” he comes to a moderate position: while the senses are not to be trusted outright, not everything need be doubted. With this he reaffirms his earlier notion: the active faculty producing the ideas of sensible objects cannot be in him, since it does not rely on intellectual acts, and man is a thinking thing:

. . . the only alternative is that it is in another substance distinct from me — a substance which contains either formally or eminently all the reality which exists objectively in the ideas produced by this faculty.

This argument was initially dismissed, since we could not be sure that there was not another, unknown faculty within oneself that produced such ideas. But “if the ideas were transmitted from a source other than corporeal things,” God must be a deceiver, and we know he is not. So corporeal things exist. To square their reality with the untrustworthiness of the senses, Descartes notes that corporeal things “may not all exist in a way that exactly corresponds with my sensory grasp of them, for in many cases the grasp of the senses is very obscure and confused. But at least they possess all the properties which I clearly and distinctly understand,” as before.

The body, now known to exist, is linked to the mind, forming a cohesive unit. One does not just steer their body as they would a ship, for we have sensations which affect us according to the state of the body: “pain, hunger, thirst and so on.” The mind is said to be affected only by the brain, or a part of the brain (the one with “common sense?”), and the nervous system sends messages to that part from the rest of the body. While these bodily sensations seem sometime in error, such as someone with fluid build-up (dropsy) feeling thirst while it would harm them to drink, each of these sensations is tuned to their most useful functions in the general case.

Just as the will extended beyond the intellect proved a human mistake rather than a flaw in the abilities themselves, the sensory perceptions are said to have the purpose of “inform[ing] the mind of what is beneficial or harmful for the composite of which the mind is a part,” but have been misused as “touchstones for immediate judgements about the essential nature of the bodies located outside us.”

Concluding the Meditations, on the existence of material things:

I ought not to have even the slightest doubt of their reality if, after calling upon all the senses as well as my memory and my intellect in order to check them, I receive no conflicting reports from any of these sources. For from the fact that God is not a deceiver it follows that in cases like these I am completely free from error. But since the pressure of things to be done does not always allow us to stop and make such a meticulous check, it must be admitted that in this human life we are often liable to make mistakes about particular things, and we must acknowledge the weakness of our nature.