Philosophy of the Sciences, 1997
Lecturer: Professor Goldstein
Lecture 9: Evolutionary Theory and Creationism II
Index
1.  We have examined some of the various methodological complaints against evolutionary theory that Creationists have voiced.
2.  In his paper `So You Think You Are a Darwinian?', Philosophy 69 (1994), pp.267-277, David Stove lists what he takes to be 10 `obviously false' Darwinian beliefs.  Some of these are from modern evolutionary sociobiology.  For example:
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3.  I cite Stove's first proposition last.  It is one that is enthusiastically defended in two recent books, Richard Dawkins' River out of Eden and Daniel Dennett's, Darwin's Dangerous Idea.  (Dawkins has adapted one of the chapters of his book for an excellent article in Scientific American, November, 1995, pp.80-85).  Is the idea that life has no purpose true or, as Stove would say, `obviously false' ? 
 4.  One of the reasons why people are resistant to the idea is that human beings clearly have purposes, so how can our existence be purposeless, how can we be inhabitants of what Dawkins calls a `universe of indifference' ?  And if evolutionary theory is correct, and we are the final products of a long process that took place over millions of years, how can that process have no point   `If we are the products of natural selection, then we have been selected (chosen)', someone might say. 

5.  As Colin McGinn points out, in a review of Dennett (Times Literary Supplement, November 24, 1995) the term `selection' is misleading here.  It's not just organisms, but everything in nature that is `selected' in the sense that some things better survive the destructive forces of nature -- a mountain made of granite (McGinn's example) is less likely to be eroded by wind and water than another mountain with a sandier constitution.  We are quite happy to say that there is no purposive agency behind the existence of granite mountains.  Genes mutate; this is just a `blind', mechanical process, and some mutations render an organism less likely to destruction. 

6.  If evolution doesn't aim for anything, then it doesn't aim for complexity.  McGinn raises the interesting question of why complex forms emerge -- given that simple structures (like mountains) seem to be more robust.  Here there seems to be a fact not explained by evolutionary theory.  The theory does not predict development over time from the simpler to the more complex, but it is a fact that some presently existing organisms (such as ourselves) are extremely complex.  `The best survivor of all would be some hard little simple object that could not be broken down by the forces of nature; so why should relentless pressure towards ever greater durability [i.e. natural selection] produce such soft, friable, complex creatures as we see all around us ' Two further problems raised by McGinn: There would be a selectional advantage in a mutation which made genes responsive to changes of phenotype, so why is it that Lamarckian organisms never evolved   And how (and why) did consciousness and sentience evolve   These are problems for the theory of evolution, not refutations of it. 

7.  In Chap. 4 of Abusing Science, Kitcher examines what he calls the `substantive criticisms that purport to show that well-established facts tell against [evolutionary] theory'.  He mentions some such alleged facts on p.84: the Paluxy river bed where, so the story goes, human footprints traverse dinosaur traces; Rhodesia, where there are cave drawings said to depict dinosaurs; Glacier National Park, where the evolutionists' ordering of rock strata is `inexplicably' reversed. 
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8.  One argument of the Creationists, which perhaps echoes the feelings of outsiders too, is that when we examine such complex structures as the eye, or even when we look at the DNA molecule, it simply seems incredible, even allowing for the evolutionary time scale, that such systems could have come about from the random mutations that are the driving force behind evolutionary theory.  In addressing this point we should distinguish between what is irreducibly random (e.g. radioactive decay, according to quantum theory) and what is apparently random because determinable in principle, but not in practice.  But processes of both kinds are subject to physical and chemical law - although the former only to probabilistic laws: we should not equate irreducible randomness with pure chaos.  The point here is that if a system is purely chaotic then any future state is not even probabilistically calculable from its present state.  Thus, as Kitcher points out (pp.88-89) `Quantum chemistry explains in great detail why the elements regularly combine in just the ways that they do.  Thus there is no reason to wonder whether the order found in biochemical reactions proceeds from some mysterious source'.  The development of beautiful complex structures from random mutations is illustrated by the morph program from Dawkins' The Blind Watchmaker.

9.  Another argument that Creationists use against evolutionary theory is what we might call the argument from thermodynamics.  In particular, it is the second law of thermodynamics with which, according to the Creationists, evolutionary theory conflicts.  Following Kitcher (p.90), I state the second law as follows: `The entropy of a closed system increases with time ... i.e. if we have a thermodynamically closed system, the total amount of energy within it remains constant through time, but an increasing proportion of that energy becomes unavailable to do work.  (Alternatively, the system becomes even more disordered.)'

