I am a firm believer, that without speculation there is no good and original observation..

Even the humblest mammal's strong sexual, parental, and social instincts give rise to 'do unto others as yourself' and 'love thy neighbor as thyself'..

...one doubts existence of free will [because] every action determined by heredity, constitution, example of others or teaching of others." "This v….

The tree of life should perhaps be called the coral of life, base of branches dead; so that passages cannot be seen-this again offers contradiction t….

Among the scenes which are deeply impressed on my mind, none exceed in sublimity the primeval [tropical] forests, ... temples filled with the varied ….

Hereafter we shall be compelled to acknowledge that the only distinction between species and well-marked varieties is, that the latter are known, or ….

Intelligence is based on how efficient a species became at doing the things they need to survive..

I hate a Barnacle as no man ever did before, not even a Sailor in a slow-sailing ship..

As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I beli….

The more we know of the fixed laws of nature the more incredible do miracles become, - that the men at that time were ignorant and credulous to a deg….

My mind seems to have become a kind of machine for grinding general laws out of large collections of facts..

At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate and replace throughout….

It occurred to me, in 1837, that something might perhaps be made of this question (the origin of the species) by patiently accumulating and reflectin….

I suppose you are two fathoms deep in mathematics, and if you are, then God help you. For so am I, only with this difference: I stick fast in the mud….

If Mozart, instead of playing the pianoforte at three years old with wonderfully little practice, had played a tune with no practice at all, he might….

[Alexander von Humboldt was the] greatest scientific traveller who ever lived..

Why does man regret, even though he may endeavour to banish any such regret, that he has followed the one natural impulse, rather than the other; and….

It is really laughable to see what different ideas are prominent in various naturalists' minds, when they speak of 'species'; in some, resemblance is….

It has sometimes been said that the success of the Origin proved "that the subject was in the air," or "that men's minds were prepared for it." I do ….

I have steadily endeavored to keep my mind free so as to give up any hypothesis, however much beloved (and I cannot resist forming one on every subje….

Mr. J.S. Mill speaks, in his celebrated work, "Utilitarianism," of the social feelings as a "powerful natural sentiment," and as "the natural basis o….