On the theory of natural selection we can clearly understand the full meaning of that old canon in natural history, “Natura non facit saltum.” This canon, if we look only to the present inhabitants of the world, is not strictly correct, but if we include all those of past times, it must by my theory be strictly true.

Endless forms most beautiful and most wonderful have been, and are being evolved

Extinction has only separated groups: it has by no means made them; for if every form which has ever lived on this earth were suddenly to reappear, though it would be quite impossible to give definitions by which each group could be distinguished from other groups, as all would blend together by steps as fine as those between the finest existing varieties, nevertheless a natural classification, or at least a natural arrangement, would be possible.

Even people who aren’t geniuses can outthink the rest of mankind if they develop certain thinking habits.

Why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms.

Blushing is the most peculiar and the most human of all expressions. Monkeys redden from passion, but it would require an overwhelming amount of evidence to make us believe that any animal could blush.

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