“The history of science, like the history of all human ideas, is a history of irresponsible dreams, of obstinacy, and of error. But science is one of the very few human activities — perhaps the only one — in which errors are systematically criticized and fairly often, in time, corrected. This is why we can say that, in science, we often learn from our mistakes, and why we can speak clearly and sensibly about making progress there.”

“Scientists make mistakes. Accordingly, it is the job of the scientist to recognize our weakness, to examine the widest range of opinions, to be ruthlessly self-critical. Science is a collective enterprise with the error-correction machinery often running smoothly.”

“One of the reasons for its success is that science has a built-in, error-correcting machinery at its very heart. Some may consider this an overbroad characterization, but to me every time we exercise self-criticism, every time we test our ideas against the outside world, we are doing science. When we are self-indulgent and uncritical, when we confuse hopes and facts, we slide into pseudoscience and superstition.”

“Why are these historical observations interesting?...they suggest that we should be careful about attributing our distinction between philosophy and science to earlier thinkers…The examples I have given do raise an interesting question: Why is it that we tend to see such a radical break between philosophy and science, and, more important, should we? The question can be raised directly, without the need for history, as Quine has done. But history brings the point home in an especially clear way: It shows us an assumption we take for granted by pointing out that it is not an assumption everyone makes.”

“Are you really surprised by the endurance of religion? What ideology is likely to be more durable than one that conforms, at every turn, to our powers of wishful thinking? Hope is easy; knowledge is hard. Science is the one domain in which we human beings make a truly heroic effort to counter our innate biases and wishful thinking. Science is the one endeavor in which we have developed a refined methodology for separating what a person hopes is true from what he has good reason to believe. The methodology isn't perfect, and the history of science is riddled with abject failures of scientific objectivity. But that is just the point-these have been failures of science, discovered and corrected by-what, religion? No, by good science.”

“The history of interpretation, the skills by which we keep alive in our minds the light and dark of past literature and past humanity ... is to an incalculable extent a history of error.”