Circular Macroevolution

I am grateful to Paul Braterman for helping me to notice just how circular a particular objection to evolution is.

Some science deniers accept microevolution, the sort that can be experimentally studied in laboratories, but will reject macroevolution, saying that macroevolution has never been observed.

The problem with this is that macroevolution is defined as the sort of evolutionary change that occurs over longer periods of time than are observable.

If you define macroevolution as that which occurs over periods too long to observe, and then object that it cannot occur since it has never been observed, you have offered a circular argument.

 

  • Stephen

    The introductory “Apologetics” class at my former seminary was an introduction to the Validity of Circular Reasoning. Oh, and the best part…that is not my redescription of the class, the professor explicitly taught the validity of circular reasoning.

  • http://www.about.me/jbchapp JB Chappell

    1. This really isn’t circular
    2. I don’t know of any creationist who would define “macroevolution” in such a way
    3. It is hardly wrong to point out that something is an inference, not an observation.
    4. It *IS* wrong to pretend as if that fact precludes it from being true and/or scientific. After all, the same people who would make such an objection are the same who would believe in all sorts of unobservable things (and, really, who doesn’t?).

    • http://www.patheos.com/blogs/exploringourmatrix/ James F. McGrath

      If the definition of the word “macroevolution” includes the fact that change is involved which takes longer than a human lifetime (and it certainly does, implicitly if not explicitly), then complaining that we have never seen macroevolution occur before our eyes is indeed circular, a mere restatement of the definition.

    • beau_quilter

      When theory makes observable predictions, it is far more than inference. The ability to access the genome of living species is still a science in it’s youth; and yet every genome we have sequenced thus far confirms the predictions of evolution.

  • David Evans

    I see this as a variant of the “Were you there?” argument.

    “Humans and apes evolved from a common ancestor.”
    “Were you there?”
    (retires, defeated)

    Similarly
    “The Himalayas were formed by the collision of two tectonic plates.”
    “Were you there?”
    (ditto)

    The correct answer in both cases is “No, but we can infer that it happened by looking at the rates of processes going on in the present, for which we are there.”

  • beau_quilter

    My problem with the “were you there” approach of creationists, and the argument that evolution is “full of gaps”, is that creationists are completely inconsistent in applying this “problem” to other fields of science. If a “gap” means not yet knowing how every possible example has followed the theory, then every scientific law and theory has gaps: Newton’s laws of motion, Einstein’s theory of relativity, Kepler’s laws of planetary motion, Hubble’s law of cosmic expansion, the theory of molecular bonds, etc.

    All theories have gaps, in that we do not have (and could not possibly have) detailed historical accounts of how each of these theories have worked for every system in the universe. The test for the success of the theory is how well it accounts for (and predicts) those systems we ARE able to observe. By this test, the theory of evolution has as good, or better, a track record than any of the other laws or theories I’ve listed.

    • http://www.patheos.com/blogs/exploringourmatrix/ James F. McGrath

      They certainly don’t apply the “were you there” response to things in the Bible!

  • arcseconds

    It’s not circular.

    What the argument here is scepticism about things that can’t be directly observed (because they’re in the past or they take too long to be monitored). We might disagree about whether this scepticism is warranted, but it’s not a logically fallacious suggestion.

    Even if the definition of ‘macroevolution’ is something along the lines of what you say it is, having terminology to distinguish a process that can be directly observed from a similar process that can’t be seems unproblematic, assuming you think the distinction can be drawn and it’s an important one to make.

    Scientists and philosophers of science have often in the past drawn a similar distinction between ‘observable entities’ and ‘unobservable entities’. I think the distinction is problematic, but it’s not plain circular, and there are certainly cases where the distinction can apply — particles that leave traces in cloud chambers versus those that don’t, for example.

    I don’t think that is what ‘macroevolution’ means, though. I think it means ‘evolution involving change of such a degree one kind has changed into another’, as opposed to microevolution which is ‘evolution involving small modifications within a kind’, where ‘kind’ could be a species if you’re that sort of creationist.

    • http://www.patheos.com/blogs/exploringourmatrix/ James F. McGrath

      But given the pace at which macroevolution proceeds, isn’t it implicit in any definition that it takes longer than one human lifetime? And so isn’t objecting to a process that moves that slowly on the basis of not observing it during a single human lifetime fundamentally illogical?

      • arcseconds

        No, just because something happens to always be the case doesn’t mean it’s implicit in the definition of anything!

        The universe is (as far as we can see) always expanding, but it’s not implicit in the definition of universe that it be always expanding.

        Young earth creationists don’t say that macroevolution couldn’t have occurred because it takes more than one human lifetime to observe. Their point here is a sceptical one: we can’t know that this happened (because we weren’t there to see it). It may have done, but we’re not (supposedly) in a position to tell.

        They have other arguments that macroevolution couldn’t have happened:

        1) an argument from incredulity. They apparently really can’t believe or understand that one kind could turn into another.

        2) an argument to the effect that the proposed mechanism (natural selection) couldn’t account for this.

        I think they’re prepared to allow natural selection can do ‘superficial’ things like change skin colour or develop antibiotic resistance, but not kind-changing things.

        One thing that probably stands behind both of these arguments is that kinds are the result of design: God’s gone to His draughtboard and drawn up the plans for a segmented worm, and after designing it implements it by miraciling it into existence, and after that it doesn’t make any sense for it to change into a mammal, or even a crustacean, any more than it makes any sense for a car tire over time change into a toaster-oven.

        Also, as I’ve mentioned before, they’re really inclined to see the world in terms of rigid categories: male/female; has a soul/doesn’t have a soul; is a person / is a thing; saved/unsaved. People who transcend in some way their male/female categories really disturb them, and I think they find the notion of lizards changing into birds similarly disturbing.

        Creations of course want to deny that the past is anything like mainstream scientists think it to be. The ‘where you there’ scepticism is generally applied to all such past knowledge. It’s not something specific about evolution.

        • http://www.patheos.com/blogs/exploringourmatrix/ James F. McGrath

          Well, they don’t apply the “were you there?” skepticism to things they want to believe, such as many things in the Bible.

          • arcseconds

            Yup.

            They think the ‘where you there?’ argument is really good, because in their view no-one can be absolutely certain about what happened long before they were born, especially not as a result of handwaving and ponitificating about layers in rocks and putative biological processes which haven’t been observed.

            Whereas they have a first-hand account written by an impeccable eyewitness.

          • Gandolf

            When it comes down to genetics used for DNA criminal profiling. To help convict someone of murder or raping a family member .

            Very few tend to deny it.

            Yet they do tend to deny genetics used for DNA profiling. That may point toward patterns of macro evolution happening within common ancestry.

    • beau_quilter

      The real circular argument (which, incidentally, I think characterizes YE creationists, but not James’ sort of liberal Christianity):

      I believe in the Bible because I believe in God because I believe in the Bible because I believe in God because …


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