Tuesday, July 19, 2005

Objective versus subjective reality: Which is primary?

This post is a purely intellectual one -- playing at the border between "blog entry" and "brief philosophical essay"..... It transmits a small portion of the philosophical train of thought I undertook while wandering with Izabela at White Sands National Monument a few weeks ago. Much of that train of thought involved issues such as free will and the emergence of notions of self, will and reality in the infant's mind (the epigenesis of conceptual structures and cognitive dynamics in the infant and toddler mind is much on my mind these days, because in the Novamente AI project we're working on putting together a demonstration of Novamente progressing through the earlier of Jean Piaget's stages of child cognitive development). But what I'll discuss here today is a bit different from that: the relation between objective and subjective reality.

One of my motivations for venturing into this topic is: I've realized that it's wisest to clearly discuss the issue of reality before entering into issues of consciousness and will. Very often, when I try to discuss my theory of consciousness with people, the discussion falls apart because the people I'm talking to want to assume that objective reality is primary, or else that subjective experiential reality is primary. Whereas, to me, a prerequisite for intelligently discussing consciousness is the recognition that neither of these two perspectives on being is primary -- each has their own validity, and each gives rise to the other in a certain sense.

OK, so ... without further ado... : There are two different ways to look at the world, both of which are to some degree sympathetic to me.

One way is to view the objective world as viewed by science and society as primary, and to look at the subjective worlds of individuals as approximations to objective reality, produced by individual physical systems embedded within physical reality.

Another way is to view the subjective, experiential world of the individual world (mine, or yours) as primary, and look at "objective reality" as a cognitive crutch that the experiencing mind creates in order to make use of its own experience.

I think both of these views are valid and interesting ones -- they each serve valuable purposes. They don't contradict each other, because the universe supports "circular containment": it's fine to say "objective reality contains subjective reality, and subjective reality contains objective reality." The theory of non-well-founded sets shows that this kind of circularity is perfectly consistent in terms of logic and mathematics. (Barwise and Etchemendy's book "The Liar" gives a very nice exposition of this kind of set theory for the semi-technical reader. I also said a lot about this kind of mathematics in my 1994 book Chaotic Logic, see a messy rough draft version of the relevant chapter here ... (alas, I long ago lost the files containing the final versions of my books!!))

But it's also interesting to ask if either of the two types of world is properly viewed as primary. I'll present here an argument that it may make sense to view either subjective or objective reality as primary, depending on the level of detail with which one is trying to understand things.

My basic line of argument is as follows. Suppose we have two entities A and B, either of which can be derived from the other -- but it's a lot easier to derive B from A than to derive A from B. Then, using the principle of Occam's Razor, we may say that the derivation of B from A is preferable, is more fundamental. (For those not in the know, Occam's Razor -- the maxim of preferring the simplest explanation, from among the pool of reasonably correct ones -- is not just a pretty little heuristic, but is very close to the core of intelligent thought. For two very different, recent explorations of this theme, see Marcus Hutter's mathematical theory of general intelligence; and Eric Baum's book What is Thought (much of which I radically disagree with, but his discussion of the role of Occam's Razor in cognition is quite good, even though he for some reason doesn't cite Ray Solomonoff who conceived the Occam-cognition connection back in the 1960's)).

I will argue here that it's much easier to derive the existence of objective reality from the assumption of subjective reality, than vice versa. In this sense, I believe, it's sensible to say that the grounding of objective reality in subjective reality is primary, rather than vice versa.

On the other hand, it seems that it's probably easlier to derive the details of subjective reality from the details of objective reality than vice versa. In this sense, when operating at a high level of precision, it may be sensible to say that the grounding of subjective reality in objective reality is primary, rather than vice versa.

Suppose one begins by assuming "subjective reality" exists -- the experienced world of oneself, the sensations and thoughts and images and so forth that appear in one's mind and one's perceived world. How can we derive from this subjective reality any notion of "objective reality"?

Philip K. Dick defined objective reality as "that which doesn't go away even when you stop believing in it." This is a nice definition but I don't think it quite gets to the bottom of the matter.

Consider the example of a mirage in the desert -- a lake of water that appears in the distance, but when you walk to its apparent location, all you find is sand. This is a good example of how "objective reality" arises within subjective reality.

There is a rule, learned through experience, that large bodies of water rarely just suddenly disappear. But then, putting the perceived image of a large body of water together with the fact that large bodies rarely disappear,and the fact that when this particular large body of water was approached it was no longer there -- something's gotta give.

There are at least two hypotheses one can make to explain away this contradiction:

1. one could decide that deserts are populated by a particular type of lake that disappears when you come near it, or

2. one can decide that what one sees from a distance need not agree with what one sees and otherwise senses from close up.

The latter conclusion turns out to be a much more useful one, because it explains a lot of phenomena besides mirage lakes.

