Originally posted by Mentat
Yes it may, but not if Entity A doesn't have a mind and cannot think about being convinced by a hypothetical Entity B. IOW, unless Entity A exists, it cannot think about not existing - it thinks therefore it is. However, you would be correct in saying that Descartes' reasoning only validates the belief in his own existence, it does not invalidate Solipsism (or any other Idealistic reasoning), as some think it does.
Dammit! Caught out by careless language again! Let me rephrase that:
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I think you barking up the wrong tree here. The doubt about the existence of Entity A may arise spontaneously
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I think this all boils down to what is meant or implied by 'exist' and what the nature of the knowledge of this existence is.
I don't think anyone really doubts that they are some sort of mentally active 'system', for all reasonable pragmatic purposes at least. But what are the limits to this?
- I might not be who or where I seem to be. I might be in some sort of 'Matrix'. So, the 'I' might not be what I think it is.
- It is not safe to assume these rationality of the thought processes are infallible, the logic could be flawed at any step, and I have no way to check this without continuing to rely on logic
- There is no reason to assume the awareness of the thoughts is perfect. There is only changing appearance of phenomena as with all other phenomena. There is no reference point against which I can check this.
- Each thought might be an illusion, from an external source
From this it seem that it is reasonable to deduce one's own existence from apparent phenomena, it is not reasonable to see one 'self' as special or separate from other phenomena, nor is knowledge of it perfect or fundamentally different to that of other phenomena. Few would question their own existence as an object and mentality, its just the conclusion of the existence of a special existential self that is flawed. Many do not have such a sense of self, including young children, Buddhists and anyone fully absorbed in something or under the influence of certain psychoactive drugs.