Re: [asa] Theory of gravity

Merv,
    I'm a bit uncomfortable with the view that a law is primarily a theory that has passed more tests. George said it better when he pointed out that these labels are used somewhat loosely and we don't derive as much significance from the label as we do the content and how it was derived and what it means. In very general terms, I would think that "laws" are more closely related to "equations" than to "theories." Specifically, "laws" tend to be the equations that are more useful and fundamental--the starting point for the derivation of equations that apply in specific situations. We say "Newton's laws of motion" but "Schrodinger's equation" even though the latter is more rigorous and passes more tests. We say "laws of thermodynamics" or "Fick's laws of diffusion" rather than "theory" because they are equations that can be applied in specific situations to calculate specific effects. A theory would tend to encompass the bigger picture of why these equations hold as in "diffusion theory." We say "theory of relativity" and the "relativistic equations" or "Einstein's equations" and mean slightly different things with it. The theory certainly includes the equations but tends to refer to the reasoning process behind it. Hence "quantum theory" and the "Dirac equations."
    Of course, the use of the word "theory" as a "tentative hypothesis postulated for possible future verification" is a legitimate use of the word but it is by no means the only use and it is wrong to attribute this meaning to situations where the meaning is closer to that in my previous paragraph. In other words, the use of the term "theory" by itself provides no clue to the degree of verification or validity of its contents.
     In this sense, the phrase "law of evolution" would make no sense. Those who would use this phrase as a means of connoting more validity than the "theory of evolution" are making the same error in usage. The true laws underlying evolution turn out to be the laws of thermodynamics and quantum mechanics but we don't know anywhere near enough of the specific energy levels and multi-dimensional potential energy landscape to do much with them. When the day comes that we can write the Hamiltonian for the entire human genome and solve Schrodinger's equation rigorously for an arbitrary environment, then perhaps we can start talking about calculating probabilities. I don't think that will be next year.

    Randy

    
  ----- Original Message -----
  From: Merv
  To: asa@calvin.edu
  Sent: Wednesday, November 21, 2007 8:18 AM
  Subject: Re: [asa] Theory of gravity

  One way that I have put it to my science students is that a law is like a theory that has withstood the tests of time; which is not the same as calling something "proven" (a term more apropos to mathematics than science), but it just shows the highest degree of confidence that science confers by means of a label. This is more simplistic than the nuances into which you delve below. But I would venture that those who want to refer to the "law" of evolution (and I have heard this expressed), do so with more political / metaphysical motivation than other more purely scientific motives. Scientists themselves, I think, are not so caught up in these attempts at hard categorization because they are aware of the constant flux between those two concepts as you allude to. And the "only a theory" retort against evolution also betrays a lack of awareness about that same flux, and how highly regarded a "theory" can actually be.

  --Merv

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Received on Wed Nov 21 17:09:23 2007