Occam's Razor pushes toward the second conclusion, because it gives a simple explanation of many different things, whereas explanations of form 1 are a lot less elegant, since according to this explanatory style, each phenomenon where different sorts of perception disagree with each other requires positing a whole new class of peculiarly-behaving entity.

Note that nothing in the mirage lake or other similar experiences causes one to doubt the veracity of one's experiences.

Each experience is valid unto itself. However, the mind generalizes from experiences, and takes particular sensations and cognitions to be elements of more general categories. For instance, it takes a particular arrangement of colors to be a momentary image of a "lake", and it takes the momentary image of a lake to be a snapshot of a persistent object called a "lake." These generalizations/categorizations are largely learned via experience, because they're statistically valid and useful for achieving subjectively important goals.

From this kind of experience, one learns that, when having a subjective experience, it's intelligent to ask "But the general categories I'm building based on this particular experience -- what will my future subjective experiences say about these categories, if I'm experiencing the same categories (e.g. the lake) through different senses, or from different positions, etc." And as soon as one starts asking questions like that -- there's "objective reality."

That's really all one needs in order to derive objective reality from subjective reality. One doesn't need to invoke a society of minds comparing their subjective worlds, nor any kind of rigorous scientific world-view. One merely needs to posit generalization beyond individual experiences to patterns representing categories of experience, and an Occam's Razor heuristic.
In the mind of the human infant, this kind of reasoning is undertaken pretty early on -- within the first six months of life.

It leads to what developmental psychologists call "object permanence" -- the recognition that, when a hand passes behind a piece of furniture and then reappears on the other side, it still existed during the interim period when it was behind the furniture. "Existed" here means, roughly, "The most compact and accurate model of my experiences implies that if I were in a
different position, I would be able to see or otherwise detect the hand while it was behind the chair, even though in actual fact I can't see or detect it there from my current position." This is analogous to what it means to believe the mirage-lake doesn't exist: "The most compact and accurate model of my experiences implies that if I were standing right where that lake
appears to be, I wouldn't be wet!" Notice from these examples how counterfactuality is critical to the emergence of objective from subjective reality. If the mind just sticks to exactly what it experiences, it will never evolve the notion of objective reality. Instead, the mind needs to be able to think "What would I experience if...." This kind of basic counterfactuality leads fairly quickly to the notion of objective reality.

On the other hand, what does one need in order to derive subjective reality from objective reality? This is a lot trickier!

Given objective reality as described by modern science, one can build up a theory of particles, atoms, molecules, chemical compounds, cells, organs (like brains) and organisms -- and then one can talk about how brains embodied in bodies embedded in societies give rise to individual subjective realities. But this is a much longer and more complicated story than the emergence of objective reality from subjective reality.

Occam's-razor-wise, then, "objective reality emerges from subjective reality" is a much simpler story than the reverse.

But of course, this analysis only scratches the surface. The simple, development-psychology approach I've described above doesn't explain the details of objective reality -- it doesn't explain why there are the particular elementary particles and force constants there are, for example. It just explains why objective reality should exist at all.

And this point gives rise to an interesting asymmetry. While it's easier to explain the existence of objective reality based on subjective reality than vice versa, it seems like it's probably easier to explain the details of subjective reality based on objective reality than vice versa. Of course, this is largely speculative, since right now we don't know how to do either -- we can't explain particle physics based on subjectivist developmental psychology, but nor can we explain the nature of conscious experience based on brain function. However, my intuition is that the latter is an easier task, and will be achieved sooner.

So we then arrive at the conclusion that:

  • At a coarse level of precision, "subjectivity spawns objectivity" is a simpler story than vice versa
  • At a higher level of precision, "objectivity spawns subjectivity" is a simpler story than vice versa

So, which direction of creation is more fundamental depends on how much detail one is looking for!

This is not really such a deep point -- but it's a point that seems to elude most philosophers, who seem to be stuck either in an "objective reality is primary" or "subjective reality is primary" world-view. It seems to me that recognizing the mutual generation of these two sorts of reality is prerequisite for seriously discussing a whole host of issues, including consciousness and free will. In my prior writings on consciousness and will I have taken for granted this kind of mutual-generationist approach to subjectivity/objectivity, but I haven't laid it out explicitly enough.

All these issues will be dealt with in my philosophy-of-mind book "The Hidden Pattern", which I expect to complete mid-fall. I wish I had more time to work on it: this sort of thinking is really a lot of fun. And I think it's also scientifically valuable -- because, for example, I think one of the main reasons the field of AI has made so little progress is that the leading schools of thought in academic and industrial AI all fall prey to fairly basic errors in the philosophy of mind (such as misunderstanding the relation between objective and subjective reality). The correct philosophy of mind is fairly simple, in my view -- but the errors people have made have been quite complicated in some cases! But that's a topic for future blog entries, books, conversations, primal screams, whatever....

More later ... it's 2AM and a warm bed beckons ... with a warm wife in it ;-> ... (hmm -- why this sudden emphasis on warmth? I think someone must have jacked the air conditioning up way too high!!)