Meditations on First Philosophy (subtitled In which the existence of God and the real distinction of mind and body, are demonstrated) is a philosophical treatise written by René Descartes first published in Latin in 1641. The French translation was made by the Duke of 
Luynes with the supervision of Descartes and was published in 1647 with the title Méditations Metaphysiques. The original Latin title is Meditationes de prima philosophia, in qua Dei existentia et animae immortalitas demonstratur. The book is made up of six meditations, in which Descartes first discards all belief in things which are not absolutely certain, and then tries to establish what can be known for sure.
The Meditations consist of the presentation of Descartes’ metaphysical system in its most detailed level and in the expanding of Descartes’ philosophical system, which he first introduced in the fourth part of his Discourse on Method (1637). Descartes’ metaphysical thought is also found in the Principles of Philosophy (1644), which the author intended to be a philosophy guidebook.
Meditations
Meditation I
Descartes begins the first meditation by noting the large number of false beliefs which he had adopted in his childhood. It is necessary to start over entirely, he realizes, if he wants to establish anything in the sciences which is firm and likely to last. In order to do this, he will suspend judgment about any of his beliefs which are in any way uncertain. To inspect each belief separately would take too long; he must find some way to undermine all of his beliefs at once.
The first way that Descartes tries to undermine his beliefs is by considering the fact that he remembers that his senses have deceived him before. If he has been misled by sensory information in the past (e.g. he judged that the stick in the water was straight, when in fact it was bent), then he may be deceived now, “and it is prudent never to trust completely those who have deceived us even once.”
Descartes acknowledges, however, that this consideration doesn’t undermine his beliefs very effectively, since it really seems as if he is sitting in his dressing gown by the fire, holding this piece of paper in his hands, and so on. How could his senses be misleading him about these things?
He goes on to suggest more powerful reasons to doubt that his beliefs are true. In general, his method is that of forming skeptical hypotheses. In the first meditation, he considers whether he is mad, dreaming, or deceived by an evil demon. If any of these scenarios were the case, many of his beliefs would be false. For instance, if he were mad, he might believe completely ridiculous things e.g. that his head is a pumpkin (he only considers the possibility that he is mad briefly and then seems to dismiss it). If he were dreaming, it would be false that he is sitting by the fire. He would only be imagining this were true, when in fact he’s lying in bed asleep. Likewise, if there were a powerful being deceiving him, he would believe that there is a sky and an earth and so on, since the demon would make it appear to him as if this is the case, when in fact none of these things exist.
The general form of these arguments is:
If I am dreaming/deceived, then my beliefs are not true.
I don’t know whether I am dreaming/deceived.
So, I don’t know whether my beliefs are true.
Descartes’ goal — as stated at the beginning of the meditation — is to suspend judgment about any of his beliefs which are even slightly doubtful. The skeptical scenarios show that all of the beliefs which he considers in the first meditation, including at the very least all of his beliefs about the physical world, are doubtful. So he decides to suspend judgment. He will henceforth give up all of his beliefs about the physical world. This is very difficult (as anyone who tries it can attest). At the end of the first meditation Descartes compares himself to a prisoner who enjoys an imaginary freedom while asleep, and dreads waking. In the same way Descartes slips back into his old beliefs, and dreads waking to toil “amid the inextricable darkness of the problems [he] has now raised.”
It is important to keep in mind when reading the Meditations that Descartes intends to lead the reader along with him gradually. He begins with skepticism and attempts to offer a solution. Thus, he should not be uncharitably read as contradicting himself when, for instance, he thinks something is doubtful in the first meditation and as certain in the last. Several of his objectors fail to read the meditations as a guide, in which the order of the arguments is important, and so make this mistake.
Meditation II
In Meditation II: On the Nature of the Human Mind, Which Is Better Known Than the Body, Descartes lays out a pattern of thought, sometimes called representationalism, in response to the doubts forwarded in Meditation I. He identifies five steps in this theory:
We only have access to the world of our ideas; things in the world are only accessed indirectly.
These ideas are understood to include all of the contents of the mind, including perceptions, images, memories, concepts, beliefs, intentions, decisions, etc.
The ideas represent things that are separate from themselves.
These represented things are many times “external” to the mind.
It is possible for these ideas to constitute either accurate or false representations.
Descartes argues that this representational theory disconnects the world from the mind, leading to the need for some sort of bridge to span the separation and provide good reasons to believe that the ideas accurately represent the outside world. The first plank he uses in constructing this bridge can be found in the following excerpt:
I have convinced myself that there is nothing in the world - no sky, no earth, no minds, no bodies. Doesn’t it follow that I don’t exist? No, surely I must exist if it’s me who is convinced of something. But there is a deceiver, supremely powerful and cunning whose aim is to see that I am always deceived. But surely I exist, if I am deceived. Let him deceive me all he can, he will never make it the case that I am nothing while I think that I am something. Thus having fully weighed every consideration, I must finally conclude that the statement “I am, I exist” must be true whenever I state it or mentally consider it. (Descartes, Meditation II: On the Nature of the Human Mind, Which Is Better Known Than the Body).
