Date: Tue Mar 22 1994 04:24:22 Subj: Theories and science EVOLUTION

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Date: Tue Mar 22 1994 04:24:22 From: Rob Fargher Subj: Theories and science EVOLUTION ------------------------------- -=> Quoting Tom Clayton to Trent Hall <=- TH> suggested explanation a proof? No, merely a theory that perhaps proves TC> Obviously a "suggested explanation" is not a proof. It is a theory, The above exchange exemplifies the complete misuse of the term theory in common parlance. As your former president, Ronald Reagan stated "Well, evolution is just a theory" and demonstrated that such misconceptions pervade the whole of society (though I'm not sure just what stratum he represents!). The whole structure of scientific explanations is strictly hierarchical and the ranking of any individual phenomenological exegesis depends upon how much confidence we have in it. Science, if it is nothing else, is a method for determining, in an unbiased manner just how much confidence we can have that a given explanation is correct. Secondly, the ranking depends upon how much evidential support there exists for a given accounting and the explanatory power it has to encompass known facts better than competing explanations. With that as a prelude, here is my taxonomy of scientific exegesis: 1) Wild Assed Guess. This is an inductive leap of faith and is generally the starting point. Usually the product of an individual, a wild assed guess is the product of idea generation and intuition. There is no direct evidential support for a wild assed guess as it is invoked to explain an existing situation and has not yet been subjected to testing by experimentation. 2) Beer Parlour Hypothesis. Similar to a wild assed guess, a beer parlour hypothesis is the outcome of a group of individuals in a very relaxed informal environment where ones reputation is not on the line. Fruitful locations are bars close to universities, hotel lounges at a scientific conference, and campfires while out in the field. Again, a beer parlour hypothesis does not have direct evidential support but having been exposed to the immediate challenge of competent critics (other grad students, supervisors or ones peers) seated around the same bar table, they are useful guides to the work to be done in the lab in the next week. Both of the above are prolific idea generators. 3) Working hypothesis. A more respectable ranking, a working hypothesis is the local paradigm that one has to understand a phenomenon. It must have explanatory power to cover the known facts and make testable predictions that directly aid in the design of experiments. Perhaps a few experiments have been done that provide support in favour of ones working hypothesis but it has not yet been conclusively shown to be a better explanation of known phenonmena than competing hypotheses. Working hypotheses are frequently discarded as the winnowing process of testing and falsification shows them to be inadequate. Many people really equate theory with working hypothesis, as in "I have a theory to explain that" or "Well, evolution is just a theory." 4) Hypothesis. A hypothesis differs from a working hypothesis in that it has extensive evidential support, that attempts to falsify it have failed. Thus we have greater confidence that the explanation of known facts provided by the hypothesis is approaching an accurate model of reality. Generally, a hypothesis has a known flaw: either it is not a significantly better explanation of competing hypotheses or one of the predictions made by the hypothesis is seen to be inaccurate. A true hypothesis has a lofty ranking and is a respectable beast because of its evidential support. 5) Theory. A theory is more than a grown-up hypothesis. It has been subjected to large scale testing and challenges and has passed every one with flying colours. We have great confidence in a true theory, believing it to be more likely correct than wrong. There are no known flaws, all predictions have been shown accurate and it is a significantly better explanation for nature (or at least the phenomenon under consideration) than any rivals. True theories are very valuable critters; they provide a paradigm or a conceptual framework for the approach to solving new problems (ie. design assistance). They also provide powerful problem solving strategies (ie. methods to be used in testing and interpretory power in assessing the results of testing). 6) Law. A scientific law is conceptually different from a scientific theory. A law is a description (not an explanation) of universal behaviour. We have no idea why laws exist, other than that is the way the universe is built. Thus, the laws of physics just are. It is expected (hoped) that as theory advances and becomes more and more an accurate model of reality that the behaviour that a law describes becomes an obvious consequence or prediction of theory. I hope the above helps to clarify for people just what scientists mean when they talk about the Theory of Evolution. In common parlance, a theory is generally equated to, at best, a working hypothesis and is something that can be freely discarded as lacking evidential support wheras in reality, a theory is an extremely well tested model of reality, one far more likely to be correct than incorrect (but _always_ subject to being falsified). Cheers, Rob


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