It is not the biggest, the brightest or the best that will survive, but those who adapt the quickest.

When it was first said that the sun stood still and world turned round, the common sense of mankind declared the doctrine false; but the old saying of Vox populi, vox Dei [the voice of the people is the voice of God], as every philosopher knows, cannot be trusted in science.

On your life, underestimating the proclivities of finches is likely to lead to great internal hemorrhaging.

Of all the differences between man and the lower animals, the moral sense or conscience is by far the most important. This sense, as Mackintosh remarks, "has a rightful supremacy over every other principle of human action"; it is summed up in that short but imperious word "ought," so full of high significance. It is the most noble of all the attributes of man, leading him without a moment's hesitation to risk his life for that of a fellow-creature; or after due deliberation, impelled simply by the deep feeling of right or duty, to sacrifice it in some great cause.

In my simplicity, I remember wondering why every gentleman did not become an ornithologist.

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.

The loss of these tastes [for poetry and music] is a loss of happiness, and may possibly be injurious to the intellect, and more probably to the moral character, by enfeebling the emotional part of our nature.