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Re: [Phys-l] Global Evolution as fact



At 14:28 -0500 01/10/2011, Kyle Forinash wrote:

Having co-taught a course in philosophy of science I can tell you that
the concept of a "fact" is not well defined in science because
scientific "facts" change over time. Some scientists (e.g. Aristotle)
once were absolutely sure the earth was at the center of the universe
(and they had perfectly good reasons to think so). A second problem is
we often teach "facts" that aren't really true (e.g. Newton's laws,
Snell's law, etc.). Just about any set of definitions that attempt to
distinguish between fact, law and theory either can be shown to be
inconsistent or flies against common usage (Kepler's laws are not true
but the theory of relativity is).

So what to do if there are no "true facts" (in some set of absolute
sense) in science? Here are two ideas that seem to work: 1. Often we are
justified in believing certain things to be true, given the evidence we
have at hand (at least until there is counter evidence, at which point
we are justified and perfectly rational in changing our mind). The
overwhelming evidence for evolution and global warming makes it rational
to accept as true or factual. You may decide evolution or climate
change needs more work, you may not believe it in the same way that you
might believe God exists but to be scientific, you really should accept
it as a fact (always continent on the possibility of new data!). 2.
Often it is rational to accept something as "true for the purpose of".
Newton's laws are true for the purpose of building bridges.

Historically science has hardly ever rejected a theory until a better
explanation came along. I seriously doubt that evolution or global
warming will be dumped until a more comprehensive theory is found.

Why must we continue to build the wal between science and the general public by allowing language to be used differently by the two groups. It is a major impediment to science education at least. It is quite possible for a student to read a paragraph in his or her science text, thinking that he or she understands every word, but finding that the paragraph seems to be gibberish. Often it is because many of the words in the paragraph are ordinary, everyday words that have been used in a different way by the author, so, while the student thinks the words are clear, in fact the meanings have been changed so that the paragraph now makes no sense to someone who has a different idea of what some key words mean.

This goes on on both sides of the wall. Good scientific words have been adopted by the general public with a different meaning, "theory" being one of them. On the other side, scientists have taken over some ordinary words and altered their meaning in the scientific context ("specific", and in "specific gravity" being one of them). This is not an insignificant impediment to the new learner.

Scientists also often use language metaphorically that has a non-metaphoric meaning among the general public. I refer here to the habit we all have, in an effort to condense some of the complex ideas of science, of personifying non-animate matter, implying that we are attributing some teleologic purpose to it. When the say something like "evolution selects . . ." we know that we are not implying a purposeful motive to the inanimate concept of evolution, but that nicety is lost to the non-scientist. When we, in arguing that, for example, all electrons are the same, the say something like "the electron doesn't care where it finds itself" we are implying some form of conscience to the electron, which surely must puzzle the intelligent non-scientist.

The is a group of the climate change deniers who argue that the second law of thermodynamics makes the greenhouse effect impossible (or if it is possible, it is a violation of the second law, bringing the whole of thermodynamics into question. One of the things they assert is that a cooler object does not radiate to a warmer object. I am not interested in the technical results of this idea, only in the clear misunderstanding that this language implies. The assumption is that the cooler body somehow senses the presence of the warmer one and therefore directs none of it outgoing radiation in that direction. I obtained a copy of the peer-reviewed journal article discussed on this lest a while back and found that the authors actually seem to believe this nonsense. Neither body has any capability of detecting the other, and radiates according to its temperature in what ever directions it is capable of radiation. If there is another body at a different temperature nearby both will radiate as if the other didn't exist, but each of the two sets of radiation will partially cancel the other, allowing the net energy flow to occur in complete compliance with the second law. But this gross mischaracterization of thermodynamics by presumably qualified scientists who seem to believe that objects have built in detecting devices for other objects has caught on among the denier community and has given them, finally, a "peer reviewed" article that supports their viewpoint.

Just more loose talk by scientists taken literally by the general public. In many respects, we have only ourselves to blame if the public distrusts scientists. We really need to do two things: 1) don't talk down to the general public when we try to explain scientific phenomena; and 2) say what we mean in words that are precisely understood by both parties.

"Fact" seems to be another word that is being used in different senses by different people. Facts are data--that is direct observations. While they may be in error, or, by the nature of measurement, not precise, they tend not to change with time (except to the extent that they may be corrected or refuted by better future observations). The use those facts are put to are not facts, they are the stuff of which theories are built. Newtonian mechanics is a theory, it is not completely accurate, but it is certainly accurate enough for many purposes. We don't need relativity or quantum mechanics to build a building, or navigate the solar system, but when the accuracy is needed, as with, for example, the GPS system, or to explain the anomalous precession of the orbit of Mercury, then the theory of relativity is invoked. But the fact that Newton's gravity is accurate enough for the vast majority of purposes does not make it a fact. What is does is make it a vary good, but not perfect theory.

We should not make the mistake of conflating facts, which in general do not change with time except tot he extent that the humans who gather the facts are imperfect beings who sometimes make mistakes or don't measure as well as we would like to, with laws or theories which are built upon facts and enable us to predict that observations can be made in the future, or which enable us to understand why some previously puzzling observations were made in the past. To do so is to tell the public that all facts are temporal and will change in the future, as, so far have all theories, to more or less extent.

That is the philosophy of science that we need to be teaching to our students.

In fact, we probably need to quit talking about facts and theories altogether, and start talking about models and observations. We know what those words mean.

Hugh
--

Hugh Haskell
mailto:hugh@ieer.org
mailto:haskellh@verizon.net

It isn't easy being green.

--Kermit Lagrenouille