Going Loopy Over Consciousness

By David Deutsch
Physics World
July 2, 2007

Edited by Andy Ross

I Am a Strange Loop
Douglas Hofstadter
Basic Books, 412 pages

Douglas Hofstadter, a professor of cognitive science at Indiana University, expresses disappointment that his 1979 masterpiece Gödel, Escher, Bach (one of my favourite books) was not recognized as explaining the true nature of consciousness, or "I"-ness. I have to confess that it never occurred to me that it was intended to do so.

This is a nice line but it is a trifle disingenuous. It seemed clear to me that Hofstadter did nurse some such ambition, even though the word "consciousness" was not then bandied about so freely as it has been in the last decade.

I Am a Strange Loop is supposed to restate and explain his solution: in short, that a mind is a near-infinitely extendable, self-referential loop of symbols that suffers – or rather, benefits – from the hallucination of being an "I". Furthermore (Hofstadter says paradoxically), that hallucination is itself an "I".

Here one might reasonably accuse Hofstadter of being excessively cute with the word "hallucination". Can one hallucinate a hallucination? Or does one, rather, have a hallucination, or hallucinate a vision or a face or a self?

Strangely, Hofstadter's half of this theory of consciousness (the loopy half), is quite convincing. The unconvincing half is essentially philosopher Daniel Dennett's theory from his book Consciousness Explained (which critics have justly renamed Consciousness Denied) – namely that our opinion that we are conscious is simply mistaken.

This is unfair on Dan, whose critics have lambasted his hubris with excessive gusto. Dennett made it quite clear that what we are mistaken about is the physical or other nature of consciousness, not that the word denotes a quite unexceptional denizen of the curiously nebulous bestiary our folk psychology. For Dan, consciousness is at least as real as ectoplasm or sweet dreams.

The central analogy is between minds and other "strange loops": certain self-referential statements discovered by Kurt Gödel within formal mathematical systems. These statements assert their own unprovability within the system but are nevertheless provably true, akin to the paradoxical "this statement is false".

I first read GEB some five years after writing a well regarded thesis on Gödel's results, so I was optimally primed to absorb and evaluate its message. I was persuaded. The logic is as sound as, given its loopiness, it can be. I agree with Hofstadter that Gödel not only torpedoed the mighty flagship of Russell and Whitehead's ramified theory of types but also gave us a defining metaphor for a new view of logic.

Hofstadter imagines a computer made of toppling dominoes that is designed to factorize integers. It is presented with the input "641" and set in motion to perform its computation. Why is one particular domino left standing? The most fundamental explanation does not refer to the sequence in which the other dominoes fell; rather it is "because 641 is prime".

This is a great example, but unfortunately it invites extrapolation to wild excess. The claim that 641 is prime is a typical truth about Platonic heaven. Roger Penrose and many others have waxed lyrical enough about this heaven to make its attractions quite undeniable, at least to those of a certain psychological disposition. But another truth about the realm of concepts, analogous to truths about Hamlet or unicorns, is the claim that God is perfect. Deutsch would appear to agree that the "most fundamental explanation" of the manifest glory of creation is that God is perfect! Reductio ad absurdum, I trust.

Hofstadter's claim that our nature prevents us from understanding our nature cannot be taken at face value. Like a Gödelian claim to be unprovable, it applies only inside the system from which it is derived, namely Hofstadter's own philosophical framework. But, again like Gödel's construction, this simultaneously reveals that there is a truth to be discovered outside of that framework.

Sorry, David, but yes it can. You are right that it applies only inside the system and so on, but think for a second. There is no framework that I can appeal to outside of my "I" since the very act of invoking it brings it inside my I-horizon. Of course, you can be outside my horizon and vice versa, but we are both stuck inside our own horizons. Dennett tried to sneak around this circularity with his talk of autophenomenology and heterophenomenology, which breaks out of any particular loop, but "my" loop always remains, even as "I" drift toward solipsism.

Something new is needed to discover that truth, and Hofstadter's loops are probably involved. "Strange loopiness" is a distinctive form of emergence, rooted not in complexity but in universality, the real substrate of "I"-ness.

Yes, I agree that the loop story is a decisive step forward on all this. We have a logical paradigm that gives us a technical hold on something that is otherwise too slippery to work with. We can program robots to loop their self-images indefinitely, and if they are smart enough and so on, that should do the trick.

David Deutsch is at the Centre for Quantum Computation, University of Oxford, UK, and is the author of The Fabric of Reality

The Ross verdict: Read my blips.