Subjectivism given consciousness is dependent on that consciousness. This has its philosophical basis in the writings of Descartes (see "cogito ergo sum"), and forms a cornerstone of Søren Kierkegaard's philosophy. Recently, more modest versions of metaphysical subjectivism have been explored. For example, I might hold that it is a "fact" that chocolate is tasty, even though I recognize that it is not tasty to everyone. This would imply that there are facts that are "subjective". (Analogously, one might hold that it is a fact that it is winter in the Northern Hemisphere, even though this is not always the case, implying
Cogito, ergo sum of other minds at this point. This is something that has to be thought through by each of us for ourselves, as we follow the course of the meditations. Second, he does not say that his existence is necessary; he says that "if he thinks", then necessarily he exists (see the instantiation principle). Third, this proposition "I am, I exist" is held true not based on a deduction (as mentioned above) or on empirical induction but on the clarity and self-evidence of the proposition. Descartes does not use this first certainty, the "cogito", as a foundation upon which to build