It is a fatal fault to reason whilst observing, though so necessary beforehand and so useful afterwards.

When the views entertained in this volume on the origin of species, or when analogous views are generally admitted, we can dimly forsee that there will be a considerable revolution in natural history.

Music was known and understood before words were spoken.

I have just finished my sketch of my species theory. If as I believe that my theory is true & if it be accepted even by one competent judge, it will be a considerable step in science. I therefore write this, in case of my sudden death, as my most solemn & last request, which I am sure you will consider the same as if legally entered in my will, that you will devote 400£ to its publication & further will yourself, or through Hensleigh [Wedgwood], take trouble in promoting it.

... if variations useful to any organic being do occur, assuredly individuals thus characterized will have the best chance of being perserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offsping similarly characterized. This principle of preservation, I have called, for the sake of brevity, Natural Selection.

I was a young man with uninformed ideas. I threw out queries, suggestions, wondering all the time over everything; and to my astonishment the ideas took like wildfire. People made a religion of them.

Hereafter we shall be compelled to acknowledge that the only distinction between species and well-marked varieties is, that the latter are known, or believed to be connected at the present day by intermediate gradations whereas species were formerly thus connected.