Answering a Creationist Comment

A commenter named Wagner posted a reply to my comments on an older thread at In the Agora, which I just noticed. The reply deals with evolution and creationism and I didn't want it to get lost, so I'm moving it up here and responding. I also think it's a good idea to give this comment its own space because it's an excellent example of the types of arguments typical of creationists. It contains lots of conclusionary rhetoric and what little substance it contains - actual discussion of the evidence - is highly inaccurate. But first, the conclusionary rhetoric:

To quote one of your own, evolutionsts have deluded themselves into thinking that they are scoring points against opponents who are simply playing a different game.

Completely meaningless and gratuitious and without any information content at all.

The difference is not in the science. It's in the context within which you interpret the science. Whether its proponents like to admit it or not, evolution rests on presuppositions and conclusions that are fundamentally flawed.

The first part makes little sense. Science is interpretation. Perhaps he means "evidence" or "data" rather than "science". The second part is, again, conclusionary rhetoric without any detail or support. The one example he gives of an evolutionary "presupposition" that is flawed is, as we shall see momentarily, quite inaccurate.

Teaching either intelligent design or evolution as the backstory for science is poor policy because, even though intelligent design at least recognizes that the presence of order and design implies the existence of an orderer or a designer, neither side can establish that its thesis is correct. [And, no, this isn't simply an example of "Brayton's relativism" (identified as such to avoid confusion with real relativism).]

As a result, scientific, intellectual and philosophical honesty and integrity demand that you present not only the facts and results that support your thesis but also those that differ from your thesis so that the exploration of the world we live in and the search for meaning don't get muddied by erroneous presuppositions. In other words, if you're going to teach anything, you have to teach both.

The first paragraph doesn't appear to express any coherent thought at all. I have no idea what teaching ID or evolution as "the backstory of science" means. Evolution is a scientific theory, a result of the application of science, not a "backstory" for science. And I have no idea what he means by "Brayton's relativism", or "real relativism" for that matter, but his argument is a good example of a common creationist misconception about the nature of proof and certainty. His argument is that since neither side can be "proven", you must teach both sides. But this wraps up several logical fallacies into a single statement. First, it's a false dichotomy - there are in fact hundreds of possible explanations for any given phenomenon, and using this simplistic "if it's not proven, you must teach them all" standard, we'd have to teach every single one of them.

Second, and most importantly, it presumes that we are dealing with deductive rather than inductive reasoning. If you're dealing with deductive reasoning, you can deal with proof and a simple either/or certainty - if the premises of the syllogism are true, the conclusion will be true. But most scientific work is inductive, not deductive, and the notion that there are only two categories - "proven true" and "as plausible as any other explanation" is simply nonsense. Certainty is not a simple ladder leading from "unproven" to "proven", especially if one is going to claim that all ideas that are in the "unproven" category are equally valid or plausible. Certainty is a continuum. The longer a scientific theory resists disproof and continues to explain data well, the more certain we are that it is true. When it explains a wide range of data from a dozen distinct fields of inquiry well, the certainty moves even higher.

Under Wagner's reasoning, if an idea is not proven then all alternative explanations, no matter how fanciful, have to be taught along with it. But let's look at a few other examples of how this would apply and see where it gets us. No one today doubts the theory of gravity, but in fact our scientific understanding of gravity is quite lacking. Sure, we can make accurate predictions with it, but we don't even know what gravity is - a force? A wave function? Quantum theories of gravity and relativistic theories of gravity, I am told by my physicist friends, are still quite controversial among specialists. Must we, then, also teach that the planets might stay in their orbits because angels push them around that way?

Likewise, heliocentricity, while accepted by all but a tiny minority of astronomers and cosmologists, still has its detractors. The geocentrists have their own institute, just like the IDers, and they make many of the same arguments against heliocentricity - that it was motivated by a desire to do away with God, that it has resulted in more support for "materialism" and taken man out of his rightful place at the center of God's creation, and so forth. And they have scientists with genuine credentials too. Must we then teach that as well? By Wagner's reasoning, we must. After all, we can't "prove" that the Earth is not the center of the universe because the geocentrists have come up with explanations for all the apparent evidence we think we see.

One could go on and on. Must we teach alternatives to the germ theory of disease? After all, it's trivially simple to find lots and lots of places where modern medicine has failed to explain or treat someone's illness. Why, those godless heathens in the medical profession are so stuck in their materialistic presuppositions that they rule out all supernatural explanations a priori. What if disease is really sent by God as punishment, or to test our faith? Or what if it's sent by Satan to destroy our faith? Or a combination of both, like Job? Must we teach supernatural alternatives to meteorology and seismology as well? I know these examples sound absurd, and that is exactly my point. The logic behind them is the same as the argument above, and they are absurd, but that is where the consistent application of Wagner's argument takes us.

