Agnosticism simply means that a man shall not say he knows or believes that for which he has no grounds for professing to believe.

The world makes up for all its follies and injustices by being damnably sentimental.

Only a scientific people can survive in a scientific future.

Perhaps the most valuable result of all education is the ability to make yourself do the thing you have to do, when it ought to be done, whether you like it or not.

The great tragedy of Science - the slaying of a beautiful hypothesis by an ugly fact.

It is an error to imagine that evolution signifies a constant tendency to increased perfection. That process undoubtedly involves a constant remodelling of the organism in adaptation to new conditions; but it depends on the nature of those conditions whether the directions of the modifications effected shall be upward or downward.

Science comits suicide when it adopts a creed.

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

I have no faith, very little hope, and as much charity as I can afford.