I recently discovered an interview series by a remarkably good interviewer, Nikola Danaylov, who seems quite skilled at doing something that one hardly ever sees in media interactions with scientists: challenging the interviewee’s assumptions. Danaylov manages it without ever breaking decorum or giving offense (a skill that a good many non-science journalists could stand to learn). In this post I want to mention two interviews, partly because both are interesting and worth watching, and partly because both related to another issue that I have been thinking about. The first interview is with Dr. Stuart Hameroff, a University of Arizona professor who, in collaboration with Oxford professor Roger Penrose, is the originator of a hypothesis that (to oversimplify) consciousness arises from quantum computation taking place in the microtubules of neurons. The second interview is with Prof. Frank Tipler, a physicist and mathematician and the author of two very controversial books, The Physics of Immortality and The Physics of Christianity, expounding his “omega point cosmology” and projecting the ultimate fate of the universe.

I don’t mean to compare Hameroff’s Orch-OR theory with Tipler’s omega point theory, in terms of either subject matter or credibility. Hameroff tends to annoy some mainstream neuroscience folks — as well as many in the AI field — by rejecting the idea that ordinary Hodgkin-Huxley-type neural activity is sufficient to explain consciousness. Some may also be put off by his tendency to draw parallels with the ideas of various eastern philosophies (I recall attending a seminar of his at ASU a few years ago, presented jointly with a Tibetan Buddhist Rinpoche, which was different), but no one could credibly dismiss him as a crank — he is a professor of medicine, an anesthesiologist with decades of experience, and the driving force behind a well-regarded international conference on the study of consciousness, now in its 21st year — and his collaborator is Roger Penrose, perhaps the greatest living mathematical physicist. The weight of critical opinion tends to be considerably less kind to Tipler; he is a full professor of physics and mathematics at a major university (Tulane) and studied under no less a luminary than John Wheeler, but mixing physics and theology tends to set mainstream science’s teeth on edge. Of course, as I have carried on about elsewhere, personally I enjoy iconoclasts.

The point that I wanted to make has to do with the question of how we decide when we understand something. According to a fairly widely held point of view, consciousness is an “emergent” property that arises from computation when the computation reaches some threshold level of complexity. By that reasoning, some expect that when computers reach the point where they have computing power equivalent to a human brain, they will be conscious. Hameroff and Penrose vigorously dispute this, pointing out that no credible mechanism has been suggested by which consciousness would emerge from computation, and that proponents of this point of view cannot say what the required threshold level of complexity would be, or explain why a complexity of X would produce consciousness and a complexity of half-X would not. Hameroff also cites interesting data relating to the effects of anesthetic compounds on microtubules. The Hameroff-Penrose “Orch-OR” theory is described in detail in a recent review paper.

Tipler, in the interview linked above, makes the statement that we already have a “theory of everything” — that quantum mechanics, general relativity, and the standard model of particle physics, taken together, are a theory of everything, and that the future of the universe is entirely, deterministically, predictable from that.

So here we have two examples of assumptions of complete understanding — one in mainstream neuroscience and AI, that computation is enough to explain consciousness, and one by Tipler that the current foundations of physics are sufficient to understand all there is to say about the universe. Personally, I take strong issue with those kinds of claims, because they close off further inquiry. Once you’ve decided that you understand something, there’s no reason to keep looking for other explanations — or to approve research grants to let anyone else keep looking, or to allow other ideas into the peer-reviewed literature.

Accordingly, I propose a corollary to my previously advocated “engineerability” standard for deciding what qualifies as science: if we haven’t figured out how to engineer a thing, we don’t understand it yet. That is, if we are not able, by some deliberate action, to cause some predictable change in whatever it is through some mechanism that we can explain and control to at least some minimal extent, then we shouldn’t claim to understand it. My candidates for the top three things that humans clearly haven’t figured out how to engineer, and therefore (I would say) clearly don’t understand, are ones that encompass the subject matter of this post: consciousness, gravitation, and time.

Anyway, check out Danaylov’s interviews — they’re well worth the time.


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