Milinda’s Questions

Note: This is an edited repost of a post on my predecessor blog. Original date: February 9, 2005. Remarks in italics are editorial comments added at time of reposting.

My pal Roger responded to an earlier post on David Chalmers (which I’ll try to repost also) with a question:

I wonder — where does he stand on other species. Like mice and gorillas. Are their consciousnesses epistemically and ontologically autonomous too?

I had to go look up the answer, but here’s a relevant passage, from pp. 294-5 of Chalmers’ The Conscious Mind:

[W]e can think about what might happen to experience as we move down the scale of complexity. We start with the familiar cases of humans, in which very complex information-processing gives rise to our familiar complex experiences.

Moving to less complex systems, there does not seem to be much reason to doubt that dogs are conscious, or even that mice are. Some people have questioned this, but I think this is often due to a conflation of phenomenal consciousness and self-consciousness. Mice may not have much of a sense of self, and may not be given to introspection, but it seems entirely plausible that there is something it is like to be a mouse. Mice perceive their environment via patterns of information flow not unlike those in our own brains, though considerably less complex. The natural hypothesis is that corresponding to the mouse’s “perceptual manifold,” which we know they have, there is a “phenomenal manifold.” The mouse’s perceptual manifold is quite rich — a mouse can make many perceptual distinctions — so its phenomenal manifold might also be quite rich. For example, it is plausible that for each distinction that the mouse’s visual system can make and use in perceiving the environment, there corresponds a phenomenal distinction. One cannot prove that this is the case, but it seems to be the most natural way to think about the phenomenology of a mouse.

Moving down the scale through lizards and fish to slugs, similar considerations apply.
There does not seem to be much reason to suppose that phenomenology should wink out while a reasonably complex perceptual psychology persists. If it does, then either there is a radical discontinuity from complex experiences to none at all, or somewhere along the line phenomenology begins to fall out of synchrony with perception, so that for a while, there is a relatively rich perceptual manifold accompanied by a much more impoverished phenomenal manifold. The first hypothesis seems unlikely, and the second suggests that the intermediate systems would have inner lives strangely dissociated from their cognitive capacities. The alternative is surely at least as plausible. Presumably it is much less interesting to be a fish than to be a human, with a simpler phenomenology corresponding to its simpler psychology, but it seems reasonable enough that there is something there.

As we move along the scale from fish and slugs through simple neural networks . . . , where should consciousness wink out? The phenomenology of fish and slugs will likely not be primitive but relatively complex, reflecting the various distinctions they can make. Before phenomenology winks out altogether, we presumably will get to some sort of maximally simple phenomenology.

All of which seems reasonable enough; but the reader as adept at the hermeneutics of suspicion as Roger is might be given qualms by those three little dots in the final paragraph. What’s been elided here? Well, actually, the words that occur in that space in the original text are:

. . . all the way down to thermostats . . .

And this entire discussion is found in a section of the book with the subtitle What is it like to be a thermostat? And another confession about my tampering with the text: that bracketed W at the beginning does in fact indicate that I have performed another elision. Chalmers’ original sentence reads:

To make the view seem less crazy, we can think about what might happen to experience . . .

Well. Yes. Why don’t I just let the man speak for himself? The following paragraphs appear in the book immediately before the passage I first quoted:

To focus the picture, let us consider an information-processing system that is almost maximally simple: a thermostat. Considered as an information-processing device, a thermostat has just three information states (one state leads to cooling, another to heating, and another to no action). So the claim is that to each of these information states, there corresponds a phenomenal state. These three phenomenal states will all be different, and changing the information state will change the phenomenal state. We might ask: What is the character of these phenomenal states? That is, what is it like to be a thermostat?

Certainly, it will not be very interesting to be a thermostat. The information processing is so simple that we should expect the corresponding phenomenal states to be equally simple. There will be three primitively different phenomenal states, with no further structure. Perhaps we can think of these states by analogy to our experiences of black, white, and gray: a thermostat can have an all-black phenomenal field, an all-white field, or an all-grey field. But even this is to impute far to much structure to the thermostat’s experiences, by suggesting the dimensionality of a visual field, and the relatively rich natures of black, white, and gray. We should really expect something much simpler, for which there is no analog in our experience. We will likely be unable to sympathetically imagine these experiences any better than a blind person can imagine sight, or than a human can imagine what it is like to be a bat; but we can at least intellectually know something about their basic structure.

Because it’s easier than thinking, Let me close this post with my own brief gui!de to the burgeoning online literature on Thermostat Consciousness:

– Chalmers’ paper “What is it like to be a thermostat?” Not the same as the book section with the same title, and the content is sufficiently different to be worth taking a look at.

– An exchange between Chalmers and John Searle in the New York Review of Books, in which Searle ridicules, and Chalmers defends, the notion of thermostat consciousness.

– An undergraduate term paper on the question.