Peter Williams claimed to have found numerous logical fallacies in the writings
of Richard
Dawkins. His article has provoked this blow-by-blow response from Massimo
Pigliucci, Joshua Banta, Christen Bossu, Paula Crouse, Troy Dexter, Kerry
Hansknecht and Norris Muth.
The neo-Darwinian theory of evolution is the currently accepted
paradigm to explain the history and diversity of life on earth. Yet, ever
since the publication of
Darwin's Origin
of Species it has been under attack on a variety of grounds. Some of
these criticisms have been put forth in the philosophical arena, where
evolutionary theory has often been accused of being incoherent or logically
fallacious. Perhaps the best-known philosophical criticism of evolution has
been put forth by Karl
Popper, who once claimed that "Darwinism is not a testable scientific
theory, but a metaphysical research program" (Unended Quest, 1976).
Famously, Popper retracted his comments, once it was explained to him that
there was quite a bit more to the theory of evolution than he had understood
from a cursory examination of the subject: "I have changed my mind about
the testability and logical status of the theory of natural selection; and
I am glad to have an opportunity to make a recantation" (Dialectica 32:344-346).
In Issue 44 of Philosophy Now, Peter Williams listed a bewildering array
of eleven logical fallacies allegedly committed
by evolutionary biologist Richard Dawkins in a variety of his writings. In
what follows we reexamine each of the fallacies and comment on the extent
to which Dawkins actually commits them. This article is not meant as a defence
of Dawkins (who can surely take care of himself), but rather as a stimulating
exercise tackling the logical framework of modern evolutionary theory and
its real or perceived philosophical implications.
The Alleged Fallacies
1. Self-Contradiction - a statement that refers to and falsifies itself.
Williams quotes an open letter of Dawkins to
his daughter, in which he advises her to think for herself, determine
if a claim is being made on the basis of evidence or authority, and ask for
evidence whenever somebody claims to know the truth. The problem allegedly
is that Dawkins is conflating evidence with empirical evidence, from which
it apparently derives that Dawkins also equates knowledge with scientific
knowledge. Since the latter position is not itself based on empirical evidence,
it follows that Dawkins contradicts himself by suggesting a course of action
to his daughter that cannot actually be backed up by the very methods proposed
by Dawkins. We feel Williams is reading too much into Dawkins' advice. Dawkins
starts out by simply suggesting a sensible course of action to his daughter
whenever faced with evaluating somebody's claim to truth; he is not saying
that his advice is scientific, nor is he equating knowledge with scientific
knowledge. As for what counts as evidence, the American Heritage Dictionary
defines the latter as: "the available facts, circumstances, etc., indicating
whether or not a thing is true or valid." From this perspective, most evidence
is in fact empirical. The only exception would be
mathematical or logical reasoning, although most
people wouldn't think of this as 'evidence' so much as a 'reason 'in favour
of a certain conclusion. Finally, empirical (but not necessarily scientific)
evidence for Dawkins' statement could be brought in: one only needs to compare
the number of successful decisions that people make about, say, their finances
based on reading their horoscopes vs. following the advice of a financial
expert (if the latter is backed by empirical evidence on the performance
of various portfolios).
2. Begging the Question - the fallacy of using the conclusion of an
argument as one of the premises employed to establish that conclusion. The
problem here is that Dawkins seems to assume a naturalistic and gradualistic
explanation for the diversification of life on earth. He claims that one
can see that this must be true without stirring from one's chair, as any
other explanation can be ruled out on first principles. Williams concludes
that Dawkins must take this philosophical (not scientific) position because
he wants to exclude intelligent design a priori. Indeed, Dawkins should not
have said that one can see the truth of Darwinian evolution without stirring
from one's chair. Evolutionary biology is an empirical science, and it is
only because of more than a century and a half of investigation that we have
concluded that it is the best available explanation for the history of life
on this planet. But there are two crucial distinctions that Williams fails
to make:
a) Darwinian gradualism is only one of a panoply of naturalistic explanations
of evolution (others include Lamarekism, orthogenesis, and saltationism);
while it is indeed the one currently most widely accepted by scientists,
it is false to charge that it is the only game in town and is therefore accepted
by default.
b) Both Dawkins and Williams should make the all-important distinction between
philosophical and methodological naturalism. Philosophical naturalism, the
position that all there is to the world is natural phenomena, is indeed outside
of science proper. But what all scientists espouse is methodological naturalism,
the operational position that the best way to find a testable explanation
for a phenomenon is to assume that only natural laws are at work. While
creationists
make a big deal of this alleged 'bias', in fact all of us behave as
methodological naturalists most of the time. We are willing to bet (and this
is an empirically verifiable prediction) that the next time that Williams'
car breaks down he will not go to church and ask his preacher to fix it;
he will instead bring it to a mechanic, seeking a natural solution to the
problem. Moreover, even if the mechanic should not find any remedy, Williams
will not therefore turn to God, but will ditch the car assuming (reasonably)
that the facts are simply insufficient to find the correct natural fix, and
that he is better served by another means of transportation.
