The most powerful factors in the world are clear ideas in the minds of energetic men of good will.

- J. Arthur Thomson

There is no counting the unsolved problems of Natural History.

- J. Arthur Thomson

The chief end of science is to make things clear, the educative aim is to foster the inquisitive spirit.

- J. Arthur Thomson

The man who has grit enough to bring about the afforestation or the irrigation of a country is not less worthy of honor than its conqueror.

- J. Arthur Thomson

Was it not the great philosopher and mathematician Leibnitz who said that the more knowledge advances the more it becomes possible to condense it int…

- J. Arthur Thomson

The Doctrine of Evolution states the fact that the present is the child of the past and the parent of the future.

- J. Arthur Thomson

A prolonged war in which a nation takes part is bound to impoverish the breed, since the character of the breed depends on the men who are left.

- J. Arthur Thomson

All Nature bristles with the marks of interrogation-among the grass and the petals of flowers, amidst the feathers of birds and the hairs of mammals,…

- J. Arthur Thomson