Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site petsd.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!vax135!petsd!cjh From: cjh@petsd.UUCP (Chris Henrich) Newsgroups: net.origins Subject: Article by Brady (vandalized in "pinking shears" incident) Message-ID: <533@petsd.UUCP> Date: Tue, 4-Jun-85 20:38:40 EDT Article-I.D.: petsd.533 Posted: Tue Jun 4 20:38:40 1985 Date-Received: Thu, 6-Jun-85 03:18:36 EDT Organization: Perkin-Elmer DSG, Tinton Falls, N.J. Lines: 139 [] A while back, there was a discussion on this group about an article by Brady, in _Systematic_Zoology_, that somebody had cut out of his library's copy because he thought it would have a subversive effect on students. I looked the article up, and here is the full reference, the Abstract, and some notes on the content. Brady, R. H. (Associate Professor of Philosophy, Ramapo College, Mahwah, New Jersey 07430) Natural Selection and the Criteria By Which a Theory is Judged. Systematic Zoology 28(1979)600-621. Abstract: When recent literature on the falsifiablility of natural selection is examined, critics and defenders seem to communicate with each other very poorly. An examination of the structure of tautology and that of causal explanation provides criteria by which to examine the claims of both critics and defenders. Natural selection is free of tautology in any formulation that recognizes the causal interaction between the organism and its environment, but most recent critics have already understood this and are actually arguing that the theory is not falsifiable in its operational form. Under examination, the operational forms of the concepts of adaptation and fitness turn out to be too indeterminate to be seriously tested, for they are protected by ad hoc additions drawn from an indeterminate realm. Future knowledge may reduce the organism to a determinate system, but until such time too little is known to investigate organism-environment relations. researchers should consider whether natural selection is necessary to empiric investigation in their area, and whether it can serve the purpose for which it is applied. Here is a redaction of some notes that I took, from reading the first parts of the paper. 1. Tautology and causal explanation. A theory is supposed to be an explanation of some facts. It must add something to the facts being explained. A tautology is a theoretical-seeming statement which fails to do this. 2. The purpose of the theory [of natural selection] The theory is stated in various ways, but they come down to this: in the population of organisms making up a species, some are "fitter" than others, and it is these who contribute more to the future of that species. The meaning of "fit" in this context has been debated, and the debate seems to settle on "differential reproduction" as the criterion of fitness: a trait is "fit" if it increases the reproductive competence of organisms having that trait. Thus "increased reproduction" => "increased reproduction." The evident circularity of this statement has been remarked by many. Some biologists (Waddington, Haldane) have embraced explicitly tautological formulations of the principle of natural selection, and argued that it was nevertheless a worthwhile contribution to biology, because before Darwin nobody *realized* that it was a tautology. Brady pours gentle scorn on this debating tactic. Brady's verdict is (I think I am quoting accurately) "differential reproduction, or even differential mortality (which is closer to the original idea) has no explanatory power, but remains a datum to be explained." 3. The Hand of Nature This section is devoted to the extreme difficulty of unraveling the relations between an organism and its environment. As shown in the abstract, Brady seems to despair of event seriously trying to find anything out. 4. Miscommunications on Testability In this section, Brady samples and comments on the ongoing debate. He quotes an essay by Stephen Gould: fitter traits can be recognized by criteria of "good design." Gould's statement is flawed by a sentence in which he seems to use the theory as a basis from which to deduce factual support for the theory. Gould was replying to an essay by Tom Bethell that appeared in Harper's, February 1976. This covers much the same ground as Brady's article, and is easier reading. He predicts that biologists will quietly relinquish the theory of natural selection. In 1985, having read Mayr's _The_Growth_of_ Biological_Thought_, I don't see it happening. Brady points out that defenders and attackers of the theory of natural selection do not argue about the same issues. Defenders attempt to prove that the theory is not tautological. Attackers attempt to prove that it is not testable. Brady considers Maynard Smith's defense of the concept of fitness as being falsifiable. Smith offers an example of a trait which, if it were ever observed, would clearly not be conducive to the fitness of the organism. He suggests a deep sea fish with luminous dots on its skin; if the number was varying, but always prime, or if their distribution always matched a constellation, this would not be explicable by natural selection. Brady complains that the example is absurd; it goes against anything we know about fishes. ___________________________ I am disappointed in Brady's article. Much of his criticism of natural selection is really a criticism of biology, on these grounds: it is different from philosophy; it is difficult and complicated; you have to go out there in the (gasp) real world, and collect data. The alleged tautology of the theory of natural selection is an artifact of examining it outside of its context. Philosophers have made this mistake before. Ernst Mach, thinking about Newton's equation "F = ma", decided it was a tautology too: just a definition of F. This leaves unexplained how the "second law" can cooperate with other laws to achieve brilliant results. Similarly, I think the law of natural selection has to be considered in its context in a theory of how evolution happens. There, it is seen as allowing a small change in the genetic makeup of a population with each generation; Darwin's good idea was that this change, sufficiently prolonged, may be enough to account for big variations, even the origin of species. Brady never talks about speciation. Nor does Bethell, nor the others whom Brady cites. (In the cited passages, that is!) So he misses the interesting point. His statement that differential reproduction has no explanatory power is perverse: he ignores what the evolutionists are trying to explain. Regards, Chris -- Full-Name: Christopher J. Henrich UUCP: ..!(cornell | ariel | ukc | houxz)!vax135!petsd!cjh US Mail: MS 313; Perkin-Elmer; 106 Apple St; Tinton Falls, NJ 07724 Phone: (201) 758-7288