La base primera de la filosofía cartesiana es el cogito ergo sum: pienso, luego soy.

Descartes, reasoning unconsciously according to the prejudices of the old metaphysics, and seeking an unshakable foundation for philosophy, an aliquid inconcussum, as it was said, imagined that he had found it in the self, and posited this principle: I think, therefore I am; Cogito, ergo sum. Descartes did not realize that his base, supposedly immobile, was mobility itself. Cogito, I think — these words express movement; and the conclusion, according to the original sense of the verb to be, sum, ειναι, ou חיח, (haïah), is still movement. He should have said: Moveor, ergo fio, I move, therefore I become!

Descartes had his famous cogito ergo sum; but Thomas had added to it with his “Since I doubt, I think; since I think, I exist.” Well, I was certainly full of doubt. Doubt implied self-awareness, and a concern for one’s future. So I was a conscious entity, barring evidence to the contrary. One down.

Cogito ergo sum

"Instead of René Descartes' famous "Cogito ergo sum" (I think, therefore I am), I propose "Communico ergo sum," (I communicate, therefore I exist") as the philosophical proof of man's existence.

One can ask why the I has to appear in the cogito {Descartes’ argument “I think therefore I am.}, since the cogito, if used rightly, is the awareness of pure consciousness, not directed at any fact or action. In fact the I is not necessary here, since it is never united directly to consciousness. One can even imagine a pure and self-aware consciousness which thinks of itself as impersonal spontaneity.

Cogito ergo sum. <i>(I think, therefore I am.)</i>

"Cogito cogito ergo cogito sum — "I think that I think, therefore I think that I am;" as close an approach to certainty as any philosopher has yet made."

Descartes’ dictum: ‘There is nothing so absurd or incredible that it has not been asserted by one philosopher or another.

I am ... cogito ergo sum ... I think, therefore I am.

punto de partida es la duda metódica. La duda cartesiana no es escepticismo, sino un procedimiento dialéctico de investigación, encaminado a desprender y aislar la primera verdad evidente, la primera idea clara y distinta, la primera naturaleza simple.

"Dubito, ergo cogito, ergo sum.

(English: "I doubt, therefore I think, therefore I am")"

By using the term 'thinking substance' in such sharp contrast to 'extended substance' [Descartes] was clearly implying that the various distinct forms appearing in thought do not have their existence in such an order of extension and separation (i.e., some kind of space), but rather in a different order, in which extension and separations have no fundamental significance.

Ich denke also bin ich (cogit ergo sum)