The metaphysical basis (the first source of knowledge, or starting point) for Ayn Rand's Objectivism is reality.
And, I see no disagreement between Rand and Descartes in the "I think, therefore I exist" department.
Hahahahahaha. Neither do I...........just an interesting thought.
I've just always wondered though whether each of these two philosophers got it only half-right ie. two sides of the same coin.
There is a problem, however. Logically (metaphysically) existense precedes both consciousness and the unique human consciousness capable of thought. Epistemologically, the concept of existense, that which we are conscious of, precedes concepts that could question it. If the concept of existense itself is questioned, there is no epistemological basis for doubt, which is a negation of assertion. If nothing is asserted, there is nothing to doubt. If nothing exists, there is nothing to question. To question existense is an example of the "stolen concept" falacy. Existense, not just the concept, must be assumed to question it.
Hank