A rant about perception

I follow the blog “Notes from Two Scientific Psychologists“. The authors are perceptual psychologists. In the a recent post they attempt to explain the distinction between whether perception is direct or indirect. This post is by Andrew, though both of the blog authors agree that perception is direct.

I happen to agree that perception is direct. But I disagree with a lot of what Andrew says in his post. Hence my comments may look like something of a rant.

I’ll be quoting from Andrew’s blog post. The wordpress software formats quotes in a distinctive way, so I think the reader will be able to tell when I am quoting.

Andrew begins with this:

All theories of perception begin with the fact that we experience a rich, detailed world full of things we can and can’t do, should and shouldn’t do. Specifically, we experience a behaviourally relevant world.

I can fully agree with that statement. So at least we begin with agreement.

Indirect perception

Andrew then gives his characterization of indirect perception:

Indirect theories begin with the assumption that the world does not present itself to us in behaviourally relevant terms, and that we therefore need at least one mediating layer between us and the world in order to transform the way the world presents itself into the way we experience the world.

Interacting with the world

Here’s something to try:

With your eyes closed, touch the tip of your nose with your finger.  You will probably find that you are fairly good at it.  Not perfect, but still pretty good.

Or try to touch your ear lobe, again with your eyes closed.  Or try to touch your eyebrows with your eyes closed.

Monitoring your actions

What is happening there, is that your brain is tracking your finger even when you cannot see it.  And your brain is also tracking your nose, eyebrows and ear lobes.  The brain is monitoring your activity.  And a good part of your abilities to interact depend on this monitoring.

While walking, you step on a banana peel, or something else that is slippery.  Maybe you will fall.  But, most of the time you are able to recover your balance without falling.  And that’s because of the monitoring that your brain is doing.  As you begin to transfer weight to that foot, the brain detects a problem and you are able to react before you have fully transferred weight to that foot.

Proprioception

Much of this has to do with proprioception, which is that part of our perceptual system that handles such monitoring.

Sharing concepts with the culture

In my previous post, I discussed carving up the world.  The idea is that we carve the world and give names to some of the parts into which we carve.  Those named parts become the concepts that are part of the true statements we make about the world.

In an earlier post, I indicated that how we carve up the world needs to be a social convention.  And the naming that we use also needs to be a social convention.  That these are social conventions is what allows us to communicate with one another.

In this post, I will be discussing how these social conventions can be established.

The culture

By the culture we mean, roughly speaking, the society and the social practices of people within that society.

We cannot share  things with the culture until there is a culture.  Picture the problem for young child.  She needs to learn how to carve up the world in order to fill her world with details.  So the need to carve up the world starts before the child has much of a world.  In particular, the child needs to start carving up the world before she can become aware that she is part of a society.  In other words, the carving up must begin without access to any carving conventions from the culture.  The child must initiate carving by herself, and not wait until she learns what are the social conventions.

Carving up the world

It is said that we carve up the world at its seams.  I doubt that there are any seams.  We carve up the world in ways that are easy enough and that we find useful.  But those requirements — that it be easy enough and that it be useful — underdetermine how the world is to be carved.  So it is a matter of pragmatic decision making.

As we saw in my last post, carving up the world is what gives us the entities that we can talk about and is what allows us to say true things about the world.

I should say at the outset, that carving up the world isn’t an entirely conscious and deliberate activity.  Much of the work is done behind the scenes by our perceptual systems.  So, in part, this post is related to how perception works.  So when I talk about us carving up the world, I am not restricting this to conscious activity.

Why it is hard

We cannot just look around and see what are good ways of carving up the world.  To be able to look around and see, then what you are looking at has to have a lot of detail.  But the detail that we see gets there because of how we carve up the world.  So we cannot presuppose that it is available before we do any carving.

Color blindness

I am color blind.

Well, not really.  My color vision is fine, thank you.  However, my color vision is abnormal.  That doesn’t mean that it is bad.  It just means that it is different from what is typical.

