Wednesday, 28 September 2011

On critical thinking

Quantum Ergodicity

People tend to think in dichotomous ways. For example, if you happen to question the efficacy of various sorts of "alternative medicine," people will think you are an advocate of everything that the big pharmaceutical companies advocate. Really, though, those two questions are totally separate. A treatment associated with "alternative medicine" works (or not) because of whether it works, not because it is "alternative" or "natural." A drug developed by a drug company has the effects that it has, the efficacy (or not) that is has, because of what it does, not because of its origin. A scientific theory is valid if it works and produces the predictions it has predicted, not because it is "science."

  The quote above is from Jonathan`s blog called Stupid Motivational Tricks and is an example of a particular philosophical viewpoint called Instrumentalism.

 In the philosophy of science, instrumentalism is the view that a scientific theory is a useful instrument in understanding the world. A concept or theory should be evaluated by how effectively it explains and predicts phenomena, as opposed to how accurately it describes objective reality.
Instrumentalism avoids the realism/ antirealism debate andd may be better characterised as non-realism. Instrumentalism shifts the basis of evaluation away from whether or not phenomena observed actually exist, and towards an analysis of whether the results and evaluation fit with observed phenomena. (Wikipedia)

  The problem is that eventually new data is recorded which either contradicts the theory or lie outside the boundary conditions of the hypothesis. By Jonathan`s measure, Ptolemy's geocentric model of the universe would be ``valid`` since Ptolemy`s Handy Tables could predict the positions of the Sun, Moon and planets, the rising and setting of the stars, and eclipses of the Sun and Moon. The point is not to eviscerate J.`s line of reasoning but to emphasize the consequences of wrong assumptions even though the theory appears to work during a certain period of time. Neo classical economics also relies on Instrumentalism. The former éminence grise of the current flock of economists who got us into this mess was Milton Friedman who was also an Instrumentalist.  In a 1953 paper, he stated:

Truly important and significant hypotheses will be found to have “assumptions” that are wildly inaccurate descriptive representations of reality, and in general, the more significant the theory, the more unrealistic the assumptions. . . . The reason is simple. A hypothesis is important if it “explains” much by little, that is, it abstracts the common and crucial elements from the mass of complex and detailed circumstances surrounding the phenomenon to be explained and permits valid predictions on the basis of them alone. To be important, therefore, a hypothesis must be deceptively false in its assumptions; it takes account of, and accounts for, none of the many other attendant circumstances, since its very success shows them to be irrelevant for the phenomenon to be explained.

To put the point less paradoxically, the relevant question to ask about the “assumptions” of a theory is not whether they are descriptively “realistic,” for they never are, but whether they are sufficiently good approximations for the purpose at hand. And this question can be answered only by seeing whether the theory works, which means whether it yields sufficiently accurate predictions.

  This is a ``get out of jail`` card for such false right wing economic assumptions such as the rational expectations theory which says that people always act rationally using perfect information( i.e they`re omniscient) to maximize their utility so that an equilibrium price for the product in question is reached in which supply perfectly matches demand. This is the basis for the” Efficient market hypothesis” where the current state of the market represents the ideal situation since all information is present in the prices of the market. Spiro Latsis refers to this form of human behaviour as situational determinism where in any particular situation all people make the same choices – humans are an ergodicitic ensemble. If you partition the population into sub populations then the people in each partition will act like the people in each of the other partitions. This is closer to theology than science and definitely not the intuitive understanding of human nature but according to Friedman it doesn’t matter. This is why economists were caught flat footed in the 2008 crisis because according to their mathematical models it couldn’t happen. There was no variable for the massive fraud which was the fundamental business model for the financial sector and fraud is a type of asymmetrical information in which one party knows things that the other party doesn`t which implies imperfect information that according to the efficient market hypothesis and rational expectations theory can`t exist.

  So false assumptions can seriously screw things up eventually although at the time, they appear not to matter – you can use your alternative medicine for quite a while with the appearance of only beneficial effects but wait until your liver has an infection and can`t metabolise the active ingredient at the usual rate or your kidney has an infection and the excretion rate of the active ingredient drops. You could have a serious overdose taking the usual dosage and your alternative medicine man will not be up to the situation.

  Social scientists have a particular problem with expressing critical thoughts since chaos and transition are their equivalent of natural scientist`s controlled experiments. Like Heraclites, it`s hard to describe a moving river when it changes every time you step in it so you use fluff words like ``transgressive`` and liminality to discuss periods of change and cover up the level of perceptual ambiguity on the part of the observer. Free floating, self referential data sets like the Rosenberg self esteem scale with a variety of anchoring schemes using the opinions of experts and semi-experts are the norm. This scale was used in the infamous “debt increases student self esteem” paper which Clarissa and I discussed a while ago. I could make quite a long list of dubious assumptions in this paper which is another instance of Instrumentalism as well as ergodicity where a stochastic system of student outcomes tends in probability to a limiting form which is independent of the initial conditions. (To be continued)

1 comment:

  1. Tres bon post and importante.

    You know, when you comment on blogs your link is dead, you don't put in the right syntax, I mean the complete URL, is this on purpose?