What Evolutionists Don’t Understand About Methodological Naturalism

[Ed: An oldie-but-goodie from July 5, 2011]

OK let’s try this again. One more time, this time with pictures. In their celebrated volume  Blueprints, evolutionists Maitland Edey and Donald Johanson argued that “What God did is a matter for faith and not for scientific inquiry. The two fields are separate. If our scientific inquiry should lead eventually to God … that will be the time to stop science.” Similarly for evolutionist Niles Eldredge, the key responsibility of science—to predict—becomes impossible when a capricious Creator is entertained:

But the Creator obviously could have fashioned each species in any way imaginable. There is no basis for us to make predictions about what we should find when we study animals and plants if we accept the basic creationist position. … the creator could have fashioned each organ system or physiological process (such as digestion) in whatever fashion the Creator pleased. [The Monkey Business, p. 39, Washington Square Press, 1982.]

Or again, evolutionist Paul Moody explains that:

Most modern biologists do not find this explanation [that God created the species] satisfying. For one thing, it is really not an explanation at all; it amounts to saying, “Things are this way because they are this way.” Furthermore, it removes the subject from scientific inquiry. One can do no more than speculate as to why the Creator chose to follow one pattern in creating diverse animals rather than to use differing patterns. [Introduction to Evolution, p. 26, Harper and Row, 1970.]

Likewise Tim Berra warns that we must not be led astray by the apparent design in biological systems, for it “is not the sudden brainstorm of a creator, but an expression of the operation of impersonal natural laws, of water seeking its level. An appeal to a supernatural explanation is unscientific and unnecessary—and certain to stifle intellectual curiosity and leave important questions unasked and unanswered.” In fact, “Creationism has no explanatory powers, no application for future investigation, no way to advance knowledge, no way to lead to new discoveries. As far as science is concerned, creationism is a sterile concept.” [Evolution and the Myth of Creationism, pp. 66, 142, Stanford University Press, 1990.]

In his undergraduate evolution text Mark Ridley informs the student that “Supernatural explanations for natural phenomena are scientifically useless,” [Evolution, p. 323, Blackwell, 1993] and commenting on the Dover legal decision Eugenie Scott of the National Center for Science Education explains that supernatural explanations:

would be truly a science stopper, because once we allow ourselves to say, “Gee, this problem is so hard; I can’t figure out how it works—God did it,” then we stop looking for a natural explanation; and if there is a natural explanation, we’re not going to find it if we stop looking.

Over and over evolutionists today agree that science must strictly be limited to naturalistic explanations. One finds this throughout the evolutionary literature and it is a consistent refrain in discussions and debates about evolution.

But this sentiment by no means arose with today’s evolutionists. In 1891 UC Berkeley professor Joseph LeConte argued strenuously for this philosophical mandate:

The origins of new phenomena are often obscure, even inexplicable, but we never think to doubt that they have a natural cause; for so to doubt is to doubt the validity of reason, and the rational constitution of Nature. So also, the origins of new organic forms may be obscure or even inexplicable, but we ought not on that account to doubt that they had a natural cause, and came by a natural process; for so to doubt is also to doubt the validity of reason, and the rational constitution of organic Nature.

Likewise Darwin argued that whether one “believes in the views given by Lamarck, by Geoffroy St. Hilaire, by the author of the ‘Vestiges,’ by Mr. Wallace or by myself, signifies extremely little in comparison with the admission that species have descended from other species, and have not been created immutable: for he who admits this as a great truth has a wide field open to him for further inquiry.”

Explanations needed to be naturalistic for scientific inquiry. And as usual the foundations for this evolutionary mandate long predate 1859. Miracles were increasingly eschewed by leading thinkers and a century before philosopher David Hume had made persuasive arguments against miracles. Much of Hume’s material came from theological debates earlier in the century. On the continent leading Lutherans had already discarded the supernatural.

Method, completeness and realism in pictures

So when an evolutionist today insists that science must be naturalistic he is standing on a deep foundation of ideas. But setting aside this history for a moment, what about this argument? Remember that these same evolutionists claim their idea is also a fact. Is there not something curious about these tandem claims? I was once in a debate where the evolutionists claimed that we know evolution is a fact, and that it also is necessary in order to do science. How did they know that? Let’s have a look.

First, imagine the set of all possible explanations, as represented by the blue area below:

Because the blue area contains all possible explanations, it includes false as well as true explanations, lousy as well as good explanations, aesthetic and clumsy ones, and natural and non natural ones. It is every possible explanation in one set.

