Cogito ergo sum

"I have convinced myself that there is absolutely nothing in the world, no sky, no earth, no minds, no bodies. Does it now follow that I too do not exist? No: if I convinced myself of something then I certainly existed. But there is a deceiver of supreme power and cunning who is deliberately and constantly deceiving me. In that case I too undoubtedly exist, if he is deceiving me; and let him deceive me as much as he can, he will never bring it about that I am nothing so long as I think that I am something. So after considering everything very thoroughly, I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind." (Med. 2)

There are two things that are important to take out of Descartes' Second Meditation. The first is Descartes' foundational first-principle, 'I think, I exist' (hencforth 'the cogito') upon which he will build his way to knowledge. From the cogito Descartes derives a criterion by which he proposes to determine the certainty and truth of various candidates for belief. He states it explicitly in the Third Meditation:

"I am certain that I am a thinking thing. Do I not therefore also know what is required for my being certain about anything? In this first item of knowledge there is simply a clear and distinct perception of what I am asserting...So I now seem to be able to lay it down as a general rule that whatever I perceive very clearly and distinctly is true." Descartes says that he is able to identify clear and distinct ideas because their truth is revealed to him "by some natural light" and such things he says are "in no way open to doubt," just like the cogito.

A Possible Criticism: Circularity?

"Descartes first argues from clearly and distinctly perceived premises to the conclusion that a non-deceiving God exists; he then argues from the premise that a non-deceiving God exists to the conclusion that what is clearly and distinctly perceived is true. The worry is that he presupposes the C&D Rule in the effort to prove the C&D Rule." (http://plato.stanford.edu/entries/descartes-epistemology/#6)

The Wax Thought Experiment:

Descartes examines his consciousness in search of more clear and distinct ideas in addition to the cogito, beginning with physical bodies, something that people generally think is understood most distinctly of all. He takes a ball of wax and lists all the ways he is able to perceive it with his senses, and then he melts it and is no longer able to perceive it any of the same ways. He concludes that he perceives the wax not with his senses, nor with his imagination (since the wax is capable of mor changes than he can conceive). Descartes concludes that the very idea of body is not a product of the senses or the imagination but an innate idea, understood by the intellect alone and kept in the "storehouse of the mind." In the Third Meditation, Descartes continues his investigation of this storehouse, and the fruits of his labours allow him to move his certainty from beyond the content of his own consciousness to the world outside of him.

Descartes talks about how the innate ideas that he knows by the intellect alone have "greater reality" than those known by the senses. What does this mean? The Stanford Encyclopedia says:

" Descartes' commitment to innate ideas places him in a rationalist tradition tracing back to Plato. Knowledge of the nature of reality derives from ideas of the intellect, not the senses. An important part of metaphysical inquiry therefore involves learning to think with the intellect. The allegory of the cave portrays this rationalist theme in terms of epistemically distinct worlds. Plato likens what the senses reveal to shadowy imagery on the wall of a poorly lit cave—to wit, images of mere figurine beings; he likens what the intellect reveals to a world of fully real beings illuminated by bright sunshine. The metaphor aptly depicts our epistemic predicament, on Descartes' own doctrines. An important function of his methods is to help would-be Knowers redirect their attention from the confused imagery of the senses, to the luminous world of the intellect's clear and distinct ideas."

One such clear and distinct idea that Descartes discovers in the storehouse of his mind is the idea of God. If you remember, when we were discussing Aquinas' cosmological argument, it relied on two principles. Descartes reiterates them in the Third Meditation: 1) "There must be at least as much reality in the efficient and total cause as in the effect of the cause." That is to say that the cause must have the same properties as its effect (Descartes uses a stone for example, a stone must be caused by something made of the same stuff). 2) "Something cannot aries from nothing," or the Principle of Sufficient Reason--every effect must have a cause. From (1) Descaretes deduces that what is more perfect cannot arise from what is less perfect. This means that the idea of God cannot have been produced in Descartes himself, since he is imperfect and finite. Therefore, he concludes that there must be a cause that possesses the properties of "infinite, eternal, omniscience, omnipotence, unity (of all these attributes) and perfection" which Descartes finds in the storehouse of his mind. Descartes calls this cause God.

