Blockhead Intelligence

TomsGuide  |  The Blockhead thought experiment represents another serious hurdle in ascribing agency to AIs. Like solipsism, it challenges us to think about whether other entities have inner lives — and whether it matters if they do.

“The Blockhead thought experiment is this idea going back to the earliest days [of AI] when we saw that you could fool humans into thinking you were intelligent just by having a good stock of canned responses,” Buckner explained. “What if you just scaled that up indefinitely?

“Any conversation you have with one of these systems is going to be finite. There’s a finite number of things you can say to it, and a finite number of things it can say back to you. At least in principle, it could be explicitly programmed as a kind of lookup table. The same way that the kid who doesn’t really want to learn how to do long division and wants to do well on the quiz might just memorize a bunch of common answers … without ever actually learning how to do the long division process. It’s like that, but for everything.”

Most readers have probably heard of the Turing test, which cryptographer Alan Turing devised in 1950 to determine whether machines could exhibit human intelligence. Without rehashing the whole experiment here, the idea is that a human and a computer would communicate, and that a human observer would try to determine which participant was which. If the observer could not tell, then the computer would pass the test. Whether doing so proved a computer’s “intelligence” is up for debate, but the Turing test is still a useful shorthand for machines that aim to mimic human behaviors.

Ned Block, the philosopher who first proposed the Blockhead experiment (although not under that name), argued that any program with a sufficiently diverse range of responses could reliably pass the Turing test, even though doing so would not demonstrate any kind of actual intelligence. Instead, the program would essentially be an extremely intricate spreadsheet, picking the most “sensible” response based on algorithmic logic.

The idea of a program with an essentially infinite cache of stock answers was far-fetched in the early days of AI technology. But now that chatbots can essentially access the whole Internet to craft their responses, what we have sounds an awful lot like a Blockhead computer.

“The Blockhead thought experiment is meant to decisively rebut [the Turing] test as a test for intelligence,” Buckner said. “Just by having canned responses to everything preprogrammed in a lookup table. That is a real threat today with these deep learning systems. It seemed like an ‘in-principle’ threat or a thought-experiment-type threat rather than an actual engineering threat, until we had the systems that have the memory capacity to memorize huge swaths of the Internet.”

Block used this thought experiment to argue for a philosophical concept called “psychologism,” which maintains that the psychological process by which an entity synthesizes information is important. In other words, a disciple of psychologism would argue that a Blockhead computer is not intelligent, because consulting a lookup table is not the same as reasoning through a problem. (Block presented this idea in contrast to another philosophical concept called “behaviorism,” although the two are not always mutually exclusive.)

“[An AI] could have the exact same responses as a human, and yet it’s not intelligent, because it’s not generating them by intelligently processing the information,” Buckner said. “We need to actually probe what’s going on under the hood in these systems to see if they’re doing some intermediate, representational processing in the way that we would.”

Under a psychologistic approach, nothing your AI chatbot tells you is an original idea, even if it comes up with a phrase, song lyric or story concept that no one’s ever used before. With a complex enough algorithm, and a big enough source of information, it can essentially bluff its way past any query without ever applying real reason or creativity.