Friday, September 23, 2011

A Brief Look at Logical Fallacies
by Robert Gerow

defeatingdarwin† In Defeating Darwinism By Opening Minds (InterVarsity Press, 1997), an excellent basic-level guide to recognizing the flaws of Neo-Darwinian evolution, author Phillip E. Johnson highlights several critical thinking tips that every person should employ. Johnson is a legal scholar by trade, and since the publishing of his controversial book Darwin on Trial (InterVarsity Press, 1991), he has debated many top evolutionary thinkers in print and before audiences. Thus, he is all too familiar with the fallacious reasoning that Darwin’s apologists regularly engage in, and dedicates chapter three of Defeating Darwinism to the task of exposing said reasoning through what he calls “baloney detecting” (a term borrowed from the late astronomer Carl Sagan).1 The well-tuned baloney detector recognizes a number of invalid argument strategies, and I’d like to describe a few of them to you in summarized form. I highly recommend that you read either of the two books mentioned above (or both!) if you get the chance.

(Note: the following do not by any means apply only to the subject of evolution. People on all sides of all issues commit logical errors from time to time; this guide attempts to show how certain errors tend to manifest in this specific topic.)

1. Selective Use of Evidence:

As Johnson puts it, “There is a whole lot of evidence out there, and even a false theory is likely to be supported by some of it.”2 Don’t be intimidated by the fact that, viewed through Darwin-colored glasses, some scientific findings (such as the few fossils considered to be transitional forms) seem to support the theory; it’s almost impossible that this not be the case! Johnson recommends questions such as, “Does the fossil evidence, considered as a whole and without bias, tend to confirm the predictions of Darwinian theory?”3 I submit that, judging by the small number of fossils found that allegedly support common descent after over 150 years of searching, the answer is no.

2. Appeals to Authority:

As all students of logic recognize, “Nothing is true just because some big shot says it is true.”4 To advance a proposition solely on the basis of its friends in high places is to commit the logical fallacy of “appeal to authority,” or, when in Rome, Argumentum ad Verecundiam5 (remember this phrase and look smart later…). No matter how many leading scientists believe that unguided evolution produced all life, the proposition is only supported by science if it is the best inference from the raw empirical data. The point is not to be overly skeptical of all claims of science, but to recognize that scientists are biased humans too, and it is evidence, not acclaim, that dictates truth.


3. Ad Hominem Arguments:

Johnson explains that these sorts of arguments “attack the person making the argument instead of the argument itself.”6 This method is constantly employed by abrasive evolutionary thinkers such as Richard Dawkins, who seems to find no end of satisfaction in mocking anyone who rejects his favorite theory (just read anything he’s written that touches on the evolution/ID controversy, and I guarantee he’ll insult someone). Like the last bit of baloney (and all of them, really), this one is another attempt to direct attention away from the actual evidence, which can be a pretty good indicator that the one who tries it is in a tight spot (or at least has no substantive rebuttal to make). Don’t let such distractions get you off track.


4. Straw Man Arguments

If you don’t feel equipped to take someone’s argument head on, you can always construct a less-imposing model of the argument and go after that instead. This is called the “straw-man” fallacy, and as Johnson notes, “Creationists are particularly vulnerable to this kind of attack.”7 An example might be:
C: I don’t think there’s very solid evidence that random mutation provides complex new genetic information.
D: Oh, so anything scientists don’t fully understand yet automatically must have been done directly by God?
This scenario occurs constantly in various forms, and is very frustrating. Make sure that each party in any debate is addressing the actual points of the other.

5. Begging the Question

This one occurs when a person’s argument “assumes the answer to the point that is in dispute.”8 Another (more common) term for this is “circular reasoning.” It’s like saying “Darwinism is true because it’s true,” but in a more subtle way. For example, consider the statement “Obviously humans evolved from lower hominids by accumulating random mutations, because there’s no other way they could have evolved.” Maybe they didn’t evolve from lower hominids at all! But only the evidence can tell us that, not deck-stacking rhetorical tricks. Make sure the conclusion is supported by the evidence, rather than being inserted into it beforehand.

A few more are covered in the chapter, but I’m going to stop for now. Be sure to check out Johnson’s books, and for a lot more information on topics such as evolution vs. creation, take a look at the youth apologetics classes we offer. If you have any apologetics questions to which you’d like a moderately researched answer of moderate length, email me at, and I’ll try to get back to you moderately quickly (I might even post about it). Also, feel free to comment!

Thanks for reading, and God bless!

1Phillip E. Johnson, Defeating Darwinism by Opening Minds, InterVarsity Press, Downers Grove, IL, p. 37, 1997
2Ibid., p. 38
3Ibid., p. 39
4Ibid., p. 39
5Norman L. Geisler and Ronald M. Brooks, Come, Let Us Reason, Baker Books, Grand Rapids, MI, p. 98, 1990
6Phillip E. Johnson, Defeating Darwinism by Opening Minds, InterVarsity Press, Downers Grove, IL, p. 40, 1997
7Ibid., p. 41
8Ibid., p. 42

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