Descartes' Method of Doubt

Of his own methodology, Descartes writes:

Throughout my writings I have made it clear that my method imitates that of the architect. When an architect wants to build a house which is stable on ground where there is a sandy topsoil over underlying rock, or clay, or some other firm base, he begins by digging out a set of trenches from which he removes the sand, and anything resting on or mixed in with the sand, so that he can lay his foundations on firm soil. In the same way, I began by taking everything that was doubtful and throwing it out, like sand … (Replies 7, AT 7:537) [from http://plato.stanford.edu/entries/descartes-epistemology/#2]

Descartes' method of doubt has two purposes:

1. Eliminate all beliefs that could compromise the possibility of certain knowledge. If any belief is open to doubt, then it makes all other beliefs that rest upon it shaky.
2. Discover a belief or set of beliefs that are beyond all doubt. In removing all beliefs that are open to any kind of doubt, Descartes hopes to be left with indubitable knowledge.

Descartes method of doubt is analogous to a bulldozer, except he uses this bulldozer for construction as well as destruction. It is an epistemic bulldozer, designed to move all unsteady ground upon which a foundation of knowledge could be built. It makes sense then to use the biggest bulldozer possible, so that when that bulldozer hits something that can't be moved, we will know for sure that is the securest foundation for knowledge we can find.

This is why Descartes goes as far as he does in doubting absolutely everything. When he finds a first principle upon which to base the rest of his knowledge he wants to be absolutely certain it is sound.

Descartes' applies this method of doubt to all of his beliefs because if there is even one dubitable belief that escapes his epistemic bulldozer, it threatens the integrity of his beliefs' foundations. To switch analogies for a minute, think about your collection of beliefs as a basket of apples:

Suppose [a person] had a basket full of apples and, being worried that some of the apples were rotten, wanted to take out the rotten ones to prevent the rot spreading. How would he proceed? Would he not begin by tipping the whole lot out of the basket? And would not the next step be to cast his eye over each apple in turn, and pick up and put back in the basket only those he saw to be sound, leaving the others? In just the same way, those who have never philosophized correctly have various opinions in their minds which they have begun to store up since childhood, and which they therefore have reason to believe may in many cases be false. They then attempt to separate the false beliefs from the others, so as to prevent their contaminating the rest and making the whole lot uncertain. Now the best way they can accomplish this is to reject all their beliefs together in one go, as if they were all uncertain and false. They can then go over each belief in turn and re-adopt only those which they recognize to be true and indubitable. (Replies 7, AT 7:481)

There are two different skeptical arguments (or epistemic bulldozers) that Descartes uses to raze his dubious beliefs and construct a firm foundation for knowledge.

1. Dreaming Doubt: Rests on the assumption of some degree of similarity between dreaming and waking life. This denies only that there is indubitable certainty that one is awake, because it is conceivable that one could be having a lucid dream identical with waking. This holds even though one might very well be awake.

2. Evil Genius: The dreaming doubt demolishes the certainty of beliefs based on sensory experience, but that still leaves other beliefs that are dubious. This could be described as the "What if I'm just a mind in a vat/matrix?" doubt. But this doubt goes further, in that it stands to undermine the certainty of even the most basic logical and mathematical truths. For the Evil Genius could cause us to be deceived about even these things.

The Ontological Argument (Tutorial Group Write-up) [For a comprehensive account of my lecture notes and a discussion of Gaunilo's Island Objection see below.]


