"Science, like art, religion, commerce, warfare, and even sleep, is based on presuppositions. It differs, however, from most other branches of human activity in that not only are the pathways of scientific thought determined by the presuppositions of the scientists but their goals are the testing and revision of old presuppositions and the creation of new."

“Epistemology is always and inevitably personal. The point of the probe is always in the heart of the explorer: What is my answer to the question of the nature of knowing?”

“In the transmission of human culture, people always attempt to replicate, to pass on to the next generation the skills and values of the parents, but the attempt always fails because cultural transmission is geared to learning, not DNA.”

“We do not know enough about how the present will lead into the future. We shall never be able to say, "Ha! My perception, my accounting for that series, will indeed cover its next and future components," or "Next time I meet with these phenomena, I shall be able to predict their total course.”

“Perhaps the attempt to achieve grace by identification with the animals was the most sensitive thing which was tried in the whole bloody history of religion.”

“Let's not pretend that mental phenomena can be mapped on to the characteristics of billiard balls.”

“If a man achieves or suffers change in premises which are deeply embedded in his mind, he will surely find that the results of that change will ramify throughout his whole universe.”