"Mankind is considered (by the radical environmentalists) the lowest and the meanest of all species and is blamed for everything."
"In a state therefore of great equality and virtue, where pure and simple manners prevailed, the increase of the human species would evidently be much greater than any increase that has been hitherto known."
"The Endangered Species Act is the strongest and most effective tool we have to repair the environmental harm that is causing a species to decline."
"The struggle for existence holds as much in the intellectual as in the physical world. A theory is a species of thinking, and its right to exist is coextensive with its power of resisting extinction by its rivals."
"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."
"There is no scientific reason to think that we, even with space travel, are going to survive as a species for ever, certainly not by biting off the hand that feeds us, which is exactly what we are doing."
"There are a lot of obstacles in the way of our understanding animal intelligence - not the least being that we can't even agree whether nonhuman species are conscious. We accept that chimps and dolphins experience awareness we like to think dogs and cats do. But what about mice and newts? What about a fly? Is anything going on there at all?"
"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."
"And History will smile to think that this is the species for which Socrates and Jesus Christ died."
"It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change."