It could be either side. Note, however, that the discussion, at least as conducted over at the linked comment threads, is quite asymmetrical: Incompatibilists say quite openly that they consider compatibilism to be merely a crutch manufactured to soften the blow of determinism, that compatibilists are deluded or even outright dishonest, and that everybody should stop using the term "free will" and, depending on their mood, sometimes also the term "choice", because they supposedly mean something supernatural. Compatibilists, on the other side, merely reply that these terms do not necessarily mean something supernatural, and would you please stop talking about us in this aggressive and demeaning way when the discussion is only about terminology anyway?
Or in other words: Incompatibilists condescend towards compatibilists but the compatibilists do not condescend back. That might explain something about the dynamics of this discussion.
To recap: When discussing free will vis a vis determinism, it is generally assumed that there are three different positions, or groups of people:
- Those who hold that we have a form of free will that allows us to make decisions independently from the laws of physics, our genetic makeup, the environmental influences that shaped us, our current state of brain chemistry, whatever, either because our body is steered by a supernatural soul (contra-causal/dualist free will) or without any attempt at explanation because it is a necessary premise for libertarian ideology (libertarian free will).
- Those who hold that everything is determined by cause-and-effect, with perhaps a bit of (quantum) randomness thrown in, and thus our decisions are also predetermined with a bit of random, and thus it does not make sense to speak of free will and choice because those terms are commonly understood in the sense that the first group is advocating* (incompatibilism).
- Those who hold that everything is determined by cause-and-effect, with perhaps a bit of (quantum) randomness thrown in, and thus our decisions are also predetermined with a bit of random, but it still makes sense to speak of free will and choice because those words do not necessarily imply anything contra-causal and supernatural*, and even given determinism we still need some terms to describe the difference between somebody acting out of their own free will and being forced to do something, or between a kleptomaniac and somebody stealing for profit (compatibilism).
So why would I think that the first two positions do not really exist? Aren't there a lot of people advancing them?
It is helpful here to differentiate between what people pretend to believe for strategic reasons or believe they believe because they have not thought things through on the one side, and what people actually do believe as demonstrated by their actions on the other. Two well known examples will suffice to make the point.
There are quite a few religiously or postmodernistically inclined people around who claim that we can never know anything, that every claim, even those supported by the best scientific evidence available, is mere opinion or ideology. Still, even these people will not attempt to walk through walls because they know from experience that it is impossible, and they will still eat food in the knowledge that it will nourish them. In other words, although they claim to believe that we cannot know anything, they still show through their actions that they really believe that we can know things.
(And really science is nothing but a more sophisticated variant of repeatedly trying to walk through walls to see if it works. If you accept the kind of knowledge that allows you to leave an apartment without getting bruises all over your forehead, all of science including evolution, vaccination, or climate modelling follows by logical extension.)
Similarly, it is often pointed out that most religious believers do not, no matter how much they believe that they believe it, really believe in a happy afterlife in heaven, as demonstrated by the facts that they fear death, avoid danger, and mourn over dead friends and relations. (In this case, as opposed to the first, it pays to insert a "most" into the sentence because there actually is a significant minority of martyrs, jihadists, and other assorted fundamentalists whose faith is strong enough to overcome fear of death and danger. Most religious people, however, can merely be said to hope for the afterlife.)
Now let us apply those considerations to the free will/determinism controversy. I have previously argued that no sane human actually believes in contra-causal or dualist free will in practice, although they may claim to do so for the purpose of religious apologetics or because they simply have not reconciled the contradiction between their claim and their actions.
There are two angles from which we can look at the issue to realize that this is true. First, if somebody really believed in contra-causal free will, they would have no way of anticipating other people's actions, and thus they would go mad. Second, try to figure out what contra-causal free will would look like, how it would differ from determinism or randomness. Take your time and try. It really cannot be done. There are precisely two options: either something follows some rules, regularity, or logic, which is determinism, or it is random. And the latter is not what a dualist would mean with free will either. So even if they call it supernatural (whatever that is), there would still be some deterministic rules - even if they are hidden, beyond-our-understanding, mysterious-are-the-ways-of-the-LORD-y deterministic rules - behind a behavior or it would be random behavior.
Whether you agree or not, so much I had already concluded to my own satisfaction. The recent round of discussion over at WEIT, and in particular some rhetorical questions by commenters Vaal and Coel and the non-answers provided by incompatibilists, have now convinced me that there are no incompatibilists either. Or let us say, nobody who is sound of mind is really, in practice, an incompatibilist.
Because if one would really believe that due to the predetermination of human actions there is "no difference" between doing something out of one's own free will and being coerced into doing something, or between falling out of a window and jumping out of a window, then one would have to treat the people who do either exactly the same. By not treating people equally for the same actions, regardless of their insanity or intentions, by not prosecuting a landslide for killing somebody, incompatibilists demonstrate as clearly as a postmodernist using a door that they do not actually hold the beliefs that they pretend to hold.
In summary, every sane human is a compatibilist determinist. There are those who have examined their beliefs and thus call themselves compatibilists. Then there are surely many (especially religious) people who wrongly believe they are not determinists because they have so far failed to reconcile their claims with their pragmatic behavior that only makes sense if they really believe that determinism is true. And finally there are some people who behave in every detail as compatibilists, and who have taken the compatibilist stance for dealing with responsibility and choice in a deterministic universe, but who have taken an irrational dislike to the word "free will".
That is it.
*) It is perhaps too much to hope that we could at some point examine empirical evidence on this fundamental premise of the incompatibilist stance. For me, those terms simply do not imply what they appear to imply to an incompatibilist. Maybe I am in the minority here and most other humans see them as supernatural concepts, but I would like to have some actual data, and it may well be that those data would surprise this or that incompatibilist. At a minimum, the following is already clear: The terms "free", "degree of freedom" and "choice" have numerous applications in the vernacular, in science and in mathematics that have no contra-causal or supernatural implications whatsoever, and in my native language, "freiwillig" does not have any such implications either because it is simply the German word for "voluntarily".