Nature is indifferent to the survival of the human species including Americans.

A strong body makes the mind strong. As to the species of exercises I advise the gun. While this gives moderate exercise to the body it gives boldness enterprise and independence to the mind. Games played with the ball and others of that nature are too violent for the body and stamp no character on the mind. Let your gun therefore be your constant companion of your walks.

In June as many as a dozen species may burst their buds on a single day. No man can heed all of these anniversaries no man can ignore all of them.

Men and women belong to different species and communications between them is still in its infancy.

Love is only a dirty trick played on us to achieve continuation of the species.

A man reserves his true and deepest love not for the species of woman in whose company he finds himself electrified and enkindled but for that one in whose company he may feel tenderly drowsy.

As a species we are always hungry for new knowledge.

I absolutely don't think a sentient artificial intelligence is going to wage war against the human species.

The question that will decide our destiny is not whether we shall expand into space. It is: shall we be one species or a million? A million species will not exhaust the ecological niches that are awaiting the arrival of intelligence.

I think it's realistic to have hope. One can be a perverse idealist and say the easiest thing: 'I despair. The world's no good.' That's a perverse idealist. It's practical to hope because the hope is for us to survive as a human species. That's very realistic.