Scientific knowledge is in perpetual evolution; it finds itself changed from one day to the next.

It was while teaching philosophy that I saw how easily one can say ... what one wants to say. ... In fact, I became particularly aware if the dangers of speculation ... It's so much easier than digging out the facts. You sit in your office and build a system. But with my training in biology, I felt this kind of undertaking precarious.

I have always detested any departure from reality, an attitude which I relate to my mother's poor mental health.

Punishment renders autonomy of conscience impossible.

Scientific knowledge is in perpetual evolution; it finds itself changed from one day to the next.

The self thus becomes aware of itself, at least in its practical action, and discovers itself as a cause among other causes and as an object subject to the same laws as other objects.

This means that no single logic is strong enough to support the total construction of human knowledge.