10.  The reason that Creationists think that the second law is in conflict with evolution is that, as they interpret it, the second law demands a trend towards disorder, randomness, whereas Darwinian theory predicts the opposite trend towards increasing complexity and organization.  In reply, we could say first, as mentioned above, that evolutionary theory doesn't predict complexity.  Further, Creationists overlook the crucial clause in the second law about the systems in question being closed.  But it should be obvious that the systems relevant in Darwinian histories are open, and where entropy decreases over time.  The reason is obvious: in all the systems of organisms and genealogies and lineages there is a constant inflow of energy from the sun: we are not dealing with closed systems.  Suppose however, that in answer to this we say that if we include the sun and the rest of the universe, then we are dealing with a closed system.  We can agree, and can grant that the entropy of this system as a whole increases.  But that tells us nothing about entropy variation at the local level (p.92), where there may be pockets of decreasing entropy.

11.  Another charge often made by the Creationists is that mutations, which are at the heart of evolutionary theory are rare and almost invariably have an adverse effect.  However, Kitcher (p.97) quotes figures to show that for homo sapiens, the number of mutations arising in one generation is 8 billion.  In other words, although it may be true that the mutation rate per locus is low (roughly one mutation per 100,000 loci), the rate per zygote is one mutation per zygote and the rate per population is of the order of one billion per population.  As to the claim that all mutations are harmful, the truth is that some mutations are harmful in some environments, but some, in the context of its immediate surroundings and of the more remote environment are advantageous.  A well-known example is the development in many species of insects of resistance to pesticides such as DDT (Kitcher, p.99).  The mechanism for this is well known: ` a change at a single locus can produce (or increase the rate of production of) enzymes that allow the pesticide to be detoxified' (p.100).

12.  The objection to evolutionary theory that I find most powerful is simply that there would not have been sufficient time for the development of the extremely complex biological systems with which we are all familiar.  We know, for example, from the drawings of the ancient Egyptians, that domestic animals haven't much changed over the last 4000 years.  How could the development of, say, the human eye have taken place in the time during which the earth has been in existence   One answer to this is that the Earth has been in existence for much longer than evolutionists usually allow. 

13.  The Creationist may well counter that, for example, the number of mutational steps needed for the evolution of the horse must be well over a million.  And if we look at the probability of these million changes occurring, given that there is a 50-50 chance of each change occurring the probability is 21000000 (same as the chance of a coin landing heads one million times in a row).  Hence (say the Creationists) the probability of a horse evolving is negligible.  But Kitcher points out (p.104) that this argument confuses apparent improbability with irreducible improbability: given the initial conditions then (assuming no uncertainties due to quantum effects) we could say that the evolution of the horse is a deterministic certainty -- just as, given the initial conditions of a deck of cards, we can say that the probability of getting dealt a given hand of 13 cards is certainty.  With no statement of the initial conditions, the probability of getting dealt that hand is about 1 in 4*1031.  Besides, it's wrong to assume, as the Creationists' calculation does assume, that these mutations occur one at a time.  Mutations are occurring all the time in populations. 
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14.  Creationists dwell on the fact that there are gaps in the fossil record.  They think that, if evolutionary theory were true, there would be fossils corresponding to all the organisms described in Darwinian histories.  The first point to be made against this is that only a tiny fraction of organisms get fossilized, so we should not expect a complete fossil record.  Second, one would expect that different organisms would have different prospects for fossilization because of the nature of their environments.  Molluscs, for example, would stand a good chance, but birds and insects are `likely to die in places where sedimentation is not occurring and where their delicate skeletons will be extremely vulnerable' (p.107).

15.  There are several cases of large-scale evolution accounted for by modern palaeontology.  Of course, Creationists will question such accounts.  Duane Gish, for example, holds that transitional forms have many structural dissimilarities.  That is true, but Gish is making too heavy a demand for evidence -- palaeontologists count themselves lucky if they can find transitional forms that are similar in just a few crucial respects.

16.  Finally, the Creationists argue that even if evolution occurred, the half-way stage, say, when a creature was burdened with an incipient wing, would confer disadvantage, so that trait would be selected against and wings would never develop.  This is a powerful objection, but even though responses to it (e.g. Kitcher, p.117 ff., R. Dawkins, The Blind Watchmaker, Chap.4.) may not be compelling, the point to be made here, surely, is that this is one of the problems on the agenda for evolutionary theory, not a devastating criticism that should make us abandon the theory and join the Creationist camp. 
Resources

There is a very useful collection of resources on this topic at http://www.phy.syr.edu/courses/modules/ORIGINS/origins.html

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