"A universe with a God would look quite different from a universe without one. A physics, a biology where there is a God is bound to look different."
Richard Dawkins
"The objections to religion are of two sorts - intellectual and moral. The intellectual objection is that there is no reason to suppose any religion true; the moral objection is that religious precepts date from a time when men were more cruel than they are and therefore tend to perpetuate inhumanities which the moral conscience of the age would otherwise outgrow."
Bertrand Russell
"A man's ethical behavior should be based effectually on sympathy, education, and social ties; no religious basis is necessary. Man would indeed be in a poor way if he had to be restrained by fear of punishment and hope of reward after death."
Albert Einstein
"Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful."
Seneca the Younger
"The position I have always adopted is that much of animal nature is indeed altruistic, cooperative and even attended by benevolent subjective emotions, but that this follows from, rather than contradicts, selfishness at the genetic level."