Wednesday, December 10, 2014

Inside Black Boxes: Survey Research, Fieldwork, Ground Truth, and "Effective Field Theories"

Often a presentation starts with some sort of data set they are analyzing. Some of the time they have generated the data set on their own with systematic and effective survey work, some of the time it is from various governmental or health files. What is striking to me is that whatever these people are studying is in effect a black box, when in fact they could enter the box and find out better how it works. Fieldwork is a very different style of research. Some times it is referred to it as "anecdotal," while I believe that "ground truth" is more appropriate. You want to see if what there is inside these boxes makes sense in terms of the characteristic of the box. To my mind, I want to understand the mechanism in the black box, the way the system or the thinking or the behavior internal leads to the measured external variables--that data set and its analysis. 

Now if you are a physicist, the objects you may be dealing with are fully characterized by a very small number of characteristics. But if you want to learn more, about how those characteristics are "generated," you need to go to much higher energies and much smaller distances to see inside the object you are studying. Of course, it is black boxes all the way down, or at least pretty far down. You can't interview a proton. But you can hit it with other protons, electrons, gamma rays, ... and so discover lots about what is going on inside.

What physicists now say is that they have "effective field theories." They are "effective" because there is no claim that they are ultimately the true story, but they do account for what you see at a certain scale, and you expect that if you go to a finer scale you won't throw out the effective field theory at the less fine scale. The effective field theory that we use today is called the Standard Model, and at larger scales and smaller energies, there are other effective field theories. We don't have a good clue (in terms of empirical or experimental findings) of what will be the effective field theory at smaller scales, "beyond" the Standard Model, although there is a rich landscape of speculations--none of which have any empirical support yet.

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