Reading Time: 4 minutes

CS Lewis fashioned the Argument from Reason and it has since been taken on by Christian philosophers and apologists such as Alvin Plantinga (in the form of the Evolutionary Argument Against Naturalism – EAAN) and Victor Reppert. For a bit of background reading, it is well worth grabbing John Beversluis’s excellent C.S. Lewis and the Search for Rational Religion (UK). I will be writing a series of posts on this and the first will concern doxastic voluntarism, which I will later explain (and about which I have written about before and podcast segmented here).

The argument broadly goes like this, as Lewis quotes of JBS Haldane in Miracles:

If my mental processes are determined wholly by the motions of atoms in my brain, I have no reason to suppose that my beliefs are true… and hence I have no reason for supposing my brain to be composed of atoms.

The idea is that naturalism as a worldview is either self-refuting or indefensible. It can be formalised as follows:

1. No belief is rationally inferred if it can be fully explained in terms of nonrational causes.

2. If naturalism is true, then all beliefs can be fully explained in terms of nonrational causes.

3. Therefore, if naturalism is true, then no belief is rationally inferred (from 1 and 2).

4. We have good reason to accept naturalism only if it can be rationally inferred from good evidence.

5. Therefore, there is not, and cannot be, good reason to accept naturalism.

Or, simply put, determinism renders naturalism rationally indefensible.

Much ink has been spilt on this, and oral exasperation, not least in the famous arguments between fellow Christian Elizabeth Anscombe and Lewis himself.

Without getting into the finer details of the syllogism above, let’s look at the basic idea that determinism supposedly renders a conclusion absent of rational choice, per se. This is actually something called doxastic involuntarism. Doxastic (pertaining to belief) voluntarism is a position whereby one believes that they have voluntary control over what they believe.

Take the claim “the moon is made of cheese”. I cannot simply make myself believe this claim. There is a threshold for this claim where if the evidence was to pass it, I would believe this claim. That threshold will differ from person to person but I cannot consciously control that threshold. I will simply believe, based on a bunch of causal variables, what I believe when certain thresholds are passed.

I can’t will myself to believe in God, for example, just sitting there, straining at my brain. You can’t choose what convinces you.

If I believe that the 9/11 conspiracy theory is false at point t1, and then we moved onto t7, and then we rewound back to t1 where every variable, wave function and atom was identical, what would underwrite me “choosing” to believe that the 9/11 conspiracy theory was true? I wouldn’t just will that change, there would need to be a change in the causal variables to enable a change in belief.

So the idea of doxastic voluntarism (DV) is very closely related to libertarian free will indeed. The notion that I could have a background desire to either believe or not believe in a given position is itself victim to these causal variables. There is a grounding of evidentialism here.

Some people adhere to indirect doxastic voluntarism. This is the position we can influence certain variables that influence a belief: a desire or decision to read a certain book or to go to church or listen to a pastor that could then lead us to a belief in God. But these decisions themselves are still victim to causal variables and chains and so you cannot extricate yourself from the libertarian free will situation.

If DV was true, we would have compelling evidence of people changing their minds willy-nilly, but we don’t.

You could argue that certain positions that are lacking in any meaning, consequence or evidence at all could be resultant from DV, such that the belief that it is raining on Jupiter right now. But such a belief wouldn’t really be a belief, it would be a random lumping for a position. You wouldn’t really believe it. You wouldn’t stake your mortgage on it. It is not evidentially based.

Okay, so that’s laid out DV. Essentially, you can’t choose what you believe.

How it is relevant here is that if Christians say that you can’t “choose to believe” naturalism because your thought processes are determined and not rationally arrived at (more on this claim in the next post), then the same claim can be thrown right back at Christians for all of their beliefs. There is the notion that the Holy Spirit washes over you, or that something just clicks, or a light is turned on in your mind when reading a certain biblical passage, these are all examples of the same kind of thresholds being reached through nonrational (deterministic) processes. Indeed, any beliefs would need to navigate the landscape of doxastic voluntarism and involuntarism. What is good for the goose is good for the gander.

After all the laying out of this, it is this last paragraph that is essentially my argument here. If the Christian wants to really use the Argument from Reason, first of all, they need to somehow prove the coherence of doxastic voluntarism, and that’s a very tall order because it goes hand in hand with proving (the coherence of) libertarian free will.

And no one’s done that.

Stay in touch! Like A Tippling Philosopher on Facebook:

A Tippling Philosopher

You can also buy me a cuppa. Or buy some of my awesome ATP merchandise! Please… It justifies me continuing to do this!

Avatar photo

Jonathan MS Pearce

A TIPPLING PHILOSOPHER Jonathan MS Pearce is a philosopher, author, columnist, and public speaker with an interest in writing about almost anything, from skepticism to science, politics, and morality,...