One must judge men not by their opinions, but by what their opinions have made of them.

Most men of education are more superstitious than they admit - nay, than they think.

The Greeks possessed a knowledge of human nature we seem hardly able to attain to without passing through the strengthening hibernation of a new barbarism.

The noble simplicity in the works of nature only too often originates in the noble shortsightedness of him who observes it.

One has to do something new in order to see something new.

We have to believe that everything has a cause, as the spider spins its web in order to catch flies. But it does this before it knows there are such things as flies.

Nothing puts a greater obstacle in the way of the progress of knowledge than thinking that one knows what one does not yet know.