In other words, one’s consciousness implies one’s existence. In one of Descartes’ replies to objections to the book, he summed this up in the phrase, I am, I exist, which is often confused with the famous quote, I think, therefore I am.
Once he has secured his existence, however, Descartes seeks to find out what “I” is. He rejects the typical method which looks for a definition, e.g. Rational Animal, because the words used in the definition would then need to be defined. He seeks simple terms that do not need to be defined in this way, but whose meaning can just be “seen.” From these self-evident truths, complex terms can be built up.
The first of these self-evident truths is Descartes’ proof of existence turned on its head:
But what then am I? A thinking thing. And what is that? Something that doubts, understands, affirms, denies, wills, refuses, and also sense and has mental images. (Descartes, Meditation II: On the Nature of the Human Mind, Which Is Better Known Than the Body).
To define himself further, Descartes turns to the example of wax. He determines that wax isn’t wax because of its color, texture or shape, as all of these things can change and the substance still be wax. Therefore, he distinguishes between ordinary perception and judgment. The reality of the wax is “grasped, not by the senses or the power of having mental images, but by the understanding alone.” When one understands the mathematical principles of the substance, such as its expansion under heat, figure and motion, the knowledge of the wax can be clear and distinct.
If a substance such as wax can be known in this fashion, then the same must be of ourselves. The self, then, is not determined by what we sense of ourselves - these hands, this head, these eyes - but by simply the things one thinks. Thus, one “can’t grasp anything more easily or plainly than [their] mind.”
Meditation III
Building upon the foundation that “I exist,” Descartes seeks to prove that “I am not alone” in Meditation III: On God’s Existence. Along the way, he solves the skeptical problem of the criterion with an argument as follows:
I exist as a thinking thing.
How can I be certain?
Using the “clarity and distinctness” criterion, Descartes then seeks to prove he is not alone by proving that God exists. He chooses this method because without a knowledge of whether God exists or if he is a deceiver, there is no way to discuss the all-powerful deceiver challenge of reality. In order to do this, he first establishes a causal principle: There must be at least as much reality in the cause as there is in the effect. For example, if a thought of an elephant is caused by a picture of an elephant, the picture must have as much reality as the thought. If it were not so, it could not have produced it.
Using this causal principle, Descartes lays out two ontological arguments in Meditation III for the existence of God. The first begins with the fact that each of us has an idea of God and the second begins with the fact that it is true that the self exists.
Argument 1
I have an idea of God (an infinitely perfect substance).
That idea must have a cause.
Nothing comes from nothing.
The cause must have at least as much formal reality as the idea.
I am not infinitely perfect.
I could not be the cause of the idea.
There must be a cause that is infinitely perfect.
God exists.
Argument 2
I exist.
My existence must have a cause.
The cause must be either:
a) myself
b) my always having existed
c) my parents
d) something less perfect than God
e) God
Not a. If I had created myself, I would have made myself perfect.
Not b. Continued existence does not follow from present existence.
Not c. This leads to an infinite regress.
Not d. This idea cannot account for the fact that the idea is of something supreme.
e. God exists.
From these arguments, Descartes feels he has proved he is not alone in the universe as an infinitely intelligent and powerful and perfect substance exists, also. Not only that, but that this God cannot be a deceiver:
The whole argument comes down to this: I know that I could not exist with my present nature - that is, I could not exist with the idea of God in me - unless there were really a God. This must be the very God whose idea is in me, the thing having all of the perfections that I can’t fully comprehend but can somehow reach with thought, who clearly cannot have any defects. From this it’s obvious He can’t deceive - for, as the natural light reveals, fraud and deception arise from defect. (Descartes, Meditation III: On God’s Existence).
Meditation IV
The conclusions of the previous Meditations that “I” and “God” both exist lead to another problem: If God is perfectly good and the source of all that is, how is there room for error or falsehood? Descartes attempts to answer this question in Meditation IV: On Truth and Falsity.
If I’ve gotten everything in me from God and He hasn’t given me the ability to err, it doesn’t seem possible for me ever to err. (Descartes, Meditation IV: On Truth and Falsity).
The framework of his arguments center on the Great Chain of Being, in which God’s perfect goodness is relative to His perfect being. On the extreme opposite end of the scale is complete nothingness, which is also the extremity of evil. Thus, humans are an intermediary between these two extremes, being less “real” or “good” than God, but more “real” and “good” than nothingness. Thus, error (as a part of evil) is not a positive reality, it is only the absence of what is correct. In this way, its existence is allowed within the context of a perfectly inerrant God.