3. The False Dilemma - Two choices are given when
in actuality there are more choices possible. Williams quotes Dawkins saying
that William Paley's supernatural explanation for
the complexity of life and Charles Darwin's natural alternative are mutually
exclusive. Williams cites Michael Poole as clarifying the difference between
explanations in terms of agency and those in terms of mechanisms. The two
do not have to be in contradiction, since a particular agent (say, God) could
use a given mechanism (say, natural selection) to achieve whatever goal the
agent sets forth. We see two problems with Williams' position: first, he
equivocates on Paley. Paley was not talking about God just being the agent
determining biological complexity, he thought of God as also being the mechanism:
in other words, it is anachronistic to see Paley as a theistic evolutionist,
since he was defending the classical Christian doctrine that God created
humans and everything else directly, not through the action of natural laws.
Second, while at a more general level Poole is correct that agency and mechanism
are not necessarily mutually exclusive, 'God did it' simply does not qualify
as a scientific explanation (or, in fact, as any sort of explanation), because
it doesn't add anything to the explanatory schema.
4. The Fallacy of Equivocation - a word is used in two different contexts
and is assumed to have the same meaning in both contexts, when distinct meanings
ought to be preferred. Williams here takes Dawkins to task for shifting the
meaning of the word 'designoid', coined to explain why the appearance of
design in biological organisms is just that, an appearance. Dawkins says
that there are
natural objects
that superficially look like the result of design, for example a rock
looking a bit like the face of an American President. He claims that this
is the same sort of phenomenon that induces people to think that, say, the
vertebrate eye is designed. The problem is that the first type of 'designoid'
is obvious (i.e., people immediately realize that the face was not actually
carved), while the second is much more subtle and - Williams claims - therefore
belongs to a different category. We think Williams is partially right here:
Dawkins did choose a bad example, and for fundamentally wrong reasons. The
resemblance of a cliff outcropping to a human face is the result of entirely
random causes (wind patterns, the consistency of the rock, etc.), while
biological organisms are the outcome of two processes: mutation (which is
indeed random) and natural selection (which is anything but random). That
is why Dawkins' designoids don't cut it. However, Dawkins' fundamental point
can be rescued by simply using a better analogy. There are natural,
non-biological, processes that convey the impression of intelligent design
and provide us with a more closer parallel to evolution. For example, on
many rocky beaches, pebbles are sorted by size going from the waterline towards
the interior, in a distinctly nonrandom pattern. This is not because somebody
got all the pebbles out of the ocean, carefully weighed them, and then
constructed the beach. Rather, the pattern was created by the joint action
of two processes: the (random) action of waves and the (nonrandom) effects
of gravity.
5. The Non sequitur - Comments or claims that do not logically follow
from what has gone before, but that are presented as if they do. Williams
here leaves the field entirely to a quote from Stephen Barr, who accuses
Dawkins of attempting to defend science from allegations of being 'joyless'
and 'arid', while not recognizing that 'the public' raises those objections
to atheism, not to science itself. Apparently,
Dawkins does not seem to see the difference between science and atheism.
It is a bit difficult to make sense of what exactly the charge is here, and
especially of why this would be an example of non sequitur. We take it that
Williams' intended target of criticism is the move from modern science's
discoveries to the philosophical position of atheism. Dawkins does indeed
often state that his atheism is reinforced by the scientific understanding
of the world: the more science finds out about nature, the less room there
is for a direct intervention by supernatural entities. Now, if what Dawkins
means is that atheism is logically implied by evolution, then he is surely
wrong. On the other hand, to deduce philosophical (moral, existential, etc.)
conclusions from the best available knowledge of the world is certainly not
illogical, and seems to be the rational thing to do. The important distinction,
therefore, is between an atheism that is informed by science (which is
plausible), and one that is made logically necessary by science (which is
illogical).
6. Special Pleading (double standard) - the fallacy in which one
criticises others for falling short of particular standards and rules, while
taking oneself to be exempt, without adequately justifying that exemption.
The alleged fallacy here lies in the fact that Dawkins on the one hand rejects
'God' as an explanation, on the ground that there is no way to tell where
God himself came from, while at the same time accepts natural selection as
a valid explanation of the diversity of life on earth, even though natural
selection itself cannot
explain where
life comes from. We see three problems in William's position:
First, natural selection was never meant as a theory of
life's origins,
while 'God did it' clearly is.
