The time has come when scientific truth must cease to be the property of the few, when it must be woven into the common life of the world.

In-depth studies have an influence on general ideas, whereas theories, in turn, in order to maintain themselves, push their spectators to search for new evidence. The mind's activity that is maintained by the debates about these works, is probably the source of the greatest joys given to man to experience on Earth.

Every great scientific truth goes through three states: first, people say it conflicts with the Bible; next, they say it has been discovered before; lastly, they say they always believed it.

Facts are stupid until brought into connection with some general law.

The possibilities of existence run so deeply into the extravagant that there is scarcely any conception too extraordinary for Nature to realise.

But unless some great revolution in nature modifies the present relative level between land and sea, it may safely be maintained that the present outer reef is the final southern boundary of the North American continent.

The eye of the trilobite tells us that the sun shone on the old beach where he lived; for there is nothing in nature without a purpose, and when so complicated an organ was made to receive the light, there must have been light to enter it.