The best men of the best epochs are simply those who make the fewest blunders and commit the fewest sins.

If there is anything in the world which I do firmly believe in, it is the universal validity of the law of causation.

Ecclesiasticism in science is only unfaithfulness to truth

Creation,' in the ordinary sense of the word, is perfectly conceivable. I find no difficulty in conceiving that, at some former period, this universe was not in existence, and that it made its appearance in six days (or instantaneously, if that is preferred), in consequence of the volition of some preexisting Being.

It is the first duty of a hypothesis to be intelligible.

Within the last fifty years, the extraordinary growth of every department of physical science has spread among us mental food of so nutritious and stimulating a character that a new ecdysis seems imminent.

There is no greater mistake than the hasty conclusion that opinions are worthless because they are badly argued.