If we do not allow free thinking in chemistry or biology, why should we allow it in morals or politics?

The dead govern the living.

Nothing is destroyed until it is replaced.

All good intellects have repeated, since Bacon's time, that there can be no real knowledge but that which is based on observed facts. This is incontestable, in our present advanced stage; but, if we look back to the primitive stage of human knowledge, we shall see that it must have been otherwise then. If it is true that every theory must be based upon observed facts; it is equally true that facts can not be observed without the guidance of some theory. Without such guidance, our facts would be desultory and fruitless; we could not retain them: for the most part we could not even perceive them.

The sacred formula of positivism: love as a principle, the order as a foundation, and progress as a goal.

In mathematics we find the primitive source of rationality; and to mathematics must the biologists resort for means to carry out their researches.

All good intellects have repeated, since Bacon's time, that there can be no real knowledge but which is based on observed facts.