I should note that I am posting this because I intend referring to it in a future post about human cognition and perception.

Growing up

As a child, I had no idea that there was anything unusual about my color vision.  The world looked the way that people described it, as best I could tell.  I developed an interest in electronics, and I never had any difficulty with the color coding of resistors and other components (giving the resistance as a series of color bands).  As far as I could tell, my vision was normal.

Searle on direct realism

As I hinted in my previous post, I want to discuss some aspects of Searle’s theory of perception.

Searle makes a good start with:

I believe the worst mistake of all is the cluster of views known as Dualism, Materialism, Monism, Functionalism, Behaviorism, Idealism, the Identity Theory, etc. The idea these theories all have in common is that there is some special problem about the relation of the mind to the body, consciousness to the brain, and in their fixation on the illusion that there is a problem, philosophers have fastened onto different solutions to the problem. (page 10).

I agree that those are mostly mistakes.  Searle continues with:

A mistake of nearly as great a magnitude overwhelmed our tradition in the seventeenth century and after, and it is the mistake of supposing that we never directly perceive objects and states of affairs in the world, but directly perceive only our subjective experiences.

That is Searle’s statement about his direct realism.  I do support the view that perception is direct, but I avoid the term “direct realism” because the word “realism” seems to carry some unnecessary metaphysical baggage.

Constrained invention

This will mostly be a copy of what I recently posted in a Yahoo groups discussion.  And, incidentally, Yahoo badly mangled that post (stripped out most of the formatting).

As background, I’ll note that in an earlier Yahoo groups post, I had indicated that I was opposed to the view that perception is passive.  This seemed to puzzle some participants in the discussion.  So my post — the one I am quoting — was intended to explain what I mean when I say that perception is active.

The quoted post

You guys need to get out more. You are trapped in a world of logic, and unable to think outside that box.

You both seem committed to God’s eye view thinking, though you may be in denial over that. So you see perception as a system to report to you what is seen by the hypothetical God. But how could that ever work?

Direct vs. representational perception — the discussion

In prior posts (here and here), I have illustrated representational methods and direct methods.  The illustrations were from science, because that is more public so easier to demonstrate the contrast.  I believe that they illustrate well enough, the distinction between direct and indirect perception.  Both aim to provide the same sort of information about the world.  The method is different, though perhaps the differences are small enough to be confusing.

The primary distinction here is that direct perception is simpler and more direct, and does not rely on computation or inference.  This is why I see direct perception as more likely to be what has evolved, and thus a more likely candidate for explaining human perception.

Double categorization

One way of seeing the distinction is to look at it in terms of categorization.  Here, I use “categorization” to refer to the dividing up of the world into parts (or categories).  This comes from the old idea (from Plato?) of carving the world at its seams, though the seams might actually be man-made.

Direct measurement of temperature

In an earlier post, I described the representation measurement of temperature.  In this post, I describe the direct method.  The contrast is intended to illustrate the distinction between representational theories of perception and direct theories of perception.  By using an example from science (or perception written big), we illustrate in a way that is easier to see.

The design of the instrument

The design is almost the same as described in the earlier post.  There is one addition.  The mercury column in the capillary tube is directly calibrated in temperature.  That is to say, there are graduation markings on the thermometer, from which we can directly read off the temperature.

Representational measurement of temperature

As indicated in the previous post, I plan to use the measurement of temperature to illustrate some ideas about perception.  This post will give a representationalist account of measurement, as an illustration of indirect perception.

The apparatus to be used is very similar to a mercury thermometer.  I shall assume that the reader is reasonably familiar with traditional analog thermometers, and how they are used.

The design of the instrument

The thermometer uses a glass tube.  At the bottom of the tube, there is a largish bulb which can be filled with mercury.  Above the bulb, the glass tube contains only a very narrow tube of small diameter, sometimes called a capillary.

The bulb is initially filled with mercury, and the mercury extends to part way up the capillary tube.  Above the mercury, the tube is empty.  The air is pumped out, though it need not be a perfect vacuum.