Descartes assumes that the essence of a thing can generally be known before one knows whether the thing exists, because the essential properties of a thing are implied by the idea or concept of that thing.
However, this thesis about the essence of the self is yet to be argued for.
You will notice that throughout the , Descartes carefully distinguishes the question of the existence of something, from the question of the essence or nature of that thing.
This process shows a gradual evolution from a state of "natural consciousness" (56) (1) to one of complete self-consciousness - which leads to an understanding of the "nature of absolute knowledge itself" (66).
If it were not an animal, it would not be a cat; if it were not an animal, it would not be a yeti.
If Descartes' argument that the 'I' of the Meditations is essentially a thinking thing is successful, then the implication is similar: if I exist, I must be thinking.
(I am essentially a thinking thing.) This symmetry will be central to Descartes' vision of what it is to be an 'I', a soul, or self, or mind: I am if and only if I think.
Expressing perfect confidence in the capacity of human reason to achieve knowledge, Descartes proposed an intellectual process no less unsettling than the architectural destruction and rebuilding of an entire town.
Non-human , on Descartes's view, are complex organic machines, all of whose actions can be fully explained without any reference to the operation of mind in thinking.
I will like Descartes in his ‘First Meditation’, put these preconceptions to one side and present an essay that explores both sides of the argument in an attempt to reach an independent conclusion.
Descartes says, 'the proposition...I exist, is necessarily true whenever it is...conceived in my mind.' This could be interpreted exactly in line with Williams' suggestion: 'if the proposition 'I exist' is believed by me (conceived in my mind), then it is true'.
Immediately after the conclusion of the , Descartes says: 'I do not yet have a sufficient understanding of what this 'I' is, that necessarily exists' (25).
Descartes considers four of these capacities (coyly omitting reproduction!), and argues that none but the last capacity, thought, is essential to the nature of the soul.
Notice that Descartes appears to believe he has established not only 'I think'; not only 'I am a thinking thing'; not only 'thought is a property essential to me'; but the strong conclusion that 'thought is the property essential to me'.
If so, then the white beard is not essential to him.) Unfortunately it is not quite clear what essence Descartes is trying to discover: it is not quite clear whether he is asking a question about the essential properties of wax in general, or a particular lump of wax, or of matter in generalquestions which would all have different answers (what might they be?).
(For a particularly helpful discussion of the 'wax passage' see John Cottingham, (Blackwell, 1986) 80-81.)
Descartes reaches a conclusion about the essence of matter.
Descartes reaches the apparently radical conclusion that bodies, or rather the essential properties of bodies, are known not by mere sense perception, or imagination, but the intellect: perception always involves judgment.
Descartes's conclusion was objected to by the philosopher Gassendi, and his objection, and the reply Descartes gave, are to be found at 276-7, and 360.