Cartesian doubt refers to the opposite of trust in Nguyen’s sense

Descartes, in his meditations, wishes to find a foundation of knowledge that will still stand strong even after doubting the most basic facts about the world. In doing so, he starts by methodically doubting all things that he has “less than complete certainty” of. He casts asides sensory experience, claiming that these can be deceived. Even objects close by could be illusory as he could be dreaming. Even basic axioms of the world like mathematics could be false because of some evil genius that has “employed all his energies in order to deceive me”. Iteratively, he tries to re-prove existence of many things, starting from the existence of self (“cogito, ergo sum”) and progressing towards an argument for the existence of God (and god as a perfect being who cannot be a deceiver.)

First Meditation

Descartes wants to find a foundation of knowledge that will still stand strong even after doubting the most basic facts about the world. Everything he has accepted has true has come through senses, but senses can deceive

First Argument

  1. Some experiences are deceptive (e.g. visual illusions, mirages)
  2. Any particular experience I have might be deceptive
  3. It is possible that all my experiences are deceptive

Counterexample to first argument

  • Some paintings are forgeries
  • Any particular painting might be a forgery
  • It is possible that all paintings are forgeries
  • That can’t be possible because all paintings if all paintings are forgeries, what are they based off of?
  • Cannot dream things that have no component real parts (even mermaids, for example are part women and fish)
  • Some universal axioms still hold
    • “For whether I am awake or asleep, two plus three make five, and a square does not have more than four sides.” (p. 15)

Descartes’ objection to the First Argument

  • Premise 2 doesn’t work!
  • I am sure of my own thoughts. To have these doubts, one must exist. For an evil demon to mislead him in all these insidious ways, he must exist in order to be misled.
  • Therefore, thought above all else is inseparable from being. The Meditator concludes that, in the strict sense, he is only a thing that thinks.

Dream Argument

  1. I have dreamt at being at my desk
  2. When I dreamt it, I believed it was true
  3. When I dreamt it, it was false
  4. There is no way to tell whether you are dreaming or awake
  5. Conclusion: I don’t know that I am here at my desk right now

As premise 4 is roughly equivalent to the conclusion, this argument is invalid. It begs the question (argument which has a premise as a conclusion, circular reasoning)

The God argument

Suppose there exists an evil demon, just as powerful as God, but which deceives me about everything he can

However, it seems possible for there to be such a person. If there were such a person, then everything I believe would be false. I can’t tell that there isn’t such a person. So, I don’t really know anything I thought I knew.

Second Meditation

I am, I exist is necessarily true whenever it is put forward by me or conceived in my mind. For one to be deceived, one must first exist

What is “I”? Soul and body can be deceptions. Thought then, above all else, is inseparable from being

Third Meditation

To assure himself that he is not deceived, he must inquire into the nature of God. Before doing this, the Meditator needs to classify his thoughts

  • Ideas: images of things
    • 3 sources for ideas
      1. Innate
      2. Adventitious: coming from ‘outside’ us (as with our sensory perceptions)
        • His will has no effect on adventitious ideas: he cannot prevent himself from feeling hot when it is hot simply through the will, for instance.
      3. Invented
  • Volitions, emotions, judgements: idea is the object of the thought, and a further thing such as an affirmation or a fear which is directed towards the object of thought

One of the grave mistakes is to judge the ideas in one’s mind to be accurate resemblances of things outside the mind (if they do even exist). Thus the meditator considers ideas in the mind only as modes of thought. Ideas, as modes of thought, all have the same amount of formal reality (reality intrinsic to themselves) but their objective reality differs greatly

For Descartes and the Scholastics, ideas are the link that connect mind and world because they have both formal and objective reality. We can think about this like dividing reality into a scale where infinite substances (like God) have the most reality, followed by finite substances (bodies and minds), followed by modes (modifications of body and mind — e.g. colour, shape, size, etc.).

Ideas then, have the formal reality of modes (as they are modifications of the mind) but objective reality of a finite substance (car is a body). No effect can have a greater amount of reality than its cause. The idea of a stone, then, could be caused by a stone or a large rock but it could not be caused by a colour. If the meditator can locate an idea with more objective reality than he has formal reality (finite substance). The only thing with more reality is infinite substance or the idea of God

Qualia can only be perceived in a confused and obscure way, so if they are things, they must have small degree of reality as to originate unproblematically from the Meditator himself

Existence of God

As the Meditator cannot have originated the concept of God (which has infinite substance), God must be the cause of this idea and must therefore exist

Could God not just be in contrast to his own finite being? We would not be aware of a lack unless we were aware of a more perfect being and God is the ultimate perfect being. You can’t actually get the idea of infinity just from endlessly increasing what’s finite, so the infinite must independently exist (p. 32)

Could the Meditator themselves be supremely perfect? If this is the case, it is plausible that the idea of God could be conceived in him without any outside cause

Rejects this for 3 reasons

  1. God is all actual and not potential
  2. If he is constantly improving, he will never attain perfection while there is room for improvement
  3. Potential is not being at all

The Meditator seems committed to claiming both (a) that we can only be sure of our clear and distinct perceptions if God exists and (b) we can know that God exists because we clearly and distinctly perceive the idea of God. If both (a) and (b) are true, Descartes is guilty of circular reasoning.

Fourth Meditation

If God has endowed him with infallible judgment, how is it that he can be mistaken, as he undoubtedly is from time to time

If God is a perfect creator, God should be able to create perfect beings. The Lord works in mysterious ways — we should not seek to understand the true motives of God (?) Perhaps we are only a small part of a much larger creation

Descartes is a proponent of free will. The will is free to affirm or deny whatever it wishes — as such, free will is the source of error. If there was no free will, we would never make mistakes

Fifth Meditation

In the Fifth Meditation, Descartes presents the argument as follows:

  1. Suppose there is a supremely perfect being — a being that has every possible ‘perfect’ trait. A supremely perfect being must have every possible perfect trait because to exclude any or all perfections from a supremely perfect being is to stumble into a contradiction or to “conceive of a mountain without a valley”.
  2. Necessary existence is a perfection. It is an existence where one depends only on the self for existence (similar to the concept of independent origination in emptiness).
  3. Necessary existence cannot be separated from the essence of a supremely perfect being.
  4. Therefore, a supremely perfect being exists — it is God.

However, this argument is flawed as it begs the question — the premise (that there exists a supremely perfect being) is also the conclusion (a supremely perfect being exists). This inherent circular argument then does not hold.

For the sake of continued examination of the argument, let us assume that this argument is sound, and that God indeed does exist.

Descartes goes on to utilize the statement that God exists to prove that God cannot be a deceiver.

  1. God exists and is perfect
  2. Deception is imperfect, therefore God cannot deceive
  3. Whatever I perceive “clearly and distinctly” must be true
  4. As my perception is clear, the material world must exist

However, this argument also begs the question as it relies on the first proof that God necessarily exists as a premise. Unfortunately, Descartes first proof relies on the fact that Descartes has a clear and distinct idea of God, which presupposes clear and distinct perception (the conclusion of this argument). Thus, to show that his perception is clear, he must assume that his perception is clear — clearly an invalid argument.