Debate 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 to read the post for themselves (by clicking on the above link) as well as the rather interesting comments added to it.

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

The idea that we are somehow prevented from knowing the world “as it really is” because we have to receive information about it through an imperfectly functioning nervous system and process these “data” with an imperfectly functioning brain strikes me as paradoxical. It reminds me of evangelists who postulate that we are in a state of mortal sin so that they can sell us the salvific remedy. If you reject the proposition, the need for a remedy disappears.

I have difficulty understanding what this “world as it really is” is supposed to be. If I am incapable of knowing it, how do I know it exists? In order to say that View A of the world is inferior to View B, which is the world “as it really is”, we surely have to produce View B for all to see and to compare Views A and B. If View B is unobtainable then by what right do we dismiss View A as inferior to it?

In case you think this is mere hair-splitting, let me state it again succinctly: in order to evaluate our view of the world as good or bad, true or false, we need a measure against which to evaluate it. The only measure that the Radical Constructivists seem to offer us is “the world as it really is” which they assert is inaccessible to us. That being so, no evaluation is possible. It’s a null match.

I know what the problems are supposed to be. Inter alia, they are set out in Bertrand Russell’s The Problems of Philosophy. My short summary goes like this:

Look at a table: what do you see? You see a rectangle – or is it a trapezium or is it a rhombus? – that changes shape as you approach, retreat and move around the table. It is brown – or is it? It has a white patch on it where light from the window is reflected from it to your eyes. The white patch changes place, shape and colour as you approach, retreat and move round the table. (And so on and so on.) This being so, that the table changes its appearance at every instant, how can we say that we really are seeing the table “as it really is”?

I think our first response must surely be to ask “What do you mean by ‘the table as it really is’?” Why do you think there is something else; can you show me this something else? If not, why do you assert that there is a something else? You claim that my knowledge of the table is at best indirect but I can at least point to data coming from that table whereas you do not even have indirect evidence for this putative alternative “world as it really is”. You are merely postulating it.

Yes, tables change their appearance according to how we look at them and the eye is subject to optical illusions. Percival Lowell did see “canals” on Mars where better pictures show dots and patches but what does this prove? The “real world” does not stop at the surface of the eye. It continues through the eye, up the optic nerve, into the brain. The “canals” that Lowell saw were part of the real world.* They were the dots and patches on the surface of Mars as “imaged” by the low-resolution human eye. A camera attached to a low powered telescope will produce a similar result. A more powerful telescope will “resolve” the dots and patches and show them as such. We know all this: it is familiar ground for a scientist.

Science describes the world. It describes it in human terms but what other terms are there? Do we know that there are any other terms? Doing science is like doing a jig-saw puzzle: you fit the pieces together to form a picture. The difference is that as science proceeds, the pieces change; we acquire more of them and the resolution improves. Therefore the picture we are building improves. We are building a picture, not a world. No one says that the world resides inside a physics textbook. The world is all around us, we are part of it and we are learning about it, building pictures of it to help us understand it.

In sum, I agree that “The process by which we acquire knowledge is limited” but I don’t agree that it is “hobbled, and distorted”.

“Hobbled” implies that the mind is not being allowed to operate to the limit of its capacity but is being held back by something. By what? The mind is the mind and it works as it works. No one is putting shackles on it. Any limitations are inbuilt and science is in the business of stretching its capabilities to the full.

“Distorted” implies that we have an undistorted view with which to compare it and see that it is distorted but this is precisely what the Radical Constructivists deny that we have.


*I have every regard for Lowell but think that on this occasion he let his imagination run away with him. As a scientist he should have suspended judgement until he had sufficient evidence.


About SilverTiger

I live in Islington with my partner, "Tigger". I blog about our life and our travels, using my own photos for illustration.
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5 Responses to Debate on Constructivism 3

  1. caveblogem says:

    As I have said elsewhere, the beauty of the Blind Spot experiment decribed in that post is that it does not rely on a “real world” for proof that the mind distorts its own sense data. During the experiment one presents one self with two different visions of the “world.” In one, the spot appears; in the other, it is not apparent. Unless one believes that the spot vanishes whenever one eye is closed, etc., or one believes that both visions represent “the real world,” then one is faced with discounting at least one of those visions.

