Logical behaviorism tries to solve the problem of other minds by showing that behavior is the effect of mind states. By examining behavior closely enough, says the logical behaviorist, it is possible to know mental states of others … In his article “Brains and Behavior” Hilary Putnam attacks the school of thought known as logical behaviorism … Putnam believes that the basic premises of even a weakened form of logical behaviorism can be proven to be false …


This is a Philosophy paper written on November 12, 1992.

Once upon a time there was a philosophy student who was asked to explain some of the aspects of Hilary Putnam’s views on logical behaviorism and one of his thought experiments. “What a masterpiece of confusion!” he explained. “How can I ever hope to understand, much less explain, such a confusing topic?” It seemed like a supertask to the lowly student, but his will was strong and his heart was pure. Here is his work.

In his article “Brains and Behavior” Hilary Putnam attacks the school of thought known as logical behaviorism. It is, according to Putnam, a mistake. Putnam believes that the basic premises of even a weakened form of logical behaviorism can be proven to be false. Through an ingenious thought experiment and equally ingenious replies to possible objections, he proves that logical behaviorism must be abandoned.

Logical behaviorism tries to solve the problem of other minds.

Logical behaviorism tries to solve the problem of other minds by showing that behavior is the effect of mind states. By examining behavior closely enough, says the logical behaviorist, it is possible to know mental states of others. The main thesis of logical behaviorism rests on the beliefs that:

  1. there are analytic entailments between mind-statements and behavior statements and
  2. the only reason that these entailments are not translatable is because talk about the mind is more ambiguous, and therefore less specific, than talk about behavior.

It is clear that Putnam believes the answer to the problem of other minds is not logical behaviorism. The second premise he tackles first. He refutes it concisely by proving that even if there did exist analytic entailments between mind-statements and behavior-statements, there would be no possible way to translate behavior-statements into comprehensible mind-statements. He said that the lack of translations was not because of the greater ambiguity of mind-statements but instead because of the fact that causes can never be logical constructions out of effects.

The first premise was harder to prove false, but Putnam did. He proposed a thought experiment dealing with a race of people who exhibited no pain behavior but nevertheless felt pain. These super super spartans, he claimed, would refute the logical behaviorists’ belief that there are always behavior-statements which are entailments of mind states. If Putnam could prove that his X-worlders did indeed feel pain even though they didn’t express it, the first of logical behaviorism’s premises would be refuted.

Logical behaviorists, of course, would not agree with Putnam’s thought experiment. Their main objection, predicted Putnam, would be that his thought experiment is untestable and therefore, according to the verification principle, nonsense. Putnam feels that the verification principle is where the nonsense can be found. He argues however that even if the verification principle is valid, his argument is testable regardless and would not be harmed by it. This is why Putnam claims that his hypothesis, that it would be possible to be in a mental state and not display any of the normally expected unconditioned pain responses, is in principle testable. A testable hypothesis which refutes logical behaviorism is the best device to support his rejection of logical behaviorism.

Since Putnam’s X-worlders (the super super spartans) do not display or even talk about pain, he is forced to find an alternative way of proving that they are in fact (at least sometimes) in pain, in order to claim that his hypothesis is testable. For if there was no way to tell the difference between an X-worlder and a person who was simply not in pain, there would be no meaning to the thought experiment. Now that Putnam has stretched our imagination enough so that we are able to hypothesize a community of people who never exhibit pain responses, he asks us to humor him a bit more. What if, he imagines, in the far future we discover that there are waves emanating from human brains? These V-waves, as he calls them, can be decoded directly and simply into English and, amazingly, they are perfectly correlated with unspoken thoughts. We then discover that the X-worlders are emanating V-waves too, and that they are also revealing the X-worlders unspoken thoughts. And of course, they also show that the X-worlders sometimes feel pain.

Putnam raises, and replies to, possible objections before they can be made. He dispatches each one swiftly and surely and leaves us believing that his thought experiment is testable and logical behaviorism is meaningless. It is interesting, I think, that in order to make his thought experiment verifiable Putnam requires that, albeit through the use of fictitious V-waves, we have knowledge of other minds. It seems that if we ever do discover Putnam’s V-waves we will have solved the problem of other minds! Of course the new question arises, “Is the proof of others’ thoughts alone enough to prove the existence of others’ minds?”

Unfortunately it is doubtful that we will ever discover any V-waves coming from our brains, and so we are left wondering where to go from here. We cannot, if we believe Putnam, follow logical behaviorism. I think he has placed us back in our original Cartesian-esque position:

  • Facts about other minds are logically independent of behavior.
  • All we have to go on in forming beliefs about other minds is behavior.

Are these premises flawed? Will we find a solution to the problem of other minds? It is not clear from “Brains and Behavior” whether Putnam believes that there is an answer to the problem of other minds. He doesn’t give us, at least not in “Brains and Behavior”, any new paths to follow, but at least he has apparently stopped us from traveling a dead end.