But how do you know that the whole world hasn't its meninges, or that there isn't a big or little spider living in some corner of space with threads … - Denis Diderot

The wisest among us is very lucky never to have met the woman, be she beautiful or ugly, intelligent or stupid, who could drive him crazy enough to be fit to be put into an asylum.

As long as the centuries continue to unfold, the number of books will grow continually, and one can predict that a time will come when it will be almost as difficult to learn anything from books as from the direct study of the whole universe. It will be almost as convenient to search for some bit of truth concealed in nature as it will be to find it hidden away in an immense multitude of bound volumes.

No man has received from nature the right to command his fellow human beings.