The evolutionary argument against naturalism
Alvin Plantinga (1932), professor emeritus of philosophy at the University of Notre Dame, is a leading theistic philosopher and opponent of evolution. He has proposed an intriguing, and specious—yet non-the-less intriguing—argument against evolution. It is intriguing for several reasons: First, because on the face of it, it is plausible. Second because it is typical of a whole class of specious arguments. Finally, because it highlights the difference between how scientists and philosophers approach a problem.
The argument runs as follows: The naturalist can be reasonably sure that the neurophysiology underlying belief formation is adaptive, but nothing follows about the truth of the beliefs depending on that neurophysiology. In fact, he’d have to hold that it is unlikely, given unguided evolution, that our cognitive faculties are reliable. It’s as likely, given unguided evolution, that we live in a sort of dream world as that we actually know something about ourselves and our world (original emphasis). In other words, if people in fact evolved, they could not trust their cognitive faculties to give them the truth and hence, do science. He goes on to argue that it is only possible to trust our cognitive faculties if people are created in God’s image.
It is amusing that unbelievers argue the opposite; namely that the existence of a God means science is impossible since he/she/it could override the rules of nature at will and there would be no reason to assume constant laws. Both are correct to this extent: Absolute knowledge is impossible, independent of God’s existence. But back to Plantinga’s argument; it hinges on the concept of truth, or equivalently, reliability. But what is truth? A profound question—or a meaningless one. The difference between profound and meaningless is often vanishingly small.
At one level, the idea of truth is simple: Does the testimony of the person on the witness stand agree with what happened? Or perhaps the simpler question: Does the testimony agree with what the person thinks happened? The second is a less stringent requirement. But from this simple concept, the grand metaphysics concept of TRUTH ™ is generated. Whatever this grand metaphysical concept is, science is not concerned with it. Is it TRUTH ™ that colds are caused by viruses? The reductionist, at least if he believes in string theory, would say no. Colds, like all other phenomena, are caused by how strings vibrate in eleven dimensions. Viruses are just a wimpy low-energy approximation to the real TRUTH ™.
In science, we build models for how the universe works, which usually have a limited range of validity. Think of classical mechanics which is only valid for velocities much less than the speed of light. Is classical mechanics the TRUTH ™? No, certainly no, it fails in various places. But it is certainly useful. Science is a natural extension of the model building the unconscious mind does all the time, which is necessary for us to survive in a hostile world. The surprising thing is not that beings who evolved created science, but rather, that they did not do it sooner. Plantinga’s problem is that he does not understand what science is or how it works—seeking effective models rather than the TRUTH ™, whatever that may be. He should have known better, since by the Duhem-Quine thesis, no model can be falsified. Arguing that the current models have deficiencies is never enough. You have to provide better ones with more predicative power.
In the same manner that Plantinga’s argument relies on the grand metaphysics concept of TRUTH ™, many arguments in philosophy rely on similar word definitions. A prime example is the ontological agreement for God’s existence. First proposed by Anselm of Canterbury (1033 – 1109), the argument goes as follows: Define God as the greatest possible being we can conceive. If the greatest possible being exists in the mind, it must also exist in reality. If it only exists in the mind, a greater being is possible—one which exists in the mind and in reality. Note that his argument hinges on the definition of greatest. My daughter believes that anything, no matter how great, can be made greater by being pink. Thus the greatest being is pink. If I define non-existence as being greater than existence, the ontological argument becomes an argument for God’s nonexistence. Evil is another word that is frequently made into a grand metaphysical concept, EVIL™, and used to justify various philosophical positions. The concept of actions I do not like is then taken a step further and personified in the concept of the devil.
While our concepts and word definitions may reflect reality, they do not constrain it. In the end, models founded on observation take precedence over philosophical arguments based on word definitions and phenomenologically unconstrained speculations. If such philosophical arguments disagree with scientific models, so much the worse for them. Thor showing up for Thursday afternoon tea at the Empress Hotel would make all arguments regarding his existence moot. One observation is worth a thousand philosophical arguments.
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 See Ecclesiastes chapter 4 for why this definition may be reasonable.
 You can tell it is Thor because he would be carrying a large hammer and one of the goats pulling his chariot would be limping.