Just in case somebody missed it, I am a creationist - I think it presents the best, most logical, most internally consistent, and most coherent explanation for the existence of life. I think we're going to be somewhat surprised at how old the earth really is, on both sides, although I do not believe the data is consistent with an age of "billions and billions" of years old.

But as we shall see, Wagner's understanding of the data on the age of the earth is seriously lacking.

For example, so many people have accepted the basic conclusion that the earth is 4.3 billion years old, even though scientists agree that they have not found a way to determine the exact age of the Earth directly from Earth rocks because the Earth's oldest rocks have been recycled and destroyed by the process of plate tectonics. (from the U.S. Geologic Service)

Further, the basis for the calculation is old, presumed single-stage leads coupled with the Pb ratios in troilite from iron meteorites, specifically the Canyon Diablo meteorite. In addition, mineral grains (zircon) with U-Pb ages of 4.4 Ga have recently been reported from sedimentary rocks in west-central Australia. (also from the U.S. Geologic Service)

Okay, now we're getting into the actual evidence. Unfortunately, almost everything he says here is false. First, the age of the earth has long been settled at ~4.55 billion years old, not 4.3 billion. Second, plate tectonics has very little effect on the ability of geologists to test basement rock samples and use them for radiometric dating. Volcanism can have a large effect on the dating of any particular sample, of course, because when a rock melts it will release the gasses trapped in the rock matrix and therefore restart the atomic clock. But if there has been a melting after it initially formed, that would make a given rock sample older than it tests so it only hurts Wagner's argument. And even in cases where volcanism has taken place, there are often older chunks of unmelted rock, called xenolithic inclusions, that can be identified within a lava flow and dated accurately. Geologists do this quite regularly. And it should be pointed out that one of the reasons why geologists like to use meteorites to test the age of the earth is that they are not geologically active - no tectonics or volcanism at work - and therefore the samples are undisturbed. Since meteorites would have formed in the same time frame that the planets formed in our solar system, and from the same forces at work, they are an ideal way to test the age of the earth.

Wagner then seems to imply that our calculation for the age of the earth is based upon a single meteorite, the Canyon Diablo meteorite. That was true in 1956; it was not true for much longer. Patterson used radiometric dating, specifically U-Pb dating, to determine the age of the Canyon Diablo meteorite to in the early 1950s and that date was 4.55 billion years old. That has been the accepted age ever since, not because of this single test but because since that time we have used a wide variety of radiometric techniques to test a wide variety of terrestrial and non-terrestrial objects (meteorites) and they have all come up with essentially the same date. And we're talking about hundreds of such tests, not just one. Chris Stassen has an excellent FAQ on the age of the earth at the TalkOrigins archive and he lists all of the various samples that have been tested, what technique was used, and what the results were. And if you plot all of the data out, you get a perfect isochron, which is a crucial test of the validity of this method. When you have hundreds of concordant dates from hundreds of different objects, all agreeing within a very small percentage of error, and they plot out a perfect line on a graph, there's simply no way to explain that away.

However, all of those assumptions are based on theories postulated between the years of 1785 and 1800 by James Hutton and William Smith. As far as I am aware, no one has gone back to those theories and assumptions with the new technology available to determine whether those assumptions are, in fact, valid.

I have no idea what this means. Perhaps Wagner could tell us what those "assumptions" are and what the connection is between Hutton and Smith and modern radiometric dating. Both Hutton and Smith were famous geologists, but they were both dead a century before radioactivity was discovered, so I'm rather baffled by the suggestion that radiometric dating is based upon any "theories" that they came up with. Perhaps here he is just referring to uniformitarianism, a concept that is commonly distorted by creationists, or to relative dating using index fossils (Hutton was a key figure on the first, Smith on the second), but those things have nothing to do with radiometric dating.

Until such time as the initial theories on which evolution is based are reviewed and tested and reexamined (as evolutionists demand be done with every scrap of data produced by "intelligent design theorists"), the assumptions should not be taught as fact.

But so far, these untested assumptions appear to be mostly mythical. Indeed, relative and absolute dating techniques act as wonderful checks on one another. Relative dating is the idea that older strata were obviously deposited first and therefore are at the bottom and the strata get newer as you go up in a given outcrop. This is true 99% of the time, and is only untrue when tectonic activity has disturbed the strata through fault thrusting and overthrusting, both of which are easily identifiable by the vast amounts of evidence left behind (enormous slabs of rock do not get thrust up through the surface of the earth without leaving lots of evidence behind). An excellent example is the Lewis overthrust at Glacier National Park. Absolute dating, through radiometric techniques, provides an excellent check on this technique because relative dating was postulated centuries before radioactivity was even discovered. So now we can take an entire column of undisturbed strata and use radiometric dating to date the specific strata all the way up (technically, we test the age of igneous intrusions within and between strata, not the strata themselves) and the results are a perfect match. If that were not the case, all of our "assumptions" about relative and absolute dating would proven wrong. The fact that they do coincide perfectly is powerful evidence that these "assumptions" are in fact accurate descriptions of nature.