“Religion is an illusion and it derives its strength from the fact that it falls in with our instinctual desires.”

“Religion is a system of wishful illusions together with a disavowal of reality, such as we find nowhere else but in a state of blissful hallucinatory confusion. Religion's eleventh commandment is "Thou shalt not question.”

“Perhaps the hopes I have confessed to are of an illusory nature, too. But I hold fast to one distinction. Apart from the fact that no penalty is imposed for not sharing them, my illusions are not, like religious ones, incapable of correction.”

“No, our science is no illusion. But an illusion it would be to suppose that what science cannot give us we can get elsewhere.”

“Observe the difference between your attitude to illusions and mine. You have to defend the religious illusion with all your might. If it becomes discredited - and indeed the threat to it is great enough - then your world collapses. There is nothing left for you but to despair of everything, of civilization and the future of mankind. From that bondage I am, we are, free. Since we are prepared to renounce a good part of our infantile wishes, we can bear it if a few of our expectations turn out to be illusions.”

“We believe that it is possible for scientific work to gain some knowledge about the reality of the world, by means of which we can increase out power and in accordance with which we can arrange our life. If this belief is an illusion, then we are in the same position as you. But science has given us evidence by its numerous and important successes that it is no illusion.”

“Religion is an attempt to get control over the sensory world, in which we are placed, by means of the wish-world, which we have developed inside us as a result of biological and psychological necessities. But it cannot achieve its end. Its doctrines carry with them the stamp of the times in which they originated, the ignorant childhood days of the human race. Its consolations deserve no trust. Experience teaches us that the world is not a nursery. The ethical commands, to which religion seeks to lend its weight, require some other foundations instead, for human society cannot do without them, and it is dangerous to link up obedience to them with religious belief. If one attempts to assign to religion its place in man’s evolution, it seems not so much to be a lasting acquisition, as a parallel to the neurosis which the civilized individual must pass through on his way from childhood to maturity.”