  Santayana’s critique of epistemological foundationalism is as unique as his heritage. With Spanish irony, he structures his argument after Descartes’ Meditations but arrives at an anti-foundationalist conclusion. Drawing attention to what is given in an instant of awareness (the smallest conceivable moment of consciousness), he maintains that any knowledge or recognition found in such an instant would have to be characterized by a concept (or “essence” to use Santayana’s term). Concepts cannot be limited to particular instances; rather the particular object is seen as an instance of the concept (essence). Thus, pursuing doubt to its ultimate end, one is confined by the “solipsism of the present moment.” That is, in a single instant of awareness there can be no knowledge or belief, since both require concepts not bounded by a moment of awareness. Hence, the ultimate end of doubt, an instance of awareness, is empty. It is the vacant awareness of a given without a basis for belief, knowledge or action. Santayana concludes that if one attempts to find the bedrock of certainty, one may rest his claim only after he has, at least theoretically, recognized that knowledge is composed of instances of awareness that in themselves do not contain the prerequisites for knowledge, e.g., concepts, universals, or essences. That both skepticism and proofs against skepticism lead nowhere is precisely Santayana’s point.