Essay stands on it’s own but for more context:
See part 1 on theories of truth
See part 2 on solipsism
See part 3 on scientific (anti)realism.
This conclude the essay series on Truth and Existence: A Philosophical Landscape
How Natural is a Naturalist?
If we have all these messes now, what shall we do with the actual unobservable (with a capital U) features of the world? What are we going to do with metaphysics?
In this case, some folks have specific stringent rules, sometimes they call themselves empiricists, but I think a naturalist is a correct label. Empiricism is the theory that all knowledge comes from sense-experience, and right off the bat, you see that empiricism accommodates perfectly metaphysical features of the world: arts, morality, religion, and all of those things. However, a naturalist will deny the existence of (some of) those elements, especially a supreme being, think high-octane atheism.
And who exactly is a naturalist?
A naturalist professes to believe that all that there is, is the material world, and the only way to know the truth about all that there is (i.e., the material world) is through science.
Let’s take on the first claim: “all that there is, is the material world.” This simply implies that the only thing which exists is what we know to be true empirically (empirically circumscribed in the word ‘material’). By this provision, a naturalist is also a materialist; for example, she will think that a person is more or less a material object, nothing more. However, we also have a naturalist, non-materialist position, which I will get to in a second.
Claim two: “the only way to know the truth about all that there is (i.e., the material world) is through science.” Here, a naturalist will go further and say, all that can be said to exist is only discoverable through science, even if we don’t know it to be true now.
A naturalist who is a non-materialist will be fine with the following statement: there are other things that are not material (breaking away from the traditional position), only that science needs to somehow re-work its framework to admit those things. However, this position is quite elusive, so we will leave this for now and restrict ourselves to the traditional naturalist position that I have stated: the naturalist—materialist that subscribes to claims one and two.
And I am afraid to say, even a cursory look at those claims promise heavy disappointments.
Suppose a belief system exerts that all that can be said to exist is only discoverable through science. In that case, perhaps, the naturalists must show us how science shows that ‘all that can be said to exist is only discoverable through science’ (since all things include the belief of naturalism itself.)
In order words, 1) if all things are discoverable only via science, then 2) it has to follow that it is discoverable via science that all things are discoverable only via science. However, since it is not discoverable via science that all things are discoverable only via science, then scientific naturalism has to be false. Such that the best scenario is that our naturalist friends better quickly declare their faith – as we are dealing with a faith-based position usually disguised as something else.
And the reader must not miss the apparent self-defeating motif.
What am I saying here? I am saying that if this were to be a soccer game, a naturalist would have scored at least an own goal. In other words, if naturalism is ever taken to be true, then it must be false, a shot in the head, that kind of thing.
And the problem is that for the scientific realist, we just slid into the metaphysical realm, far, far beyond the reach of science. To be explicit, science here refers to the scientific method, the hypothetico-deductive (H-D) model.
But we mustn’t let go that fast. Claim two: “the only way to know the truth about all that there is (i.e., the material world) is through science.” This is the same as saying: Thou shalt not trust anything that is not a product of science (again, for emphasis’ sake, we are speaking to the H-D model). Then the question is, what the heck are we going to do with mathematics and logical truths?
Plantinga, Naturalism, and Everything In-Between
That aside, the cerebral Christian philosopher Alvin Plantinga discovered yet another conflict.
You see, naturalism sits right on top of biological evolution. If naturalism is the roof, evolution is the actual building. The kind of evolution we are speaking to here is a purely naturalistic evolution – driven by natural selection, the idea that nature selects for the bests, ‘the survival of the fittest.’
This leads us to the evolutionary argument against naturalism (EAAN), which holds that a simultaneous belief in evolution and naturalism is unreasonable. It goes something like this: 1) Imagine a being in another galaxy – a being analogous to humans. Imagine that for them, naturalism and evolution are both true. Given that their behaviors are the consequence of their brain function (neural states) and given that these neural states are a product of a blind, random evolutionary process that selects for adaptable traits. Therefore, their cognitive outputs should be deemed unreliable from a truth perspective, including the belief that naturalism is true. 2) If this conclusion holds for this being in that galaxy, then it must hold for humans. Two adjoining conclusions flow from this reasoning. 3a) There is a defeater for a simultaneous belief in evolution and naturalism. 3b) There is a defeater for any belief that the brain births, including evolution and naturalism.
Let’s add more meat to this argument, but before that, a little bit of summary (and rigor). Let N = naturalism, E= the belief in the contemporary evolutionary process, and R = the reliability of reasoning faculty. EAAN states that p(R|N&E) is very low; that is, the probability of the reliability of the cognitive faculty is very low given that naturalism and naturalistic evolution are both true.
Now the meat, or if you will, the crux of the argument: the critical part of the evolution-cum-natural selection theory is that it selects for adaptable features, in as much as the behavior is adaptable, the organism will survive, and an adaptable behavior doesn’t have to be true – there is nothing that requires truth in adaptability. But how do we deal with the relationship between belief and behavior? Let’s map out three pathways very quickly.
First, let’s take epiphenomenalism, which dictates, in this context, that belief does not cause behavior, but the inverse is true. Just like the sound of a car doesn’t have any causal effect on the car engine. If we grant this philosophical framework – belief as an exhaust fume of behavior – p(R|N&E) will be low. Two important points are required to reach that conclusion. 1) Beliefs will be ‘invisible’ to evolution, and no probability of ‘true beliefs’ will be conferred. 2) If the probability of the ‘trueness’ of a belief is 0.5 (given 1, say we flip a coin), then the probability of the ‘trueness’ of a bunch of beliefs will therefore be terribly low (the multiplicative rule of probability).
Another possibility is to grant that beliefs are neural networks/structures that cause behaviors, not by the belief content (say a belief that p is true where p is the belief that ‘the Coca-Cola company headquarters is in Atlanta’), but by virtue of neurophysiological properties. This will be a case of semantic epiphenomenalism where p(R|N&E) will still be low since it is the content of a belief that determines trueness and not neurophysiological properties that are subject to the forces of natural selection.
And yet another possibility exists: let’s say that belief effectively can cause behavior, we can still argue that p(R|N&E) will be low. This is because belief alone cannot cause behavior; we can have a combination of say, desire, and belief, causing the behavior. Now, it is not impossible for a desire to lead to a false belief, and, again, on the grounds of natural selection, there is no reason to reject a false belief that is adaptable. No reason whatsoever. In short, we can have desire-belief pair that leads to a right action where the belief is false, and so on and so forth. (For interested folks, you can pick up Plantinga’s paper on EAAN for a head-spinning read.)
But for now, these arguments will have to do – one against scientific naturalism, the other against philosophical naturalism. The writer rejects naturalism – it is most certainly false.