Let me jump to about 1637 AD for another example of the pottiness of Philosophy: ‘Cogito ergo Sum’ – ‘I think, therefore I am’ – wrote Descartes. Descartes couldn’t convince himself he existed till it occurred to him that he was thinking! Therefore he must exist! Did he really think as an adult person that he couldn’t believe he existed until the logic of words proved it?
But, he later changed his mind completely, and said he could after all trust his senses that he exists, and discarded Cogito ergo sum! He is famous for Cogito but he discarded it.
His initial argument that he can’t trust his senses because they had sometimes let him down (see below), is feeble. And his later proof that God exists, derived from Anselm, is even more so. That God exists leads to the conclusion that he can trust the senses that He gave him. It is a litany of silliness of argument.
Philosophers have written about Descartes that he was sceptical to the point that he couldn’t trust the philosophizing of the previous 2000 years. None of it gave him absolute certainty. He wished to start all over again with a self-evident axiom he could be absolutely certain of, and then work forwards from that by deductive logic to establish other certainties as in mathematics. This was his ‘methodological scepticism’, or what he called his ‘mathematical method’. (Didn’t he consider the philosophers of the previous 2000 years to have been as rigorous truth-seekers as he was himself?)
‘Cogito ergo Sum’ didn’t lead him to the conclusion that he, as body and mind, existed. It was only his mind, which was doing the thinking, that existed! And from that logical certainty, and only from that, did he think he could ever arrive at other truths, and by way of logical deduction. He couldn’t trust what came to him through his senses because his senses sometimes proved wrong. So he couldn’t believe that his body existed because his senses may be fooling him that he had arms and legs.
These thoughts of Descartes seem to me pottily rationalistic to the point of irrationality. So I may well have got his thoughts, and their further sequence, not exactly correct in what follows below.
Descartes saw that his senses sometimes proved wrong. For instance, honey was runny when warm, solid when cold, yet was still honey! Descartes also reasoned that it was possible that what came to him through his senses might be in a dream; or that God or a wicked demon might be deceiving him in his sensations. But, even if a demon were deceiving him, his mind would still have to exist for this demon to be deceiving it (see here.)
(But, as I think Ayn Rand, who took philosophy seriously, sanely pointed out: we all rely on our senses to correct the few occasions when our senses temporarily deceive us.)
The Cogito, as described above, adds up to saying that Descartes made a logical inference from the fact of his thinking to the existence of an agent doing the thinking. That’s pretty obvious! But subsequent philosophers go further and say that Descartes also thought of ‘Cogito ergo Sum’ as ‘the certainty of first-person experience’ or ‘intuition of his own reality’ or ‘logical self-certification of self-conscious awareness in any form’ (This comes from http://www.philosophypages.com/ on Descartes but I can’t now trace precisely where on this site.)
This all seems to mean that Descartes had an intuition, separate from his logicking on the subject, that his mind, existed! (Whatever next are philosophers going to think of!)
It seems that Descartes himself wrote that ‘I am’ is an immediate intuition and not the result of a line of reasoning about which he could be deceived; therefore it is certainly true , presumably because it is a clear and distinct perception, from here. This seems to mean that he could trust his senses that he, as mind and body, existed. (To me however, Cogito ergo Sum is an argument. In fact, Descartes did later write that the Cogito is a syllogism whose two premises are ‘I think’ and ‘Whatever thinks, must exist’.)
So, in the above paragraph, I touch on Descartes coming to believe in the perceptions of his senses, which is in direct contradiction to ‘Cogito ergo sum’.
It has been pointed out (here) that Descartes at the Cogito stage of his philosophizing could be defined as an ‘epistemological idealist’ in that he was sure only that his mind existed, and that the external world was just an idea or picture in that mind and may not really exist at all.
It seems some modern philosophers are still worrying whether his Cogito ergo Sum is actually fully logical.
How cretinous it is that all this counts as Philosophy!
The way I’ve presented Descartes’ arguments may not be true to his life and the order his arguments came to him.