Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science.

Thoroughly conscious ignorance is the prelude to every real advance in science.

Wrongly do men cry out against experience and with bitter re- proaches accuse her of deceitfulness. Let experience alone, and rather turn your complaints against your own ignorance, which causes you to be so carried away by your vain and insensate desires as to expect from experience things which are not within her power!

Blushing is the most peculiar and most human of all expressions.

If numerous species, belonging to the same genera or families, have really started into life all at once, the fact would be fatal to the theory of descent with slow modification through natural selection.

It is always advisable to perceive clearly our ignorance.