Realism

by Neil Rickert

The idea for this post started when I read “Stephen Hawking’s Radical Philosophy of Science“, a post by Michael Shermer over at the Big Questions Online site.  But my thoughts soon drifted, so this post actually says as much about my own ideas of reality as it does of the ideas expressed in the Shermer post.

People reading my posts here and the things that I say elsewhere, sometimes conclude that I have weird ideas, and they wonder whether I think that the world is a creation of the human mind.  However, my position on realism, on what is the nature of the world, is actually quite close to that of naive realism.  When I look at that smooth surface of my desk, I understand that it isn’t really as smooth as it looks, so I can’t say that the world is exactly as it looks to us.  But the way it looks to us is a pretty good approximation.  So if I seem to have weird ideas, that’s for a different reason.  It is because when I see what people say and write, I can see that they are making unstated assumptions, often assumptions that they are not aware of.  So I have been looking at those unstated assumptions, and questioning them.  It seems to me that questioning unstated assumptions is something that philosophy should be doing.  Too often, philosophy seems to be failing us in that regard.

Returning briefly to the cited post, we see Shermer saying:

None of us can ever be completely sure that the world really is as it appears, or if our minds have unconsciously imposed a misleading pattern on the data. I call this belief-dependent realism.

And that’s an example of where my own realism disagrees with Shermer.  For sure, there is much in our world that is socially constructed.  Our monetary system is a social construct.  Our highway system is a social construct.  That the week is 7 days results from a social construct.  There is much that we do in our ordinary lives that is shaped by social constructs.  But, beneath all of that, there is an underlying reality that is not dependent on our beliefs.  The main point of Shermer’s post is to criticize the model dependent realism of Stephen Hawking.

Here is another interesting quote from Shermer’s post:

Do you think that there is a computer screen sitting in front of you right now?

It would certainly seem so if you are reading these words online, but in fact you are not actually “seeing” the computer screen in front of you. What you see are photons of light bouncing off the screen (and generated by the internal electronics of the screen itself), which pass through the hole in the iris of your eye, through the liquid medium inside your eye, wending their way through the bipolar and ganglion cells to strike the rods and cones at the back of your retina.

That’s a view that is very common.  It is sometimes called “indirect realism” or “representative realism”.  According to that view, we are not seeing the world.  Rather, we are seeing something else.  We are either seeing an image projected on our retinas or we are seeing an image constructed in the brain or, as Shermer suggests, we are seeing a pattern of photons.

Perceptual psychologist J.J. Gibson criticized such representationalist views, and instead offered his direct realism.  According to Gibson, we directly perceive things in the world.  Of course the light, the retina, the neurons are all used as part of how we perceive things, but our perception is direct.  We are not forming internal copies, and then in turn perceiving those internal copies.

To someone familiar with the physical sciences, representative realism seems at first to be the obvious conclusion.  It is based on the causal connections that we describe in giving a physicists view of vision.  However, there is that difficult concept of seeing, which is not a concept from physics.  If we follow the representative realists approach, then it seems obvious that we can get data about things in the world.  What remains unexplained, however, is how you get from data to seeing.  And that, roughly, is the Chalmers Hard Problem.

Even without worrying about the hard problem, there are difficulties for representative realism.  It’s a view that I started with, but had to drop when I realized that it did not answer the problems that faced an organism needing information about what is happening around it.  The big problem with representative realism, is that there is a lot of complexity involved in constructing internal images, and then analyzing those images.  If we were designing a robot with representative realism, then we would design the image forming system in accordance with strict standards.  And we would have to carefully align the parts so that they met those standards.  Roughly speaking, representative realism depends on adherence to something like a set of external standards.  But the capacity of the DNA seems rather too small for it to be a carrier of those standards.  So it seems more likely that you would want a system where an organism develops its own internal standards, and develops those internal standards based on perceptual experience.  With representative realism, you need the standards in place and working before there could be experience.  With direct realism, there is the possibility of developing standards, and an experience that becomes more detailed as internal standards are developed.  That is, there is the possibility of the perceptual learning that I discussed in my Camera Analogy series of posts.

Gibson’s direct realism is not without its own problems.  It is often said that it is not a physical theory, and that is already a problem.  Gibson did actually say something about the physical basis for direct perception, but what he said was too vague for my liking.

Shermer describes the Hawking view as

based on the assumption that our brains form models of the world from sensory input, that we use the model most successful at explaining events and assume that the models match reality (even if they do not), and that when more than one model makes accurate predictions “we are free to use whichever model is most convenient.”

I disagree with the Hawking view that we form models.  However, as discussed in my camera analogy series, we use some sort of apparatus to get information about the world.  And, in terms of the camera analogy, it doesn’t matter whether I use the infra-red camera, the ultra-violet camera, the wide angle lens, or the telescopic lens, as long as it provides me with the information that I need.  But all of those sets of apparatus are picturing the same reality, and we can usually switch between them with ease.  Similarly, when we study light as wave motion, then switch to studying it as photons, that is much like switching lenses.  We are changing the apparatus we use to view reality, but we are still viewing the same reality.

I guess I partly agree and partly disagree with Hawking.  I disagree with the view that we are using models, and I disagree that the reality we see is dependent on that model.  However, I agree that the way we talk about reality depends on which theory we are using.

Shermer goes on to discuss the change from Ptolemaic astronomy (or geocentrism) to Copernican astronomy (or heliocentrism), and he argues that the heliocentric system provides the better model.  However, I think that what we should learn from that historical change is that there is no such thing as absolute motion.  There is only relative motion.  The geocentric system describes motion relative to the earth, while the heliocentric system describes it as relative to the sun.  Galileo and Newton recognized that there is only relative motion, and that recognition is incorporated in the first of Newton’s laws.  As a naive realist, I’ll add that our perceptual systems seem to have no problem with that.  When I am aboard an airplane, I find that I am perceiving motion relative to the plane.  When I am on a train, I normally am seeing motion relative to the train, though if I concentrate on the outside scenery, I can instead see motion relative to the ground.  It seems that our perceptual system is really just choosing a suitable frame of reference for what we are currently doing, and observing motion relative to that frame of reference.  So naive realism is thus entirely compatible with the relativity of motion.

In a way, this brings out one of the problems of representative realism.  If we are really perceiving an internal image, as indirect realists insist, and if that indirect image varies with the assumptions we are currently using (geocentrism or heliocentrism for example), then our assumptions do change the reality that we are perceiving.  If, however, we directly perceive the world, as direct realists assert, then we are always perceiving that same world and merely switching between different choices of apparatus that we can use to see that world.  And I think that is the better way of understanding our relation to reality.

Advertisements
%d bloggers like this: