That child whose mother has never smiled upon him is worthy neither of the table of the gods nor the couch of the goddesses.

Change is the essence of life.

To imagine is everything, to know is nothing at all.

Ignorance and error are necessary to life, like bread and water.

It is well for the heart to be naive and for the mind not to be.

The wonder is, not that the field of stars is so vast, but that man has measured it.

We find it hard to picture to ourselves the state of mind of a man of older days who firmly believed that the Earth was the centre of the Universe, and that all the heavenly bodies revolved around it. He could feel beneath his feet the writhings of the damned amid the flames; very likely he had seen with his own eyes and smelt with his own nostrils the sulphurous fumes of Hell escaping from some fissure in the rocks. Looking upwards, he beheld ... the incorruptible firmament, wherein the stars hung like so many lamps.