I find that I am “intermediate” between God and nothingness, between the supreme entity and nonentity. Insofar as I am the creation of the supreme entity, there’s nothing in me to account for my being deceived or led into error, but, insofar as I somehow participate in nothing or nonentity - that is, insofar as I am distinct from the supreme entity itself and lack many things - it’s not surprising that I go wrong. I thus understand that, in itself, error is a lack, rather than a real thing dependent on God. Hence, I understand that I can err without God’s having given me a special ability to do so. Rather, I fall into error because my God-given ability to judge the truth is not infinite. (Descartes, Meditation IV: On Truth and Falsity).
Descartes also concedes two points that might allow for the possibility of his ability to err. First, he notes that it is very possible that his limited knowledge prevents him from understanding why God chose to create him so he could make mistakes. If he could see the things that God could see, with a complete and infinite scope, perhaps he would judge his ability to err as the best option. He uses this point to attack the Aristotelian structure of causes. The final cause described by Aristotle are the “what for” of an object, but Descartes claims that because he is unable to completely comprehend the mind of God, it is impossible to completely understand the “why” through science - only the “how.”
I realize that I shouldn’t be surprised at God’s doing things that I can’t explain. I shouldn’t doubt His existence just because I find that I sometimes can’t understand why or how He has made something. I know that my nature is weak and limited and that God’s is limitless, incomprehensible, and infinite, and, from this, I can infer that He can do innumerable things whose reasons are unknown to me. On this ground alone, I regard the common practice of explaining things in terms of their purposes to be useless in physics: it would be foolhardy of me to think that I can discover God’s purposes. (Descartes, Meditation IV: On Truth and Falsity).
Second, he realized that God has the ability to create a large number of things of which he would just be a part. Perhaps the error is only apparent when looking at the individual and is reconciled when looking at the whole.
When asking whether God’s works are perfect, I ought to look at all of them together, not at one isolation. For something that seems imperfect when viewed alone might seem completely perfect when regarded as having a place in the world. Of course, since calling everything into doubt, I haven’t established that anything exists besides me and God. But, when I consider God’s immense power, I can’t deny that He has made - or, in any case, that He could have made - many other things, and I must therefore view myself as having a place in a universe. (Descartes, Meditation IV: On Truth and Falsity).
Lastly, Meditation IV attributes the source of error to a discrepancy between two divine gifts: understanding and will. Understanding is given in an incomplete form, while will (by nature) can only be either completely given or not given at all. When he is presented with a certain amount of understanding and then chooses to act outside of that, he is in error. Thus, the gifts of God (understanding and will) both remain good and only the incorrect usage by him remains as error.
If I suspend judgement when I don’t clearly and distinctly grasp what is true, I obviously do right and am not deceived. But, if I either affirm or deny in a case of this sort, I misuse my freedom of choice. If I affirm what is false, I clearly err, and, if I stumble onto the truth, I’m still blameworthy since the light of nature reveals that a perception of the understanding should always precede a decision of the will. In these misuses of freedom of choice lies the deprivation that accounts for error. And this deprivation, I maintain, lies in the working of the will insofar as it comes from me - not in my God-given ability to will, or even in the will’s operation insofar as it derives from Him. (Descartes, Meditation IV: On Truth and Falsity).
Meditation V
Meditation V: On the Essence of Material Objects and More on God’s Existence begins with the stated purpose of expanding the “known items” of God and self to include outside material objects, Descartes saves that for Meditation VI in lieu of something he deems more fundamental but in the same direction: a discussion concerning the ideas of those external items. Along the way, he stumbles upon another claimed logical proof of God’s existence.
Before asking whether any such objects exist outside me, I ought to consider the ideas of these objects as they exist in my thoughts and see which are clear and which confused. (Descartes, Meditation V: On the Essence of Material Objects and More on God’s Existence).
In pondering these ideas of external objects, Descartes realizes they can be separated into those that are clear and distinct and those that are confused and obscure. The former group consists of the ideas of extension, duration and movement. These geometrical ideas cannot be misconstrued or combined in a way that makes them false. For example, if the idea of a creature with the head of a giraffe, the body of a lion and tail of a beaver was constructed and the question asked if the creature had a large intestine, the answer would have to be invented. But, no matter how you combine or rearrange mathematical properties, the three angles of a triangle will still add up to 180 degrees and the largest side will always be opposite the largest angle. Thus, Descartes discovers that these truths have a nature or essence of themselves, completely independent of one’s thoughts or opinions.
I find in myself innumerable ideas of things which, though they may not exist outside me, can’t be said to be nothing. While I have some control over my thoughts of these things, I do not make the things up: they have their own real and immutable natures. Suppose, for example, that I have a mental image of a triangle. While it may be that no figure of this sort does exist or ever has existed outside my thought, the figure has a fixed nature (essence or form), immutable and eternal, which hasn’t been produced by me and isn’t dependent of my mind. (Descartes, Meditation V: On the Essence of Material Objects and More on God’s Existence).
While thinking about the independence of these ideas of external objects, Descartes realizes that he is just as certain about God as he is about these mathematical ideas. He asserts that this is natural as the ideas of God are the only ideas that imply God’s existenc
