The assumed instinctive belief in God has been used by many persons as an argument for his existence. But this is a rash argument, as we should thus be compelled to believe in the existence of many cruel and malignant spirits, only a little more powerful than man; for the belief in them is far more general than in a beneficent deity.

It is absurd to talk of one animal being higher than another...we consider those, where the intellectual faculties most developed as the highest. - A bee doubtless would [use] ... instincts as a criteria.

We are not here concerned with hopes or fears, only with truth as far as our reason permits us to discover it.

The most important factor in survival is neither intelligence nor strength but adaptability.

A grand and almost untrodden field of inquiry will be opened, on the causes and laws of variation, on correlation of growth, on the effects of use and disuse, on the direct actions of external conditions, and so forth.

...I have always maintained that, excepting fools, men did not differ much in intellect, only in zeal and hard work; and I still think there is an eminently important difference.

Multiply, vary, let the strongest live and the weakest die.