Monday, March 24, 2008

Evolution and scientific irrealism

Consider the following two statements:

  1. We do not have good reason to believe evolutionary theory to be true.
  2. Scientific irrealism holds.

Now claim (2) entails that science does not give us good reasons to believe propositions to be true. Moreover, the following claim is uncontroversial:

  1. All the good reasons for believing evolutionary theory to be true are scientific in nature.
Thus, (2) together with the uncontroversial (3) entails (1).

But here is an oddity about discourse in our society: There is a lot more outrage against scholars who assert (1) than against scholars who assert (2).

Is there a justification for such a differential attitude?

An explanation for the differential attitude is that those who assert (1) frequently are motivated by religious considerations, while those who assert (2) are rarely motivated by religious considerations (unless they accept occasionalism, like many Muslims, or they are led to (2) by way of (1)). But unless one has a good argument for why it is inappropriate to accept or deny a scientific claim on religious grounds, this explanation of the differential attitude is no justification. Certainly it isn't be a necessary truth that it is inappropriate to affirm or deny scientific claims on religious grounds, unless necessarily God doesn't exist: for if God exists, then he in principle could reveal facts that are of purely scientific interest, or facts of religious interest that entail facts of scientific interest.

Maybe, though, the explanation is like this. If someone asserts (1) by itself, we assume that she doesn't hold (2) (just as someone who says that Elbonians are not human is assumed to think non-Elbonians are). But in fact the only good reason for holding (1) is (2). However, simply the fact that someone believes something for a bad reason surely doesn't justify the kind of outrage that is involved here. After all, one might believe (2) for very bad reasons indeed.

Personally, I deny (2). As for (1), my views are rather complex—I accept common descent and natural selection as a major force, I accept that Behe-Dembski style arguments fail to establish Intelligent Design, but I am also convinced that we do not know that every event in the evolutionary history of every animal was naturalistic.


Anonymous said...

"As for (1), my views are rather complex—I accept common descent and natural selection as a major force,"

Rightly so.

"I accept that Behe-Dembski style arguments fail to establish Intelligent Design,

Eminently rational, sir.

"...but I am also convinced that we do not know that every event in the evolutionary history of every animal was naturalistic."

What does one say to an
Evolutionary biologist? More importantly, what is their response? Or, are you merely suggesting your inclination towards "Theistic Evolution"?

I'd love to hear you views on this, Alex. Surely, the Nobel Prize in Biology and a thousand other accolades would await you should you give strong evidence of this.

Heath White said...

I am not sure that (3) and (2) together yield (1).

We might be fictionalists about science. For example, the idea that "electric charge" flows from the positive to the negative poles of a battery, as a kind of fluid, with voltage the pressure and amperage the rate of flow, is actually totally wrong. But it does do a good job of allowing us to engineer electrical circuits.

One might have a similar attitude about science globally. Maybe von Fraassen's attitude would be somethng like this. (I'm not an expert in philosophy of science, so I'm happy to be corrected here.)

Myself, I'm a realist about science.

Alexander R Pruss said...


I wasn't claiming here that we know that some event in the evolutionary history of every animal was non-naturalistic. I was claiming a purely negative, and in no way Nobel-worthy, achievement, namely that we do not know that all events in the evolutionary history of every animal were naturalistic.

Why not? Well, I have some posts on this, but here is a really quick argument. We do not presently know it to be the case that some mutation in the lineage of, say, spiders isn't the result of an experiment by alien scientists. How on earth would we know that, at least at this point in our scientific progress? (If we knew there were no aliens, then we'd know it, I guess, but we don't know that there are no aliens.) Well, it would be odd indeed if we didn't know that some mutation in the lineage of spiders was the work of aliens, but knew that no mutation in the lineage of spiders was the work of God, angels or demons.


It seems to me that both fictionalism and van Fraassen's constructive empiricism yield (1).

Fictionalism makes evolutionary theory a useful fiction. What we learn from science, then, is basically that it is a useful fiction. But if that's what we learn from science, then we don't learn that evolutionary theory is true.

Van Fraassen believes that we do not have good science-based reason to believe in unobservables. All we have good science-based reason to do is to accept theories, which is not the same as believing them true but believing them to be empirically adequate. But the truth of neo-Darwinian evolutionary theory requires that we believe in genotypic classifications, because the genotype/phenotype distinction is central (interestingly, it may not be central for mimetic evolution). But genotypic classifications are not observable in van Fraassen's sense--to see genes requires sophisticated instruments. What we observe are phenotypic classifications. (I am assuming here that van Fraassen not only objects to unobservable entities but to unobservable classifications.) If this is right, then van Fraassen's view does not yield belief in the truth of evolutionary theory.

Nacisse said...
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Nacisse said...

people that assert (1) would be saying that evolutionary theory is bad science. people asserting (2) would not be saying evolutionary theory is bad science. on (2) evolution and other accepted scientific theory are still equal - if not true; but on (1) evolution is inferior to accepted scientific theory - because it lacks truth, which is needed unless you held (2) also... so people aren't outraged that someone thinks evolution is not true they are outraged if you think it is not science - which is a socially respectable thing (science -not truth i mean) ... irrealism seems like a sophisticated view and so is respectable (like science) while anti-evolutionism is considered Neanderthal-like - and so not something accptable in polite rational society...

Alexander R Pruss said...

One can hold, though, that a scientific theory is good science but is nonetheless false. The history of science is strewn with theories that were good science, but were false, and it wouldn't be absurd to suppose that some present-day theory is good science and false and that one might have non-scientific reason to think the theory false.

Hans Lundahl said...
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Hans Lundahl said...
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Jeremy Pierce said...

I think there's a conversational implicature of claim 1 if uttered in most contexts, i.e. that evolutionary claims stand out as unsupported by science in a way that other scientific claims don't. So I do think if someone hears 1 uttered in an ordinary context they're justified in taking it that way.

The problem you raise would be a problem for the same set of claims:

1. There's no good reason to believe Islamic terrorists were responsible for the destruction of the World Trade Center.
2. We have no good reason to believe anything and ought to be radical skeptics.

Yet I think we're justified in claiming that anyone who says 1 in most contexts is nuts.

I agree with all of your concluding stances, by the way. Behe-style arguments have (so far) failed to establish their conclusions, but I don't think it's because the form of argument is problematic; it's a standard design argument, and some design arguments are better than others.

Alexander R Pruss said...

I think anybody in normal circumstances who says 2 is even more nuts. :-)

Hans-Georg Lundahl said...

I go further: if u assume common descent (which is unnecessary if the common traits can be attributed to a common artisanal style - Mozart's Sonatas did not have sex with each other giving rise to following sonatas, though every sonata player on earth has been born by sexual acts, and in the parallel you are born to "playing only one sonata" i e being alive as only one animal/plant) some descents cannot well be attributed to natural happenings: is a new index to my whole series

I think this argument is so plausible that nothing short of divine authority (which there is not for this) can establish common descent.

Hans-Georg Lundahl said...

Reposting practically same comment as deleted above is due to remake of url.