One wing of modernism is political liberalism. Liberalism is based on the idea of the self-creating, autonomous individual who is free to choose in any direction.
The other wing is a scientific materialism. The materialists believe that everything is a product of material causes, so that every action we take is ultimately predetermined (and could, in theory, be predicted).
You would think that the liberals and the materialists would wage intellectual war on each other. The two seem difficult to reconcile: a strict materialism is deterministic and so denies the very possibility of free will or the reality of individual choice.
Some moderns are aware of this problem. There was a debate at the Catallaxy website some time ago in which Jason Soon admitted that he and other moderns were haunted by the difficulty of reconciling what he refers to as philosophical naturalism with their political beliefs:
Naturalism holds that everything we are and do is connected to the rest of the world and derived from conditions that precede us and surround us. Each of us is an unfolding natural process, and every aspect of that process is caused, and is a cause of itself. So we are fully caused creatures.
Of course this is just another way of saying naturalism implies determinism at some fundamental level even if we know that in practice we cannot (at least for now) have the ability to pull certain strings to make humans function like clockwork. I do consider myself a naturalist but a question that haunts (in my view unjustly) those of us who are simultaneously philosophical naturalists and politically libertarians is whether the two are reconcilable.
There follows a debate in which one of the contributors, Daniel Barnes, actually does step back from a full acceptance of the materialistic view. He writes that he doesn't want to dodge:
another basic difficulty, which is how you can say ‘choice’ is both vitally important (ie: be a libertarian) and an illusion at the same time. Call me old-fashioned - I probably am - but despite the compelling nature of deterministic arguments, and the semi-occult feeling of denying them, I still can’t...quite...go...there.
A commenter calling himself c8to then tries to reconcile free will with determinism as follows:
what we always meant by free will was the ability to look at a list of possibilities, run some algorithm and deterministically decide the goal maximising actions
Daniel Barnes shot back with this:
“Deterministically decide” is an oxymoron. Because if determinism is true, you ‘decide’ nothing. A scientist with sufficient data should be able to exactly predict what your “algorithm” will do - and, like every other event, it will have been exactly predictable since the dawn of time. If you call that a decision you might as well say a planet ‘decides’ to circle the sun.
If, though, it is difficult to reconcile political liberalism with a deterministic materialism, why have they successfully coexisted? One possible answer is to be found in a recent study on liberal and conservative patterns of belief. This study found that conservatives placed a far greater weight on "purity" than did liberals. A libertarian called Razib did the questionnaire on which the study was based and reported the results as follows:
when it comes to "Purity" I go farther than even the typical liberal. Here this might be my hard-core reductionist materialism coming through, I don't really believe that anything has an essence, everything is simply a collection of atoms, so talk of an act or object being pure or impure seems totally incoherent to me most of the time.
You can see in this quote how a "hard-core reductionist materialism" might work well together with political liberalism. The materialism undercuts the idea of essences, which then means that there is no given quality toward which things ideally develop. This removes a basic obstacle to individuals developing, as liberals wish them to do, in any direction.
So liberalism and materialism are in alliance when it comes to attacking a traditionally "essentialist" view of things and perhaps this helped them to combine to form the modernist mindset.
It's hardly an ideal combination though. Materialism might help liberals to strike down essentialism, but it does so at the expense of choice and free will. The liberal individual might be able to choose in any direction, but his choice is illusory as it is predetermined. He becomes a fully caused, rather than a self-created, creature.