What is Naturalism, Part IV: Science as a Pathway to the Noumenal

For this post I want to focus on the idea, embraced by many (implicitly if not explicitly) that contrary to what Kant thought, the noumenal realm can be reached through the scientific method—that is, through the method of (a) making careful empirical observations, often with the aid of technological enhancements that refine our capacity to observe and measure, (b) discovering recurring patterns in what is observed, and (c) constructing models (either mechanistic or mathematical) for making sense of these patterns—models which typically (but not always) are empirically testable because they make a difference with respect to what we might observe.
The idea here--which I take to be a particularly helpful way of understanding the core thesis of metaphysical naturalism--is that were this method rigorously pursued to its completion (which will never in fact be achieved), what would be uncovered is reality as it is in itself: the noumenal realm.

Now there are two things I can think of that speak in favor of this view. The first can be highlighted with an example I used in my book for a very different purpose. Years ago I was at a conference on categories in which the audience was presented with a series of computer-generated sounds. What we heard sounded like five P’s followed by five B’s. It was then explained to us that the difference between a P and a B is the interval of time between the “pop” of the lips and the onset of vocalization, and that the computer had generated ten distinct sounds by narrowing this interval by the same increment ten successive times. But because we were all English speakers, and because the English language only has two phonemes into which to categorize this range of sounds, we heard only two sounds, each repeated five times.

What does this have to do with science and bridging the gap between phenomena and noumena? Well, it seems as if, with the help of instruments that don’t have our distinct perceptual limitations, we’ve been able to isolate something in our perceptual apparatus that informs what we experience while at the same time “seeing past” that feature of our perceptual apparatus to get a truer understanding of what is going on. Sounds are more diverse and varied than what we hear, but with the right sort of technological help we can track these variations that our unaided senses can’t track. And so, it seems, we are moving towards a more accurate picture of how things are--that is, bridging or at least narrowing the phenomenal/noumenal gap.

The second point I want to make is broader. Specifically, the world as described by scientists is very different from what we immediately apprehend in our waking lives. The world of ordinary experience would have it that the desk in front of me is solid—but science has taught us that it is “really” mostly empty space, within which atoms comprised of protons and neutrons and clouds of electrons exert forces on one another. Science has taught us that the appearance of solidity is a function of how our sensory apparatuses interact with this reality—and these sensory apparatuses can themselves be studied scientifically, so as to explain why these perceptions are produced despite their disconnect with reality.

In short, science has given us a picture of the world that is very different from ordinary experience, and has at the same time given us a picture of how our senses operate—and these pictures in turn offer at least a partial account of why things appear to us as they do. It’s almost as if science has offered us a way to isolate what we bring to phenomenal experience and separate it out from what is independent of phenomenal experience. Science tells us, “The table looks solid, but we now know that it’s really mostly empty space.” This sounds like an appearance/reality distinction right in line with Kant—but more significantly, it sounds as if what science has done is taken us past appearances to the underlying reality. And so it is concluded that science has given us a glimpse of a noumenal reality that ordinary perception cannot offer.

But none of this is what one would call a deductively valid argument for the conclusion that science puts us in touch with noumenal reality. It is, rather, an interpretation of what science has done—an interpretation based on the fact that science has offered a picture of things quite different from the way things ordinarily appear to us, along with some explanations of how our minds might be structured so as to produce these appearances on the basis of an underlying reality that is as scientists have described it to be.

To see why none of this amounts to a demonstration of the fact that the scientific method is putting us in touch with noumenal reality, let me draw on something else that I use in my book for a different purpose—namely, the Matrix-like analogy of the world of brains-in-vats being fed stimuli by a supercomputer, one which also adjusts the stimuli it sends based on messages coming from the brains-in-vats. The result is a perfectly realized virtual world in which the brains-in-vats experience and respond to their environment.

For Kant, phenomenal reality is analogous to the virtual world experienced by the brains-in-vats. Noumenal reality is analogous to the brains, vats, supercomputer and its programming, etc. If we assume that the virtual world is experientially just like our own, then we can assume that the phenomena experienced by the brains-in-vats can be scientifically modeled in exactly the same ways that we model our phenomenal experience--and that the scientists of the virtual world will therefore conclude, just like we do, that tabletops that appear to be solid "are  really mostly empty space, etc."

But in our analogous case, this scientific picture of things is no more noumenal than the naïve picture. The brains studied by the scientists are phenomenal ones--not the "real ones" wired into the supercomputer, but the virtual brains produced by the supercomputer's stimuli. The sense organs studied by these scientists are likewise utterly unlike the ultimate reality (in which there are no analogous sense organs at all).  The structure and operation of these virtual brains and sense organs exist exclusively in the virtual (phenomenal) world,  and what a careful study of them tells us (about, for example, how these organs affect our perception) is also something that is true only of the phenomenal realm.

