jump to navigation

Introduction to Radical Constructivism III January 16, 2007

Posted by caveblogem in Constructivism, Other, Philosophy, postmodern, postmodernism, science.

I have looked at my previous postings on this subject and they appear long-winded, flippant, and needlessly argumentative.  Indeed, I think that it is possible I have started out on the wrong foot entirely.  Postulate number one really should be something like postulate number 10.  There is too much to cover for anyone not already convinced could take it seriously. 

So let me try again, building up from smaller assertions.

Postulate Number I (revised)–The process by which we acquire knowledge is limited, hobbled, and distorted by a number of things.

Example A: Consider that our brains can process recieve something like 10,000 sensory inputs per second, but can process only a small fraction of that input. 

Example B:Consider that our brains play tricks on us, making up information about the outside world and trying to pass it off as input.

An experiment you can do at home–The Blind Spot

  1. Take out a blank piece of paper. 
  2. Draw a star in the middle of it about an inch from the left-hand side, bigger than the diameter of a pencil, but a little smaller than an IPod ear-bud. 
  3. Three and one-half inches to the right of the star, draw a dot, approximately the same size as the star.
  4. Hold the paper in front of you, about six inches away.
  5. Close your left eye and stare at the star with your right one.  (The star should be directly in front of your right eye.)
  6. Slowly move the paper away from you while staring at the star.

At a point around 10-11 inches away from your eye, the dot will appear to cease to exist.  The paper will appear to be blank in the spot where the dot was, unless you move your right eye away from the star to look at it.  You have a blank spot in the photoreceptors that receive light in your eyes.  Your brain constantly fills in these spots with information from your other eye, or if that eye is closed or missing, from your short term memory.  It constructs this picture you think of as “reality.”

Example C: Consider that when painters wish to see the “true” color of an element of “reality” that they are painting (especially when out-of-doors), they make a hole in a card, and look at the element through that hole, diminishing the effect that the surroundings have upon the brain’s perception of the element.  In other words, people look at trees and think of their trunks as brown and their leaves as green, while the light that actually bounces off the trunk can appear green, black, grey, red, or many other colors, depending on the position of the sun, the condition of the atmosphere, and, especially important to landscape painters, the distance from the painter.



1. anxiousmofo - January 16, 2007

Those examples can also be used to make the point that our senses do not present a real world, but a construct which can differ from the real world. That much I would agree with.

In your earlier post, you discuss the possibility of using a Ptolemaic model to get a spaceship into orbit, rather than a Copernican. This seems to be establishing that we can judge scientific models by their usefulness rather than how closely they approximate the truth. This raises the question: how can one judge the usefulness of a scientific model outside of the assumption that a scientific model actually relates to real entities?

(I should probably mention that your posts are my first introduction to Radical Constructivism.)

2. caveblogem - January 16, 2007


Thanks for joining the discussion. (By the way, I saw your post the other day on Infinite Jest (the musical), laughed out loud, and almost responded to it, but couldn’t think of anything to say.)

Good questions. For me, the beauty of the second and third examples is that they rely on our own sense perceptions to dispute what we see, rather than referring to a “real world.” They were consciously chosen for that very reason, because everything one tries to say about the relationship between a “real world” and a “constructed world” necessitates, for me, some sort of proof that there is a real world that is accessible to us. And I don’t think that it is possible to prove that. And I don’t think it is necessary, either.

Personally, I would judge scientific models by their utility. That seems reasonable. We could judge them by their value in the market. Inherent beauty, symmetry, the accuracy with which they incorporate theological presupposition, etc., have also been used as criteria, but are rarely used these days. But since we can’t know “the truth,” the model we are trying to represent, how can we discuss the distance between our model and this thing we cannot judge?

3. anxiousmofo - January 16, 2007

I’m glad you liked my “Infinite Jest! The Musical!” post! I’d wondered if anyone had actually read it :)

I’m not arguing for direct realism. What gets to us through our senses is a model of the world, not the world itself.

