PSYCHOLOGY NOT NEEDED FOR LOGIC, RUSSELL DECLARES

Bertrand Russell last night held for an hour the attention of an audience which packed the New Lecture Hall to standing capacity as he expounded his view that "logic can be studied entirely without attention to psychology, since you can know that two propositions have the same meaning without knowing what that meaning is; but that, if meaning be analyzed, it will probably find its definition lying in the field of behavioristic psychology."

The speaker stressed that the three fields, logic, psychology, and epistemology must be kept distinct. He was introduced, and his lecture was amusingly epitomized by Professor A. N. Whitehead, who termed the greatest of the missing Platonic dialogues the "Dialogue of Bertrand Russell."

"The logician is interested not in what symbols mean, but in how they mean," Mr. Russell said. "Though there may be universes in which it is possible, we cannot justify inductive logic. And deductive logic depends on symbols having meaning."

Meaning is Vague

"If the word 'Caesar' is said to mean Caesar, this involves the assumption of much historical knowledge. It might be possible to trace back the noises which the Romans made when thew saw the conqueror coming, and which were used in acclamation of the emperor by the Roman mobs. Though the whole concept of meaning is vague, the meaning of a word lies largely in its ability to produce an effect, as when we call someone by name.

"The word 'stone' can never have the affect of the object. To say, 'I shall pull your nose' may be as effective in producing anger as to carry out the threat. A man's mouth waters when he first eats a lemon, then when he sees another eating it, then when he hears the word 'lemon'. When this occurs he has learned the meaning of the word. It is astonishing (with references to Pawlow,) how much you can tell by watching a dog's mouth water. I certainly think this idea of the conditioned reflex largely covers the question of meaning.

Conditioned Reflexes

"It would be hard to say what the reflex to some abstract word such as 'incompatibility' would be. Yet here again I think conditioned reflexes would be involved. Meaning is therefore a psychological, or a physiological concept."

Mr. Russell defined psychology as "that matter which is treated in books called psychology books."

"I think brain and mind are both abstractions, and that the reality underlying them both is the same. They can be viewed in one way or another."

"Meaning is connected with psychology in its vagueness. Even 'cat' is not precise, for at some time in evolution there were animals not quite 'cats.' At one instant it would have been difficult to say whether Napoleon was alive or dead, though when he was alive he took care to make people aware of the fact.

"The abstract words of logical propositions are more free of vagueness, perhaps in virtue of having no meaning at all. You can keep logic pure by keeping it in a world by itself. It is when you start to apply it that you run into trouble. Logic is concerned with a transformation of symbols, not with how people think."

Either True or False

"We can be unduly psychological in our interpretation of logic. I do not agree with the notion that a proposition may be neither true or false. Though I could not prove that the largest number conceivable is divisible by three, this is either true or false.

"I do think there are facts we don't know and that propositions are true or false. The cat may be stealing the fish whether I catch her in the larder or not. The propositions of mathematics are not invented, but discovered as America was discovered."

Psychology not Needed

"Truth and falsehood, however, are not part of the subject matter of logic. It can be studied without attention to psychology."

"Few speakers could have held the attention of such an audience for an hour on such a discourse," Professor Whitehead remarked in an expression of appreciation. "The speaker is a thinker without a living peer."

Mr. Russell's former instructor had an effective last word. "I see now what Socrates would have said, as he drew his cloak about him, in the conclusion of the missing dialogue; 'I understand now, my dear Bertrand, the meaning of meaning is that my mouth is watering.