1. a)
God is the greatest conceivable being.
God exists in the mind.
Existance is a great-making quality.
.:It is an absurdity to conclude that God does not exist in reality, as
that would mean the greatest conceivable being could, conceivably, be
greater if it existed, making that which is only in the mind the second
greatest conceivable being.

b)
The most obvious flaw in Anselm's argument is his presumption that
existance is a greatmaking quality. If you can fully conceive of
something in your mind, its mere existance in reality is not going to
impress you any more. This is only the case if you have in fact not
fully conceived it.
To use a typical example: there is no cure for AIDS. Some say that if a
person could form an exact mental image of what the cure would be (how
it would look, how it would work, what it was made from, etc) the
resulting cure would be inferior to an identical counterpart that
existed in reality.
I would argue that if a concept is a fully identical and accurate conception of its object, then the object's existence in reality cannot make the concept any greater than it already is [see Kant's Thalers example below for another account of this.]. If I see a diamond ring in an ad, and then
receive the same ring for Christmas, it is not the ring that has
changed and become greater, but my reactions to it. Likewise, a cure
for Aids would not be greater if it existed in reality; the lives of
the people affected by Aids, and consequently cured, would be altered.
If this premise of Anselm's argument is false, the whole argument
collapses. The absurd conclusion that is necessary to reach his real
intended conclusion is no longer an issue. If existance is not a
great-making quality, then it is perfectly acceptable that the greatest
conceivable being might only exist in ones mind.

The Problem of Evil (Tutorial Group Write-up)

Johnson uses the existence of evil to argue that God doesn’t exist.
His argument is as follows: P1. If evil exists, God can’t be tri-omni'ed (That is omnipotent, omniscient & omnibenevolent...[Here explain why evil is incompatible with God being triomnied.]). P2. Evil exists [Here it would be best to specify what sort of evil exist and why we God is accountable for them]. C: Therefore God isn’t tri-omni'ed (by Modus Ponens).

He realizes that if one part of the tri-omni claim is dropped then perhaps the two are reconcilable. For example, perhaps God simply does not know the baby is burning in the house and therefore is not omniscient. This however does not satisfy many theologians, not in the least...

For (b): From here it would be best to detail the objections to the argument made by Swinburne, and to determine whether or not they succeed.

The Cosmological Argument (Tutorial Group Aquinas Write-up)

Aquinas argument for the existence of god:
Change:
-all things change
-all things are in the process of change
-something is always in the process of change
-things in the process of change are not yet fully what they should be ( not
fulfilling their potential)
-change has to start from somewhere--) chain
-the cause changes something to be another thing ( example: fire- which is
actually hot, causes wood which can potentially be hot, to become actually
hot. Therefore, there is a change in the wood)
-objects cannot change itself-something has to cause it to change
-chainà something else is changing something, and the something is being
changed by something else ( ect)
-the chain must stop somewhere, otherwise there will be no 1st cause of the
chain
-without a 1st cause, there will be no change
(Ex: if the hand doesn’t move the stick, then the stick will not move.)
-what causes this chain is unknown, therefore, is must be a greater power that
does not depend on anything.

The Cosmological Argument (Supplement)

The cosmological argument proceeds in two steps. The first part claims the existence of a necessary being, a first cause of all things. The second part of the argument seeks to establish that that being is God. We are only dealing with the first part of Aquinas's argument. I will follow Rowe in using the phrase "dependent being" to mean "a being which has the reason for its existence in the causal efficacy or nature of some other being" and the expression "indpendent being" to mean "a being which has the reason for its existence within its own nature."

The cosmological argument depends on acceptance of a strong form of the Principle of Sufficient Reason, which states that not only those beings which begin to exist must have a cause of explanation (the weak form of the PSR) but that absolutely every being must have an explanation of its existing rather than not existing.

This is how Rowe states the argument:

1. If every being is dependent then the whole of existing things consists of an infinite collection of dependent beings;
2. If the whole of existing things consists of an infinite collection of dependent beings then the infinie collection itself must have an explanation of its existence;
3. If the existence of the infinite collection of dependent beings has an explanation then the explanation must lie either in the causal efficacy of some being outside the collection or it must lie within the infinite collection itself;
4. The explanation of the existence of the infinite collection of dependent beings cannot lie in the causal efficacy of some being outside the collection;
5. The explanation of the existence of the infinite collection of dependent beings cannot lie within the collection itself; therefore,
6. There is no explanation of the infinite collection of dependent beings (from 3, 4, 5); therefore,
7. It is false that the whole of existing things consists of an infinite collection of dependent beings (from 2 and 6); therefore
8. It is false that every being is dependent.