Descartes begins Part I of the Principles by calling all of our beliefs into doubt. This exercise is meant to free us from our reliance on the senses, so that we can begin to contemplate purely intellectual truths.
The doubting is initiated in two stages. In the first stage, all the beliefs we have ever received from sensory perceptions are called into doubt. In the second stage, even our intellectual beliefs are called into doubt.
Descartes presents two reasons for doubting that our sensory perceptions tell us the truth. First of all, our senses have been known to deceive us. Examples of the sort of systematic deception he has in mind here include phenomena such as the bent appearance of a straight stick when viewed in water and the optical illusion of smallness created by distance. The second doubt that Descartes brings to bear on sensory perceptions is more dramatic. Descartes claims that even in optimal viewing conditions (i.e. close by, no intervening water, etc.) we cannot trust our senses. The reason is that when we sleep we often have sensations indistinguishable from those that we have when we are awake. We admit that those dreaming sensations do not correspond to reality, so why are we any more certain of our waking sensations? How do we know that any particular sensation is not just a dream, a sensation stemming from causes unbeknownst to us? This second argument is popularly referred to as the "Dreamer Argument."
Descartes next casts doubt onto our mathematical demonstrations and other self- evident truths. In order to do this, he first points out that people are sometimes known to make mistakes when it comes to these subjects. In addition, he claims, for all we know, God (or some lesser being) is manipulating our thoughts, causing things to seem certain when really they are not. This argument is commonly referred to as the "Evil Demon Argument".
After attempting to undermine all of our beliefs, Descartes identifies one belief that resists all such attempts: the belief that I myself exist. This stage in Descartes' argument is called the cogito, derived from the Latin translation of "I think." It in only in the Principles that Descartes states the argument in its famous form: "I think, therefore I am." This oft- quoted and rarely understood argument is meant to be understood as follows: the very act of thought proves existence, because one cannot possibly think without existing.
The cogito is arguably the most famous argument in philosophy, but what is it really supposed to prove? What is Descartes' purpose in beginning his magnum opus with such a trivial piece of knowledge? In order to see the answer to this question, it is important to view the cogito in its context.
Presentation on theme: "An Outline of Descartes's Meditations on First Philosophy"— Presentation transcript:
1 An Outline of Descartes's Meditations on First Philosophy
Descartes’ Arguments for Universal Doubt and the "Cogito" Argument (An Outline of Meditations 1,2)
2 The argument for universal doubt: The dream argument: I often have perceptions very much like the ones I usually have in sensation while I am dreaming.
3 There are no definite signs to distinguish dream experience from waking experience. therefore
4 It is possible that I am dreaming right now and that all of my perceptions are false
5 The deceiving God argument: We believe that there is an all powerful God who has created us and who is all powerful.
6 He has in his power to make us be deceived even about matters of mathematical knowledge which we seem to see clearly. Therefore:
7 It is possible that we are deceived even in our mathematical knowledge of the basic structure of the world.
8 Objections to the deceiving God argument:
We think that God is perfectly good and would not deceive us.
9 Some think that there does not exist such a powerful God.
10 The demon argument: Instead of assuming that God is the source of our deceptions, we will assume that there exists an evil demon, who is capable of deceiving us in the same way we supposed God to be able
11 Therefore, I have reason to doubt the totality of what my senses tell me as well as the mathematical knowledge that it seems I have.
12 The Argument for our Existence (the "Cogito"):
Even if we assume that there is a deceiver, from the very fact that I am deceived it follows that I exist.
13 In general it will follow from any state of thinking (e. g
In general it will follow from any state of thinking (e.g., imagining, sensing, feeling, reasoning) that I exist. While I can be deceived about the objective content of any thought, I cannot be deceived about the fact that I exist and that I seem to perceive objects with certain characteristics.
14 Since I only can be certain of the existence of myself insofar as I am thinking, I have knowledge of my existence only as a thinking thing (res cogitans).I THINK, THEREFORE, I AMCogito Ergo sum
15 The Argument God Exists In my mind I have a clear idea of a perfect entity (God) and this idea has objective reality
16 The idea of God could not have originated in me, since I am a finite substance
The idea of a perfect God could not have come from me as I am imperfectTherefore:
17 The idea of God must have originated from that perfect Entity itself ( ie, from God)
18 Therefore:God Exists
19 “The Mind-Body Problem” It is possible that all knowledge of external objects, including my body, could be false if I am being tricked by an evil demon However, I cannot be deceived about my existence or my nature as a thinking thing( because I know that I exist)
20 Yet a Perfect God would not deceive us
Therefore:Therefore, what we perceive with our Reason is Reality
21 Outer Reality is different than the reality of thought
Thought– MINDExtension– MATTERBoth of these originate from God because only God exists independently from anything else
22 All Knowledge of External Reality is in the Mind
Wax example:All the properties of wax that we perceive with the senses change as the wax meltsYet the Wax remains “Wax” even though it looks, feels and smells differentWe know that it is Wax through our mind, not through our senses
23 The mind is superior to the body
Human Beings have the capacity to rise above bodily needs and behave RATIONALLY