Second, Dawkins would be engaging in special pleading if he had not provided
an account of how natural selection (not life) began, since the explanatory
principle parallel to 'God' here is selection, not life (life is what needs
to be explained by either 'hypothesis'). But evolutionary biology does have
an explanation for how natural selection comes into being: it happens as
soon as there is a population of self-replicating, variable, molecules. No
such explanation is available for God.
Third - once again - 'God did it' is not an explanation, but a fancy way
of admitting ignorance: an explanation is an account of mechanisms (such
as natural selection), not a label to put on the facts.
7. Wishful Thinking - a fallacy that posits a belief because it or
its consequence is desired to be true. Williams comes really close to catching
Dawkins (but not science in general) in flagrante delicto. Dawkins
is cited by Williams writing that nobody knows how life on earth originated,
but it must have been by natural causes. If Dawkins is reaching that conclusion
- as Williams alleges - because of his philosophical position of naturalism
(i.e., atheism), then he is in fact engaging in wishful thinking (though
no more than the other side when they say that life must have originated
from an act of special creation). However, there is a more moderate
interpretation of Dawkins' statement: he is just being a good scientist in
accepting as a matter of methodology that the only way to find a scientific
explanation for the origin of life is to tentatively assume that there is
one that doesn't include supernatural intervention. One may not like the
idea that science is limited to natural explanations, but it is hard to see
what sort of experiments or testable hypotheses could possibly emerge from
introducing a supernatural fiat into these matters. As an aside, we also
point out that Williams' statement that there is "a large body of scientific
evidence against" a naturalistic theory of the origin of life is simply false
(see, for example, The Emergence of Life on Earth: a Historical and Scientific
Overview. by I. Fry, Rutgers University Press, 2000.)
8. The Red Herring - A Red Herring is an irrelevant topic or premise
brought into a discussion to divert attention from the topic at hand. Usually,
the irrelevancy is subtle, so that it appears relevant to those not paying
close attention. This is really another version of the objection raised under
fallacy #6, but with a different twist. Williams claims that the real problem
of evolutionary theory is to explain the origin of catalytic proteins (enzymes),
and accuses Dawkins of distracting his readers from it by introducing natural
selection as an explanation of how enzymes became more complex beginning
from a simple molecule. Once again, evolution by natural selection is not,
and was never meant to be, a theory of life's origins. Ironically, it is
the creationists who make a red herring out of this issue, since they keep
misinterpreting the scope of evolutionary theory. Natural selection is
(demonstrably) perfectly capable of changing and improving the catalytic
actions of proteins, which is all the theory claims. On the other hand, it
is true that we still don't know how the first replicators originated; however,
what is needed for a naturalistic theory of origins is that the first replicators
were simple enough to originate randomly. This does not seem an inordinately
unlikely supposition. Lastly, it is interesting that Williams introduces
the concept of 'irreducible complexity' of proteins as if it were widely
accepted in science. It is not.
9. Straw Man Argument - a type of Red Herring that attacks a
misrepresentation of an opponent's position. That is called to hum a straw
man. It is a surprisingly common fallacy,because it is easy to misunderstand
another person's position. The incriminating passage here is one in which
Dawkins states that the difference between science and religion is that the
former is based on evidence and 'gets results', while neither apply to the
latter. Williams, curiously, takes this to be an attack on Christianity in
particular, and responds that there has been a strong Christian tradition
of valuing rationality. First, Dawkins was taking aim at religion in general,
not especially at Christianity. Second, the criticism was that religion is
not based on evidence, which is not the same as accusing religious people
of not valuing rationality. One can construe rational arguments in favour
of the existence of God, but one cannot provide any evidence to back up such
constructs. Science is an inextricable combination of rationality and evidence:
without the latter, it would not be different from logic or philosophy. Lastly,
while it is certainly true that there are great traditions of rational inquiry
within Christianity, do we need to remind Williams that the Church always
put very strict limits on such 'free inquiry'? Just think of Bruno, Copernicus
and Galileo. The scholarly tradition of the Catholic Church is surely well
represented by the Jesuits (for example, they run the Vatican astronomical
observatory in Italy), and yet it was the Jesuits who opposed Galileo and
famously refused to acknowledge the observational evidence he was providing
through his telescopes. It is hard to think of a better example of how
differently science and religion approach the relationship between rationality
and faith. ' ' Science is inherently an approach that can lead only to tentative
conclusions.
10. Ad Hominem - the fallacy of attacking the individual instead of
the argument. Dawkins, in his characteristic bluntness, likens people who
believe in God to children who believe in Santa Claus. Williams takes this
to be an ad hominem attack, and hence a logical fallacy. Williams
then goes on, somewhat curiously, to state that even children are sometimes
right, and that therefore one cannot dismiss childish beliefs altogether.
