Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site cvl.UUCP Path: utzoo!linus!decvax!ittvax!dcdwest!sdcsvax!sdcrdcf!hplabs!hao!seismo!umcp-cs!cvl!nelson From: nelson@cvl.UUCP (Randal Nelson) Newsgroups: net.origins Subject: Re: margaritas ante procos -- on the rocks, please Message-ID: <1389@cvl.UUCP> Date: Sat, 29-Sep-84 02:51:33 EDT Article-I.D.: cvl.1389 Posted: Sat Sep 29 02:51:33 1984 Date-Received: Tue, 2-Oct-84 03:21:30 EDT References: <186@uf-csg.UUCP> <338@uwmacc.UUCP> Organization: Computer Vision Lab, U. of Maryland Lines: 72 > What is your proper definition of "theory"? I would assume from > your comments that it should include a falsifiability criterion. > Very well. What is the falsifiability test for (any brand of) > evolution? There are a number of conceivable situations which would serve to falsify, or at least cast grave doubts upon, any evolutionary theory. Some of these are: 1) The absence of any physical mechanism by which changes could be passed from generation to generation. At the present time, we are fairly certain that this mechanism is based on the self-replicating properties of DNA and related structures, but at the time at which evolutionary theories were advanced, such a mechanism was a prediction of the theories (though since borne out). 2) A complete lack of (non-lethal) mutations. Again, the presence of viable mutations is a prediction which seems to have been borne out. Mutation appears to be a common event in all living systems, and although most mutations are invisible or lethal, this is not always the case. The above are examples of falsifiability criteria which now appear to be contrary to established fact; however, this has only become evident by the dint of much effort, after an initial prediction had been made. At the time at which evolutionary theories were being propounded however, the tests represented open questions. It is also true that both the above situations represent negative claims of the form "If X is never found, then the the theory is false" (i.e. the theory predicts that X will be found). It is easy to show that such a statement can not falsify a theory (simply by finding X.) It is far more difficult to argue convincingly that simply because X has not yet been found, that we will never find it. We could simply be looking in the wrong place. A theory is much stronger if it also makes statements of the form "If Y is ever found then the theory is false". The theories of phsysics for example, make predictions of both forms: for instance, the existance of the nuetrino was predicted, (and eventually confirmed) and no violation of the law of conservation of energy has ever been observed. In short, a usable theory should make predictions both of the form (A) "X will be found", and (B) "Y will not be found". Both falsifiable conditions 1 and 2 above are the result of type A predictions. However there is no shortage of type B predictions for evolutionary theories. The following conditions, if met would cast grave doubts on the theories' basic validity. 3) The discovery of planets which are earthlike in terms of temperature, atmosphere and presence of water but on which no life exists. This is a test which a great number of investigators would like very much to make, because one of the most significant predictions of the evolutionary theories, is that under appropriate conditions, life will invariably arise. Unfortunately it does not appear likely that we will have any evidence one way or the other in the near future since the likely places to look are terribly far away. 4) The verifiable, spontaneous appearance of new life forms. This does not include rains of frogs, inexplicable infestations of vermin, the discovery of a new species of beetle in the Amazon rain forest, or even the Bibical account of the creation. Randal Nelson,(nelson@cvl) Center for Automation Research University of Maryland