What a distressing contrast there is between the radiant intelligence of the child and the feeble mentality of the average adult.

Only the real, rare, true scientific minds can endure doubt, which is attached to all our knowledge.

I had thought about cocaine in a kind of day-dream.

America is a mistake, a giant mistake.

Children are completely egoistic; they feel their needs intensely and strive ruthlessly to satisfy them.

Just as a satisfaction of instinct spells happiness for us, so severe suffering is caused us if the external world lets us starve, if it refuses to sate our needs. One may therefore hope to be freed from a part of one's sufferings by influencing the instinctual impulses.

Religious doctrines … are all illusions, they do not admit of proof, and no one can be compelled to consider them as true or to believe in them.