I Am a Strange Loop

The well-known Australian philosopher of mind David Chalmers, which not only is a cherished friend but also is my former doctoral student, has devoted many years to arguing for the provocative idea that there could be both “machines that think” and also “machines who think”. For me, the notion of both types of machine coexisting makes no sense, because, as I declared in Chapter 19, the word “thinking” stands for the dancing of symbols in a cranium or careenium (or some such arena), and this is also what is denoted by the word “consciousness”. Since being conscious merits the use of the pronoun “who” (and also, of course, the pronouns “I”, “me”, and so on), so does thinking — and that settles the question for me. In other words, “machine that thinks” is an incoherent phrase because of its relative pronoun, and if some day there really are machines that think, then by definition they will be machines who think.

Two Machines

Dave Chalmers explores these issues in an unprecedented new fashion. He paints a picture of a world that has two machines identical down to the last nail, transistor, atom, and quark, and these two machines, sitting side by side on an old oaken table in Room 641 of the Center for Research into Consciousness and Cognetics at Pakistania University, are carrying out exactly the same task. For concreteness’ sake, let’s say both machines are struggling to prove, using informal geometrical insights rather than formal algebraic manipulations, the simple but surprising “chord–angle theorem” of Euclidean geometry, which states that if a point (A in the figure below) moves along an arc of a circle, then the angle (α) subtended by a fixed chord (BC) that the point is “looking at” as it moves along will be constant.

I chose this elementary but elegant theorem because it is one that Dave and I discussed together with great pleasure many years ago, and some of his comments on it gave me insights that literally changed my life. In fact, that fateful fork in the road way back when allows me to imagine Switch #6, the throwing of which would subtract from my brain all knowledge of this theorem and all the subsequent passion for geometry that was sparked by my thinking carefully about it…

As I was saying, these two exactly identical machines are launched on this task in the exact same terasecond by an atomic clock, and they proceed in exact lockstep synchrony towards its solution, simulating, let us say, the exact processes that took place in Dave Chalmers’ own brain when he first found an insight-yielding visual proof. The details of the program running in both machines are of no import to us here; what does matter is that Machine Q (it stands for “qualia”) is actually feeling something, whereas Machine Z (it rhymes with “dead”) is feeling nothing. This is where Dave’s ideas grow incomprehensible to me.

Now I have to admit that in order to make it a bit easier to envision, I have slightly altered the story that Dave tells. I placed these two machines side by side on the old oaken table in Room 641 of CRCC, while Dave never does that. In fact, he would protest, saying something such as, “It’s bloody incoherent to postulate two identical machines running identical processes on the very same oaken table with one of them feeling something and the other one not. That violates the laws of the universe!”

I fully accept this objection and plead guilty to having distorted Dave’s tale. To atone for my sin and to turn my story back into his, I first remove one of the machines from the old oaken table in Room 641. Let’s call the machine who remains, no matter what we’d called it before, “Machine Q”. Now (following Dave), we take a rather unexpected step: we imagine a different but isomorphic (i.e., “separate but indistinguishable”) universe. We’ll call the first one “Universe Q” and the new one “Universe Z”. Both universes have exactly the same laws of physics, and in each universe the laws of physics are all one needs to know in order to predict what will happen, given any initial configuration of particles.

When I say these two universes are indistinguishable, one of the myriad consequences is that Universe Z, just like Universe Q , has a Milky Way galaxy, a star therein called “Sol” with a nine-planet solar system whose third planet is called “Earth”, and on Universe Z’s Earth there is a Pakistania University with a Center for Research into Consciousness and Cognetics, and in it, good old Room 641. There is even “the same” old oaken table, and there, lo and behold, is “the same machine” sitting on it. Surely you see it, do you not? But since this machine is in Universe Z, we will call it “Machine Z”, just so that we have different names for these indistinguishable machines located in indistinguishable surroundings.