... two men could be just alike in all their dispositions to verbal behavior under all possible sensory stimulations, and yet themeanings or ideas expressed in their identically triggered and identically sounding utterances could diverge radically, for the two men, in a wide range of cases.

Physics investigates the essential nature of the world, and biology describes a local bump. Psychology, human psychology, describes a bump on the bump.

Unscientific man is beset by a deplorable desire to have been right. The scientist is distinguished by a desire to be right.

One man's observation is another man's closed book or flight of fancy.

It is one of the consolations of philosophy that the benefit of showing how to dispense with a concept does not hinge on dispensing with it.

Creatures inveterately wrong in their inductions have a pathetic but praise-worthy tendency to die before reproducing their kind.

Theory may be deliberate, as in a chapter on chemistry, or it may be second nature, as in the immemorial doctrine of ordinary enduring middle-sized physical objects.