We chastise Dawkins for his language, which is sure to inflame and certain
not to gain him much sympathy. On the other hand, this hardly qualifies as
a fallacy because Dawkins is not using the belief in God = childish thinking'
equation as an argument against the existence of God. On the contrary, he
begins with the premise that God is a fairy tale and then deduces (in a perfectly
logical manner, if one accepts the premise) that believing in God is as childish
as believing in fairy tales. Of course children (or childish adults) can
be right about certain things, but Socrates (in Plato's Meno) convincingly
argued that true belief without cause is nothing to brag about.
11. Poisoning the well - a form of ad hominem attack that occurs before
the meat of an argument, biasing the audience against the opponent's side
before he can present his case. Dawkins is once again taken to task for his
language. In some of his writings, he alleges that no qualified scientist
doubts the reality of evolution, the implication being that one should not
pay attention to arguments advanced from people who do not believe in evolution,
because they are not qualified on such matters. As in other cases, we agree
with the criticism of Dawkins' language, which is clearly hyperbolic (heck,
if one searches hard enough one can find qualified scientists who doubt quantum
mechanics, by most accounts the best scientific theory of all time!). Dawkins
can indeed reasonably be taken to be 'poisoning the well' here. However,
we find Williams in turn to be rather disingenuous (and relying on an appeal
to authority, a fallacy in itself) when he quotes three allegedly qualified
and unbiased authors on his behalf: William Dembski, Jonathan Wells, and
Thomas Woodward. All three are open Christian apologists, and therefore cannot
seriously be considered to be ideologically unbiased (note that while Dawkins
is an open atheist, there is a large number of religious people from many
denominations among evolutionary scientists). Moreover, Dembski has degrees
in mathematics and philosophy, Woodward teaches theology at a fundamentalist
Christian school for ministers, and Wells has a degree in biochemistry and
molecular biology. None of them are qualified to comment on evolution for
the simple reason that their degrees are not in any of the organismal biological
sciences. One of us (Massimo Pigliucci) has a Ph.D. in Botany, which is an
organismal biological science, but he would hardly feel qualified to comment
about the reasonableness of' say, quantum mechanics. Just because one has
a Ph.D. one is not automatically qualified to pontificate on all topics,
as much as one's ego might incline one to think so.
Science, Philosophy, and the Limits of Logic
This entire discussion is based on the concept of logical
fallacies. But reasoning can be logical, and even correct, at the same
time that it is strictly speaking fallacious.
For example, one of the classical fallacies is the post hoc ergo propter
hoc (after that, therefore because of that), where one infers that the cause
of a certain effect is a particular event on the basis of the fact that the
alleged cause preceded the effect in short time (e.g., I woke up with a headache
this morning; I drunk red wine last night; ergo the wine caused the headache).
It is important to realize in what (very strict) sense post hoc ergo propter
hoc is a fallacy: if one wishes to say that it necessarily follows that if
two events are temporally close to each other, then the first one causes
the second one, this is obviously not true. We have plenty of examples of
temporal sequences the elements of which are not causally connected (e.g.,
last night it also happened to be full moon, but that very likely had nothing
to do with my headache this morning). However, it is perfectly rational to
begin the investigation into causes based on correlations, which is exactly
what science does. If I know that certain kinds of red wine (e.g., high in
sulfites) are prone to cause headaches in certain individuals, and if I
repeatedly observe that when I drink those kinds of wine I often develop
a headache the following morning, then I am logically justified in tentatively
concluding (pending further evidence) that my headaches really are caused
by high sulfites levels in red wine (and I ought to stop drinking such
concoctions). It follows from all of this that science is inherently an approach
that can lead only to tentative conclusions, while if one wishes Truth one
is limited to the realm of logic and mathematics. Philosophy occupies an
interesting middle ground between these two approaches: while a philosopher
attempts to build bullet-proof logical arguments (i.e., she aims at logical
truth of the formal kind), the premises of her reasoning can only be of two
types (Hume's famous 'fork'). Either one starts with arbitrary or unfounded
statements, in which case even logically tight reasoning leads nowhere; or
one begins with empirical observations about the world, and philosophy therefore
shares some of the limitations of science. A lot of ink and bad feelings
would be avoided if people realized that human beings (with the exception
of logicians) cannot attain Truth, but only more or less likely maybes.
© THE AUTHORS. 2004 [Philosophy Now May/June 2004]
This article was written jointly by Professor Massimo Pigliucci and the
members of his graduate class on evolutionary thinking at the University
of Tennessee, Knoxville. www. rationallyspeaking. org .
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