Now consider the set of all solutions that are according to a particular method, such as naturalism, as illustrated in the orange area below. All explanations that are strictly naturalistic are in the yellow area, and all other explanations are outside the orange area. Because the blue area contains all possible explanations, the orange area is a subset—it is wholly within the blue area.

Next consider the set of all true explanations as represented by the green circle below. These true explanations provide realistic models of nature. Again, this set of explanations must be wholly within the blue area, but otherwise we don’t know just where this green circle is. It could be in the orange area, it could be outside the orange area, or it could overlap. We don’t know what the true solutions all are, which is why we do science.

I have drawn the green circle above as partly inside and partly outside the orange area merely to illustrate the possibilities. But we don’t know where it is, and therefore whenever we mandate, a priori, a method such as naturalism, we automatically exclude a set of explanations that might be true.

In the early days of modern science philosophers were keen to this issue. Francis Bacon, for instance, wanted science only to pursue true explanations. But Bacon also wanted science to restrict itself to naturalistic explanations. Bacon realized that the restriction to naturalism would exclude any realistic, true, explanations that were not strictly naturalistic.

Bacon said that such non naturalistic phenomena should not be pursued by science. So Bacon insisted on naturalism and realism, but forfeited completeness. Science would not investigate all things. The thick black line below illustrates how this position limits itself to explanations that are both realistic and naturalistic, while potentially forfeiting some true explanations (depending on where exactly the green circle really is).

Like Bacon, another early philosopher, Rene Descartes, also insisted on naturalism. But he didn’t like the idea of forfeiting completeness. Descartes wanted science to be able to investigate all phenomena. But what if some realistic, true, explanations fall outside of naturalism? So what.

Descartes solution was to forfeit realism. Science, according to Descartes, would occasionally produce untrue explanations that otherwise could very well be useful. This approach is illustrated by the thick line below that encompasses all the naturalistic explanations, but misses some of the true explanations. Science might produce useful fictions along the way. Descartes mandated method and completeness, but in doing so had to forfeit realism.

After Descartes several scientists did not like this idea of forfeiting realism, as Descartes did, or forfeiting completeness, as Bacon did. These empiricists were interested in true solutions for all phenomena. This approach is illustrated below with the thick line encompassing the true solutions. But in order to maintain such realism and completeness, this approach cannot guarantee what method would be necessary. They might require non naturalistic explanations, for instance. So this approach provides realism and completeness, but forfeits any guarantee of method, such as naturalism.

Bacon, Descartes and the empiricists represent three different approaches to doing science. All are logically consistent. And who knows, the different methods might yield different insights—let a thousand flowers bloom.

But of course all three approaches have a limitation. Like the Heisenberg Uncertainty Principle, you cannot have realism, completeness and method all in one. You cannot have your cake and eat it too.

This brings us back to the evolutionists. Unlike Bacon, Descartes and the empiricists, evolutionists do have their cake and eat it too. They claim evolution is a fact, they mandate naturalism, and their science knows no limits. They have realism, method, and completeness all together. How can this be?

The answer is simple. One cannot have realism, method, and completeness simultaneously without some extra, non scientific, knowledge. Evolution’s gnosis is, of course, that true solutions are, indeed, naturalistic. This is illustrated below by the thick line that encompasses all true explanations, but it is also wholly naturalistic. How so? The trick is that the green circle has been moved. It is completely within the orange area. Knowing the location of the green circle, even before doing the science, is evolution’s gnosis—their secret knowledge.

It is this secret knowledge the evolutionists possess that allows them to have their cake and eat it too, and this brings us back to the history of the idea. There is no great mystery here, for evolutionists have for centuries made strong theological arguments that the world must have arisen naturalistically. The true explanations are all naturalistic. Therefore it is little wonder that, while not knowing how the world could have evolved, evolutionists are sure it did evolve. Evolution, one way or another, is a fact.

It is here that many fail to appreciate evolution’s conundrum. They often criticize evolution’s method mandate. Have not evolutionists been wrong to insist on methodological naturalism? No, such a method is perfectly fine.

The problem with evolution is not its insistence on method, but on its underlying theology. By insisting on method and realism and completeness, evolutionists are literally not equipped to consider other legitimate possibilities. They have already made a metaphysical commitment, without knowing whether or not it is true. They have confined themselves to a box. For when problems are encountered there is no way to tell whether the correct naturalistic solution has simply not yet been found, or whether the phenomenon itself is non natural. Of course evolutionists must always opt for the former, no matter how absurd the science becomes.

So the problem with evolution is not that the naturalistic approach might occasionally be inadequate. The problem is that evolutionists would never know any better. The evolutionists truth claims, and the underlying theology, have immense consequences. Religion drives science, and it matters.