In short, the scientific models proposed to make sense of regularities in the phenomenal world are simply a way to describe (from a different angle and in minute detail) the workings of the phenomenal world. None of this gets us out of the virtual matrix and to the underlying reality. Scientists can work for centuries and never uncover the brains-in-vats or the supercomputer.

Now I don’t introduce this analogy because I think we live in a virtual reality matrix created by a supercomputer, but rather to offer an analogy that can help explain why Kant would say that the scientific picture of things is just as much phenomenal as our naïve picture of things. It’s a more helpful picture of the phenomenal world, offering us more detail and precision and incorporating an understanding of how the phenomenal self (the self as an object of experience that can be studied) interacts with other phenomenal objects to produce “second-order phenomena.” But noumenal reality is just as out of reach after science has done this work than ever before. The scientific picture is still just a picture, a way that things appear to us--and the question of how closely appearances track reality remains an open question.

Let me come at this idea from a very different angle—specifically, from an introspective one. Consciousness has a shape to it. Among other things, there is a subjective pole and an objective one—there is that which experiences and then there is that which is experienced. There’s also the matter of how we experiences, and this connects to another feature of our introspective sense of ourselves. In addition to being subjects of experience, we also seem to be agents. That is, we will things to happen which we can then observe happening.

And the center of our agency seems to be located in the same “place,” so to speak, as the subject of consciousness. It’s as if there is this “self” that is capable of both receptivity and activity—capable both of receiving something from the outside world in the form of conscious awareness, and of deciding to engage the world in various ways (by deciding what to look at, what to ignore, what to delight in and what to despise, as well as deciding how to move one’s body and the like).

Now there is a kind of activity we can pursue—an activity called objective observation—that is really about turning our attention to what we find at the objective pole of experience—the “phenomena”—and then study them in an unbiased way so as to accurately and with great precision and detail describe what we actually find there at the objective pole of experience (as opposed, say, to describing what we wish were there).

The aim is to get an “objective” understanding of what we observe, that is, an undistorted picture of what lies at the objective pole of consciousness—by which we mean a picture that hasn’t been distorted by other things that are at work in our consciousness, especially such things as desires and hopes and aversions and fears. Of course, insofar as we receive the object through our senses and in terms of our concepts and categories of understanding, what we find at the objective pole of consciousness is not the “thing in itself” but the thing as mediated by these faculties. In that sense, then, there is no such thing as an undistorted object of consciousness. Every object of experience comes to us in a form shaped by our means of apprehension and suited to our modes of cognition.

But still, there are influences on how we characterize what is on the objective pole of consciousness that aren’t part of the fixed laws by which our minds present and conceptualize experience. And these variable influences are likely to be numerous. We are rarely merely passive in relation to phenomena. We engage and interact with them. We make value judgments about them. We have feelings about them. We hope they will be like this. We are afraid the will be like that. We hate what they seem to be like. We love what we find there and don’t want it to change.

But at some point in human history it was discovered that there is something to be gained by suppressing all of this interactive engagement with phenomena and trying, instead, just to observe them--that is, to be wholly receptive in relation to them, so that we can come to discern what is there at the objective pole of consciousness with a degree of detail and accuracy that wouldn't otherwise be possible. Put another way, there is something to be gained from really paying attention to what sits at the point of interface between the conscious self and to "other."

Of course, what we gain from this receptive attention has to do with our active side: if we interact with things based on beliefs about them derived from such pure observation, the results are more predictable (things behave and respond the way we expect them to) and hence generally more rewarding. Put another way, our active engagement with the phenomenal world is more successful, at least in terms of prediction and control, to the extent that we base our decisions about what to do on views about that world derived from careful observation—observation that aims to set aside any psychological factors which might interfere with the phenomenal object presenting itself to us “as it is.”

Again, what is presenting itself to us when we strive for such objective receptivity is, from a Kantian standpoint, still the phenomenal object as opposed to the thing in itself. But there’s this sense that the phenomenal object that we encounter through such objective observation is more to be trusted. And so it’s quite natural to suppose that a phenomenal object received in this way—through purely receptive attention, or what is generally called unbiased observation—offers clues to noumenal reality that can be found nowhere else.

And this, I think, is the premise around which science grows. If we focus our attention on the objective pole of consciousness, and endeavor to adopt an attitude of pure receptivity to what the objects at that pole give to us, we can then begin to describe the phenomenal world at a level of detail that will uncover an array of clues about the reality that lies behind it.

