"Numbers are the product of counting. Quantities are the product of measurement. This means that numbers can conceivably be accurate because there is a discontinuity between each integer and the next. Between two and three there is a jump. In the case of quantity there is no such jump, and because jump is missing in the world of quantity it is impossible for any quantity to be exact. You can have exactly three tomatoes. You can never have exactly three gallons of water. Always quantity is approximate."

“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.”