The human tendency to regard little things as important has produced very many great things.

Diogenes, filthily attired, paced across the splendid carpets in Plato's dwelling. Thus, said he, do I trample on the pride of Plato. Yes, Plato replied, but only with another kind of pride.

Never undertake anything unless you have the heart to ask Heaven's blessing on your undertaking.

As I take up my pen I feel myself so full, so equal to my subject, and see my book so clearly before me in embryo, I would almost like to try to say it all in a single word.

A book is a mirror: if an ape looks into it an apostle is hardly likely to look out.

There is no greater impediment to progress in the sciences than the desire to see it take place too quickly.

Nothing is more conducive to peace of mind than not having any opinion at all.