We collect a set of observations—for example, the observations spelled out in the ideal gas laws. We note that at a constant temperature, volume and pressure have an inverse proportional relationship (Boyle’s Law). At a constant pressure, volume and temperature are directly proportional (Charles’ Law). At a constant volume, pressure and temperature are directly proportional (Gay-Lussac’s Law).

But instead of being content with merely describing these recurring patterns, we treat them as clues. We speculate about what the gases have to be like—and what pressure and temperature are really measuring—in order for these observations to hold true. We construct a mechanistic model: Gases are really tiny particles in constant, random motion. Pressure measures the frequency with which these particles strike the container in which the gas is housed. Temperature measures the velocity at which these particles are moving.

And so we now arrive at the kinetic theory of gases. But we ask ourselves why we should believe that this model captures the reality behind appearances. Since detached observation of phenomena brought us this far, we appeal to it again. We ask what else we might observe if this kinetic theory of gases is true. And then we try to observe it.

This process continues. The same “particles” that were postulated in the kinetic theory of gases come up in other models used to makes sense of other observations. While we cannot observe them directly, we use our growing grasp of the rules by which the phenomenal world works to create devices that “see” them for us. We make observations about them—and then proceed to model them to make sense of these observations. We conceive of them as made up of smaller particles—some forming a nucleus around which others orbit. We refine this model. We begin to examine everything, including our own bodies and brains, in terms of these powerful models. The models are progressively refined in the light of what we observe--and are themselves explained in terms of more basic models which postulate more basic particles and more basic rules (which we reify in terms of concepts such as “forces” and “physical constants”).

And at some point we become convinced that this picture has taken us beyond phenomena to reality itself. We think that what we are doing, as we engage in this process, is using the careful examination of the phenomenal world to piece together a picture of the underlying noumenal reality. The process that starts with ignoring everything in consciousness but what is at the objective pole, that proceeds by setting aside the influence of any elements of our consciousness that might interfere with pure receptivity to what the objective pole presents us with, and then lets the active element of ourselves back in at the point of constructing models to explain what is observed—this process is taken to put us in touch with noumenal reality, at least in part.  The pragmatic usefulness that this method affords in terms of prediction and control of the phenomenal world is take as evidence that we are steadily aligning our beliefs with the reality that lies behind appearances. And it is a short step from this judgment to the belief that this same process has the power, at least in principle, to give us all of noumenal reality, the whole world as it is in itself (if only we could somehow carry the scientific project to completion and generate a flawless unifying model of every empirical observation). And so, if anything is posited to exist which in principle could not be discovered through this process, then it is dismissed as "supernatural."

This is what I take metaphysical naturalism to be: the view that the picture of the world that emerges through the exercise of the scientific method (roughly as described here) is an exhaustive picture of the fundamental reality behind the world of appearances. In other words, it is the view that noumenal reality is to be identified with the scientific picture of the world—or, more precisely, with the picture of the world that the scientific method would ultimately produce if it were able to achieve and adequately test an ultimate model of everything. In any event, the idea is that science is bringing us ever closer to an exhaustive grasp of noumenal reality. As such, metaphysical naturalism is a much stronger view than the more modest thesis that science gives us insight into some important feature or dimension of noumenal reality, leaving open the possibility that there are things in the noumenal realm that science cannot even in principle get at.

And so, if the picture that emerges from this scientific process leaves no space for an understanding of ourselves corresponding with our immediate inner experience of ourselves as unified subject and agent, this is taken to show that the noumenal reality about ourselves is at odds with our phenomenal experience of ourselves. If the resultant picture cannot account for entities in the world possessing objective value, then our experience of such a thing must be a subjective projection, produced by an underlying physical reality (the brain)—another case in which noumenal reality is at odds with phenomenal appearances.

Now this identification of noumenal reality with the outcomes of an idealized science cannot be falsified through the scientific method, because that would require that the scientific method offer up a picture of reality at odds with its picture of reality. Science cannot directly access noumenal reality in some way independent of its methodology in order to show it to be at odds with the picture produced by science. Furthermore, if the noumenal reality is at odds with the scientific picture of things, it will likely be because the noumenal reality is related to phenomenal experience in something analogous to the way that the supercomputer-reality is related to the virtual experience of the brains-in-vats. In other words, if the identification of the scientific world picture with ultimate reality is wrong, it will be wrong for reasons that make it impossible to directly show that it is wrong.

