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March 29th, 2009

Fifth Sunday in Lent

Food for Thought

Eating assimilates an object to a subject by destroying the object.  Knowledge assimilates an object to a subject by preserving the object. To doubt the objectivity of knowledge requires that we be confused about the difference between knowing something and eating it.
-- James Chastek

Yet, this has been confused in modern thought.  Understandably so, because the perceived object only exists within us as a change-of-state of our own body.  Sights and sounds and such are neural patterns in our own brain and so, by definition subjective.  This little worm has been eating out the apple of the Enlightenment from the get-go, since it was introduced by Hume and Kant themselves.  Hence, the reinterpretation of knowledge as nothing more than the power interests of the subject.  With Popper and the rest, it has reached the scientific core.  We now believe that not even scientific knowledge can be held for certain.  (This, in face of the circulation of the blood, the spectrum of white light, and the distance traveled by a falling body as being 0.5gt^2.)  And so we end up with Kuhn (he of "paradigm" fame) telling that the Ptolemaic system is "just as true" as the Copernican. 

And all because moderns take things wrong way round.  We go for the more abstract.   Aristotle always started with the more empirical, and so he started with eating food. 

When we eat something we assimilate it in a very definite way.  The food actually becomes part of us.  [Too much a part, in my case.  :-(  ]  When we sense something, we also assimilate it and it also becomes a part of us -- we speak of "sense impressions" as sealing wax is impressed by a signet ring -- and likewise when we understand something.  How often do we talk of "taking in" a movie or "taking in" a lecture? 

Now, it's easy to see that knowing and eating are different, but it's not so easy to say just how.  And so Kant''s error was to confuse knowing with eating absolutely.  In effect, he wrote "a priori categories of possible experience" instead of "stomach," and "a posteriori sense experience" instead of "food."  As Chastek puts it, Kant used cognitive terms to speak about digestion -- and called it reasoning. 

One could teach the whole history of modern epistemology, he writes, as an overlooking of the distinction between eating and thought. From Descartes onward, the assimilation of the object into the subject is seen in a way that the object must be consumed or destroyed in its objectivity in order to be a part of a subject.  [Emph. added]

Of course, knowledge really is a kind of assimilation.  It does draw something in from outside ourselves.  But "assimilation" conjures images of the Borg: "surrounding something" and "making it a part of our own substance."  

And so the Stagerite imagined knowledge to be something different from eating.  He discusses it only after an exposition of the object of eating and of sensation, so he did not confuse the different kinds of objects.  While the object of digestion is assimilated by being destroyed, the object of knowledge is assimilated precisely by being preserved in its own existence. The scholastic definition of knowledge was "to be the other as other."   Which is why to know another person is a very intimate thing indeed. 

An article at Wired revives thoughts about the inadequacies of models. 

The problem with simulations (imho):

1. The Forgotten X.  If you model output Y as Y = f(X1, X2, ... , Xn) you will always miss an X or two.  

2. The Boundary Value.  The relationship between Y and any of its X's will almost always go through a singularity where the relationship itself changes.  When food is heated, biochemical processes speed up.  Hence, manufacturers will store food at elevated temperatures to accelerate aging for shelf life testing.  But if you raise the temperature too much you cook the food.  You cross over into a different "regime."  You cannot predict the cliff from the flatness of the plateau. 

3. The Approximation of Fit. 
A mathematical model is only an approximation to reality.  (And Fie! upon you Platonists!)  Models always make simplification assumptions: for example, that a model is a linear sum of the X's.  This is often true locally, but outside the immediate locale, the curvature begins to be felt.  Newtonian mechanics works splendidly -- except for the very fast or the very small.  The bell curve is a good model for many things: but the bell curve goes to infinity in both directions, and no real world process does.  So models tend to either over-estimate extreme values or underestimate them.  This is different from the Boundary Value: it is not that the relationship changes, but that the error in the model increases.  It isn't =really= a bell curve.  It just looks like one when you're dealing with central values.  But the tails don't fit so well. 

Whoops.  Never Mind. 

You won't see any big headlines on this. 

Correlation between Cosmic Rays and Ozone Depletion

Q.-B. Lu
Department of Physics and Astronomy,
University of Waterloo, Waterloo, ON, N2L 3G1, Canada


This Letter reports reliable satellite data in the period of 1980–2007 covering two full 11-yr cosmic ray (CR) cycles, clearly showing the correlation between CRs and ozone depletion, especially the polar ozone loss (hole) over Antarctica. The results provide strong evidence of the physical mechanism that the CR driven electron-induced reaction of halogenated molecules plays the dominant role in causing the ozone hole. Moreover, this mechanism predicts one of the severest ozone losses in 2008–2009 and probably another large hole around 2019–2020, according to the 11-yr CR cycle.

Percentage variations of CR flux (solid magenta line)
and annual mean total O3 measured at two Antarctic stations,
Faraday/Vernadsky (in red and green).


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