In truth, the laboratory is the forecourt of the temple of philosophy, and whoso has not offered sacrifices and undergone purification there has little chance of admission into the sanctuary.

Extinguished theologians lie about the cradle of every science, as strangled snakes beside that of Hercules

Men can intoxicate themselves with ideas as effectually as with alcohol or with bang and produce, be dint of serious thinking, mental conditions hardly distinguishable from monomania.

Every living creature commences its existence under a form different from, and simpler than, that which it eventually attains.

The birth of science was the death of superstition.

I protest that if some great Power would agree to make me always think what is true and do what is right, on condition of being turned into a sort of clock and would up every morning before I got out of bed, I should instantly close with the offer.

A good man: body serves his will and enjoys hard work, clear intellect that understands the truths of nature, full of passion for life but controlled by his will, well-developed conscience, loves beauty in art and nature, despises inferior morality, respects himself and others.