One might think, however, that we should believe in the close correspondence between the scientific picture and noumenal reality unless one has been given good reason to doubt it. Unless we have good reasons to think there's a disconnect between appearances and reality as significant as what one has in the brain-in-vat analogy, one should trust that there isn't such a disconnect. Science gives us reason to think there is such a disconnect between everyday appearances and reality, but there is nothing comparable that provides us with reason to suspect a comparable disconnect between scientific appearances and reality. And so, we should trust that scientific appearances connect us with reality, and the default position should be metaphysical naturalism.

There are several problems here. First, there is the question of what is to count as a reason to suspect the identification of scientific models with noumenal reality. Many of the disputes in this blog turn on just this question--a theist offers reasons to be suspicious of the identification, and these reasons are dismissed because (a) they aren't the sorts of reasons that fit with the assumption that what can be scientifically modeled exhausts reality, and (b) scientific modeling provides a means of explaining away as predictable illusion the considerations that have been put forward to challenge the identification.

But let's set aside worries of this sort and accept as legitimate only the kinds of reasons for doubt that scientists typically treat as legitimate. If we do this, then the absence of reasons for doubting the identification of ultimate scientific models with noumenal reality doesn't say much. The absence of reasons for doubt counts in favor of a belief only if we would expect there to be reasons for doubt if the belief is wrong---but this is not the case with the identification between what science depicts and what is ultimately real. The absence of any such reasons for doubting the identification is just what we would expect were noumenal reality as inaccessible to real-world scientists as it is to virtual-world scientists in our analogous case.

Finally, let us return to thinking about the scientific method from our starting place in consciousness.  Science proceeds by intially bracketing (or setting aside for a pragmatic purpose) everything but the objective pole of consciousness. Metaphysical naturalism then identifies the whole of reality with what has been arrived at by paying exclusive attention to this objective pole. The subjective pole of experience, our sense of agency, the deepest longings of the soul, our values—these are reintroduced only once a holistic picture of reality has been constructed without them. Is it any wonder that, according to a holistic picture of reality embraced without paying any attention to anything but what we find at the objective pole of experience, everything other than what we find at the objective pole of experience is judged to be a phenomenal illusion?

Kant, by contrast, was more than prepared to consider the possibility that the scientific picture of reality left things out because, after all, it was just a picture. And so, for example, he looked at the self-understanding that comes from empirical investigation, according to which all things are mechanistically determined by pre-existing conditions and constant natural laws. He saw that this implies that our actions are determined rather than free. But for Kant, all that this showed is that the phenomenal self--the self as an object of experience--is determined. But that doesn't mean the noumenal self is. Moral agency, he argued, makes no sense apart from real freedom--but the determinism of the phenomenal self isn't therefore a bar to affirming moral agency, since we can postulate that the noumenal self is free. He called this a necessary postulate of practical reason (reason that is action-guiding), because in order for reason to be action-guiding the self must be capable of choosing to follow the dictates of reason rather than merely act mechanistically in accord with physical laws. While no scientific picture will show a self that can do this, such pictures are purely phenomenal. And so attributing such determinism to the noumenal self would be both unwarranted and inappropriate, since it would mean the denial of moral responsibility.

One might treat this as a kind of practical wager: Either we are morally responsible for our actions or not. Which is true depends on what the noumenal self is like, something we cannot know. We can postulate that the noumenal self is determined, that we have no moral responsibility for our actions, or we can postulate that the noumenal self is free and that we do have such responsibility. If we postulate the former and are mistaken, then we have abdicated a responsibility that we actually possess. If we postulate the latter and are mistaken, we are just as determined as we ever were. Kant thought that practical reason demands we make the former postulate--that, in other words, practical reason demands we reject metaphysical naturalism.

What I would add to all of this is that our intuitive sense of ourselves is one that affirms free agency. And the fact that the scientific method begins by bracketing all such intuitive affirmations so as to focus exclusively on the objective pole of consciousness is not a good reason to conclude that these intuitive affirmations are false. After all, we should expect that a model of reality that begins by setting these intuitive affirmations aside won't afford them a veridical place in the model.

Of course, it doesn't follow that these intuitive affirmations are true, either. And that practical reason demands that we postulate things about the noumenal realm that transcend what scientific modeling can endorse doesn't entail that the metaphysical naturalist's position is false.

So where does that leave us? It leaves us with metaphysical naturalism as a theory about ultimate reality that (as far as we can say at this point in our thinking) might be true but is hardly uncontestable. In my next post I want to consider a range of alternatives to metaphysical naturalism—not merely metaphysical supernaturalism, but also pragmatic naturalism (which Burk gestured towards in a comment on an earlier post in this series) and perhaps some other alternatives as well.