What we find in this model is a number of regularities and consistencies. We encounter patterns of sense impressions which we can recognize as our family members, cars, offices, laptops, etc. We can make useful predictions, e.g., if I pick up the mug next to me on my desk and drop it, it will fall. These regularities do not necessarily exist in dreams, nor do they necessarily exist when experiencing hallucinations caused by hallucinogens or mental illness. The most parsimonious explanation for these regularities is that they are caused by real objects and events. Other options (I’m a brain in a vat, I’m under the control of the Matrix, Descartes’ demon is taunting me) require an explanation of why I am the only mind in the world, or why someone is going to all this trouble.

I would argue that we can approach the truth, and possibly even know the truth. The utility of a scientific model (whether it makes useful predictions, whether it agrees with observation) is the best way to judge it. But I suppose I am making the (possibly naïve) argument that a scientific model which is useful is also a scientific model which bears some relation to the truth.

4. caveblogem - January 17, 2007

I don’t think that there is necessarily anything naive about that argument, anxiousmofo. The sticking points for me are (1) that there doesn’t seem to be any way to measure the distance of our models from that “truth,” since we don’t have any access to that “truth,” and (2) that nobody seems to be able to tell me why it would be important to go to the trouble in the first place.

If one model makes useful predictions and fits well with its observations, and then another comes along and does a better job with both, is the second closer to “truth”? I dunno, but whether it is or not doesn’t seem to be important in judging the model.

Lets say that the predictions of the first model predicts almost as well as the second and agrees nearly as well with the data. If the first model is much simpler, and the consequences of being wrong in our predictions are not dire, then I think that most logicians would agree that we should use the first and scrap the second (Occam’s Razor). Many existing models are the product of this sort of reasoning, rather than the “use the one closest to the “truth” sort.

There seems to be no remedy to these issues without redefining “truth” as something like “fits really well with the observations and makes really useful predictions.”

5. anxiousmofo - January 17, 2007

A scientist will use Einstein’s much more complex model in some scenarios, while NASA might use Newton’s simpler model to lob a satellite up into orbit. A good reason to consider Einstein’s system more true is that it fits better with observation and makes more accurate predictions. That Einstein’s model has less utility (in terms of complexity and the time it takes to solve the equations) in some situations does not make it further from the truth than Newton’s in those situations.

As something of a realist, I argue that we do have access to at least some of the truth, mediated as it may be, and that the scientific method is one way of measuring the distance between at least some of our models and the truth. But I wouldn’t agree that this means that truth is now defined as “fits really well with the observations and makes really useful predictions,” because truth value isn’t the same thing as verification methods.

To answer your question 2, here’s a thought experiment (or, more honestly, an intuition pump). Suppose that you have been happily married to someone you love for twenty years, a kind, intelligent, attractive person named Pat. One day, Pat’s doctor informs you that Pat is a philosophical zombie. Pat has no mental states at all, and only appears to love you in return. The hypothesis that Pat loves you and enjoys being with you and is committed to you is consistent with all the data and makes useful predictions about how Pat will act towards you; it just happens to be false. Wouldn’t knowing that make a difference to you? Similarly, if what I see as objects and people in the real world don’t actually exist, my life would be meaningless.

Of course, the notion that Pat (or anyone else) is a philosophical zombie is an extremely far-fetched and unparsimonious* notion, and so (I would argue) is the notion that the world we experience is unrelated to the real world, or the notion that there is no real world.

*Unparsimonious because it would require that there be at least two kinds of people in the world, those with mental states and those without.

6. SilverTiger - January 18, 2007

Welcome to the debate, anxiousmofo. You have answered the points raised in caveblogem‘s post so well that I’ve a good mind to goof off on this one and not post my own reply!

I will do so, however, being an honest tiger, but my answers will almost certainly duplicate yours.

Glad to have made your acquaintance.

Email SilverTiger

7. Debate on Constructivism 3 « SilverTiger - January 18, 2007

[…] on Constructivism 3 This is my response to caveblogem’s third post on Radical Contructivism. For convenience of reference I reproduce the postulate from that post but readers would be advised […]

8. anxiousmofo - January 18, 2007

And I’m glad to have made yours, SilverTiger. I have to tip my hat to your responses as well.

9. BigBoomer - July 31, 2007

see filmsbuy.com site with thousands movies for downloads!! it is legal or no?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: