The difference between animals and humans is that animals change themselves for the environment, but humans change the environment for themselves.

It is my eyes which see, and the sight of my eyes grants beauty to the earth. It is my ears which hear, and the hearing of my ears gives its song to the world. It is my mind which thinks, and the judgement of my mind is the only searchlight that can find the truth. It is my will which chooses, and the choice of my will is the only edict I must respect.

What is the basic, the essential, the crucial principle that differentiates freedom from slavery? It is the principle of voluntary action versus physical coercion or compulsion.

One method of destroying a concept is by diluting its meaning. Observe that by ascribing rights to the unborn, i.e., the nonliving, the anti-abortionists obliterate the rights of the living.

I think that when in doubt about the truth of an issue, it's safer and in better taste to select the least numerous of the adversaries.

Now you see, Dr. Stadler, you're speaking as if this book were addressing to a thinking audience. If it were, one would have to be concerned with such matters as accuracy, validity, logic and the prestige of science. But it isn't. It's addressed to the public.