I’m having great trouble finding any citeable work that argues that artificial intelligence is completely impossible. People throw kiwis at AI theory in its current state, or the philosophy of functionalism, but every single argument I can find stops short of outright denunciation.

For instance, Gerald Edelman, winner of the 1972 Nobel Prize in Medicine and coiner of the term “Neural Darwinism”, argues that “AI” is impossible, expelling much hot air on the subject, but then it turns out that he believes, “It seems reasonably feasible that, in the future, once neuroscientists learn much more about consciousness and its mechanism, why not imitate it?”, and remarks “We construct what we call brain-based devices, or BBDs, which I think will be increasingly useful in understanding how the brain works and modeling the brain. But it also may be the beginning of the design of truly intelligent machines.” So that’s not very anti-AI. Edelman was also quoted in John Horgan’s recent anti-Singularity piece in IEEE Spectrum, the “Consciousness Conundrum”, in support of the idea that AI is difficult. But if he thinks AI is so difficult, why is he spending time and money on brain-based devices, which are steps towards AI?

According to his Wikipedia article, Hurbert Dreyfuss, author of “What Computers Can’t Do: the Limits of Artificial Intelligence“, argues “that we cannot know (and never will) be able to understand our own behavior in the same way as we understand objects in, for example, physics or chemistry: that is, by considering ourselves as things whose behaviour can be predicted via ‘objective’, context free scientific laws.” But then the article also states, “he doesn’t believe that AI is fundamentally impossible; only that the current research program is fatally flawed. Instead he argues that to get a device (or devices) with human-like intelligence would require them to have a human-like being in the world, which would require them to have bodies more or less like ours, and social acculturation (i.e. a society) more or less like ours.”

Very confusing, but I’m not done yet. Next comes famous physicist and Hawking-collaborator Roger Penrose and his poorly thought out theories on consciousness. Penrose argues that quantum decoherence in neural macrotubules is essential to our intelligence and consciousness. This was decisively refuted by our friend Max Tegmark in 2000, who calculated that the timescale of neuron firing and excitations in microtubules is slower than the decoherence time by a factor of at least 10,000,000,000. Still, although Penrose fusses about the alleged non-algorithmic nature of intelligence throughout his books on the topic, according to a review by Robin Hanson, “Penrose grants that we may be able to artificially construct conscious intelligence, and “such objects could succeed in actually superseding human beings.” But he thinks “algorithmic computers are doomed to subservience.” Another thinker who objects to the mainline AI philosophy and approach but doesn’t actually believe that AI will never be possible if we aren’t creative enough.

There’s more stuff out there. Paul Churchland says, “Classical AI is unlikely to yield conscious machines; systems that mimic the brain might”. More of the same. Copy a certain type of big-headed ape exactly, and intelligence will pop out, but if you try anything else, you’ll fail. Even Searle, the king of AI criticism, acknowledges that “machines with internal causal powers equivalent to those of brains” could think. I’m not sure precisely what he means by this, but by bothering to say something besides humans, even Searle seems to believe that some form of Artificial Intelligence is possible.

Where are the people saying “AI will never happen” or “only human beings can think”? I can find hundreds of references made by laypeople on various forums, but they generally don’t present coherent arguments, they just throw out their opinions.

If no philosopher, cognitive scientist, or computer scientist is willing to claim in public that true AI is impossible, then isn’t this an important finding in and of itself? If it is, then I totally get the credit.