Religious reasons, which is no reason. I notice Skeptic had a review of Dennett's book, Darwin's Dangerous Idea. Religious reasons amount to what Dennett terms "skyhooks." Do you believe in skyhooks? I don't.

However, I think the major opposition to ecology has deeper roots than mere economics; ecology threatens widely held values so fundamental that they must be called religious.

Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons.

A coldly rationalist individualist can deny that he has any obligation to make sacrifices for the future.

It takes five years for a willing person's mind to change. Have patience with yourself and others when treading in an area protected by a taboo.

Thou shalt not transgress the carrying capacity

It is a mistake to think that we can control the breeding of mankind in the long run by an appeal to conscience.