It is the first duty of a hypothesis to be intelligible.

It is not who is right, but what is right, that is of importance.

It is wrong for a man to say that he is certain of the objective truth of any proposition unless he can produce evidence which logically justifies that certainty.

Science is nothing, but trained and organized common sense.

Protoplasm, simple or nucleated, is the formal basis of all life. It is the clay of the potter: which, bake it and paint it as hewill, remains clay, separated by artifice, and not by nature from the commonest brick or sun-dried clod.

Material advancement has its share in moral and intellectual progress. Becky Sharp's acute remark that it is not difficult to be virtuous on ten thousand a year has its applications to nations; and it is futile to expect a hungry and squalid population to be anything but violent and gross.

Every living creature commences its existence under a form different from, and simpler than, that which it eventually attains.