    There is a case to be made for the idea that both visions are distortions: in one our mind fills the blind spot with white, in the other it fills it with white. Do the experiment with white marks on a black sheet and you will find that the mind fills the empty spaces with black. Do it with chartreuse, . . . But my point was merely that in at least case the mind distorted the inputs.

    So perhaps that postulate is better phrased thusly: Our minds distort, limit, and hobble the process by which we acquire knowledge. But to say that the Blind Spot experiment depends on some hypothetical “real world” for us to judge it? That I don’t understand. Did you really mean that, SilverTiger?

    SilverTiger says, above, “I have difficulty understanding what this “world as it really is” is supposed to be. If I am incapable of knowing it, how do I know it exists?” I also have this difficulty. I didn’t introduce the concept. And I would argue, and have argued at length, that you do not know that it exists.

    The measures I have introduced to evaluate different views of the world are functional and personal: Does this get me into orbit (or do I sense that these equations result in my going into orbit)? Is this vision different from this other one? Is this vision simpler than the other one? These do not require any outside measure to evaluate against.

    They also do not require values such as “true,” “good,” or “bad.” I haven’t tackled the logic of the whole thing quite yet because I’m afraid of losing our audience, but I believe that this worldview can get along with only the value “false.”

  2. SilverTiger says:

    I don’t see your blind spot experiment as particularly significant, I’m afraid. We know that all instruments used to study the world have limitations. This is as true of manufactured instruments as of the eyes and ears. Defects or limitations in the instruments do not alter the world in any way. All that we learn from the fact that there is a blind spot in the eye is that there is a blind spot in the eye. The spot on the paper does not cease to exist: it is there whether the eye sees it or not. All it means is that there is a known defect in the “instrument” (the eye) which we know about and allow for. Take your experiment to the extreme and ask what happens when a blind man “looks” at the world. Does the fact that his view of the world is blackness mean we have to discount the sighted person’s vision of the world?

    You say there is a case to be made that both visions are distortions. Well, you can so regard them, if you wish but, “visions” are not the world. The fact that two visions differ is not significant in my opinion. In fact, it may even help us get nearer to the reality. For example, astronomers often take photos through coloured filters because a body seen at different wavelengths may reveal features not apparent in integrated light. No one would say that because Mars in blue light looks different from Mars in red light, these views are “distortions”.

    Yes, I do say that your “distorted” visions depend directly on the real world. That is self evident from the fact that the objects you are looking at are real-world objects and your optical system is part of the real world. Change the objects and you get a different “vision”. (Does the spot disappear when an eagle or an ant looks at the paper? Maybe in their case there are other “distortions”.) The disappearing spot is the result of your human optical system interacting with the world. If the world, or the optical system, were different, the experiment would give different results.

    It seems to me that your theory does require a pair of evaluators, “good” and “bad” or “true” and “false”. This is because you claim all visions of the world are “distorted” and this can only be the case if there if there exists an undistorted vision from which these deviate. Distortions imply something that suffers distortion. If there is not, then your vision is the only one and is just “the vision” and distortion doesn’t come into it.

    Your claim that we only know about the distortion from the fact that different visions differ in their distortions does not avoid this problem because you either have to accept that one of these visions is true and all the others false or that all of the visions are false in which case they deviate from the vision which is true. Either way, your claim of distortion implies a real, undistorted, world.

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  3. caveblogem says:

    I was trying to lay out my point of view, step by step, but we seem to be talking past each other, SilverTiger. I really can’t continue without at least this first point: Our minds distort the process by which we acquire knowledge.

    Your comments have helped me to refine what I was trying to say several times, and although, like you, I have been frustrated that we have been unable to reach anything like common ground, I appreciate your willingness to debate this with me.

    I will, of course, continue to read your posts here, SilverTiger. You have many keen insights and are always an interesting read.

    Thanks for having me, SilverTiger!

  4. SilverTiger says:

    I’m sorry you think we are “talking past each other”. I obviously don’t think so but I respect your perception.

    It is obvious that we hold contrasting views but this by itself does not imply that we cannot understand one another. I believe I have understood your assertions and responded fairly to them. Possibly I am mistaken.

    Either way, I hope you have found the exercise of setting out your ideas useful and if, as you say, I have helped you refine what you were trying to say, I am glad.

    Email SilverTiger

  5. Pingback: Debate on Constructivism last « SilverTiger

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