“Scientific knowledge is a body of statements of varying degrees of certainty -- some most unsure, some nearly sure, none absolutely certain.”

“I do not rest on the broad upland of a system that includes a series of sure statements about the absolutes, but on a narrow, rocky ridge between the gulfs where there is no sureness of expressible knowledge but [only] the certainty of meeting what remains, undisclosed.”

“Dogmatism and skepticism are both, in a sense, absolute philosophies; one is certain of knowing, the other of not knowing. What philosophy should dissipate is certainty, whether of knowledge or ignorance.”

“Some care is needed in using Descartes' argument. "I think, therefore I am" says rather more than is strictly certain. It might seem as though we are quite sure of being the same person to-day as we were yesterday, and this is no doubt true in some sense. But the real Self is as hard to arrive at as the real table, and does not seem to have that absolute, convincing certainty that belongs to particular experiences.”

“10% ago I was 90% unsure of what I didn’t want to do. Now I’m just 33.3% sure that I’m 66.6% unsure. And I can say this with .1% certainty.”

“Surely there is a knowing behind it all. There is a teacher, an expresser, a creator, an artist perhaps, a poet certainly that has designed and presented all of the clues that we need to navigate life with some degree of grace, and perhaps with a greater degree of happiness than we now have.”