a bit of knowledge without justification on santayana's argument that empirical knowledge, including science, rests on faith:
In Scepticism and Animal Faith Santayana goes so far as to assert that all knowledge is faith precisely because we are never in a position decisively to refute scepticism, that is, to remove objective uncertainty. Santayana sets out the familiar sceptical arguments elaborately, and in fact endorses their conclusions. That is, he affirms that we are in a position, as far as the exercise of reason with no assumptions is concerned, of radical and unrelievable doubt as to the existence of the external world, the deliverances of memory, even as to the existence or at least the nature of the subject. Or rather, if we were in fact creatures that generated beliefs by the emotionless exercise of reason with no assumptions, our doubts would be radical and unrelievable. But as agents, as passionate, individual creatures of the sort we are, we happen in fact to be under no serious doubt about these things. (The similarity of the position under consideration to the "naturalized" epistemology of Quine and others should here be remarked. Like Kierkegaard and Santayana, proponents of that project hold that scepticism is irrefutable and that how we actually come to acquire beliefs is relevant to how we ought to acquire them. And the similarity of the position to my reading of Diogenes, Johnson, and Moore need hardly be emphasized.) Santayana says: "the scepticism I am defending is not meant to be merely provisional; its just conclusions will remain fixed, to remind me perpetually that all alleged knowledge of matters of fact is faith only."(20)
This does not mean that all factual claims are wholly unjustified. Rather, Santayana's view is that all such claims rest finally on beliefs for which no justification can be produced. Knowledge, says Santayana, is faith mediated by signs. We take our intuitions to be signs of external objects and events. Taken in that way, such intuitions can lead to justified beliefs. But there is no justification for taking them that way. Animal faith, then, consists in the treatment of intuitions as signs of the external world, in "supposing that there is substantial there, something that will count and work in the world" (SAF p.39)