Built on Facts

There’s a very interesting column in the New York Times that’s caused a lot of discussion in various corners of the internet. That tends to happen often these days when science and theology intersect. The column is The Neural Buddhists, and its thesis is that since our minds are a result of our brains, there’s really nothing of substance to the idea of a soul.

To these self-confident researchers, the idea that the spirit might exist apart from the body is just ridiculous. Instead, everything arises from atoms. Genes shape temperament. Brain chemicals shape behavior. Assemblies of neurons create consciousness. Free will is an illusion. Human beings are “hard-wired” to do this or that. Religion is an accident.

There’s a lot to unpack here. Some of these statements are obviously and uncontroversially true. Some of them (”neurons create consciousness”) are much less so. I’d love to spend about ten pages discussing every sentence in detail, but hey, this is a blog and there’s time enough for all that later. The real physics content is in the second-to-last sentence. What does “hard-wired” mean? Well, literally it’s a metaphor from computing. A hard-wired circuit does exactly one thing, and it can’t be modified short of disassembling the circuit. This is as opposed to the computer you read this on, which can be modified by adding different software.

In a more fundamental sense though, science has mostly assumed that everything in the universe is hard-wired in the sense that there’s only one possibility for “what happens next”, and that possibility can be uniquely determined by looking at the relevant physical equations. Drop a stone, and one second later it will be 4.9 meters lower than it started. The stone doesn’t have any “free will”; it can’t decide simply not to fall. This is not a new idea. Determinism - the idea that everything that happens follows with certainty from the laws of physics - has formally existed since Newton and less formally since at least the ancient Greeks. In modern physics we know determinism is not quite true, at least not in its original sense. Quantum mechanics includes processes which are fundamentally probabilistic. Even with perfect information about a system and perfect knowledge of the laws of nature, we’re still only able to make judgments about the odds of the various possibilties. In the macroscopic world the odds are overwhelming that the thing that happens will be just what classical physics predicts, but fundamentally there’s still that uncertainty. Even without quantum mechanics, the slightest imperfection in our information about the initial state of a system can often ruin our ability to extrapolate that state as far as we’d like into the future. The butterfly effect is the canonical example of that, and even in a purely classical world we couldn’t get around that limitation.

Is the scale of the systems in the brain small enough for quantum effects to make a difference? Is the brain a mathematically chaotic system? I don’t know. I don’t think anyone knows with certainty just yet, as various physicists (Penrose especially springs to mind) are right now at each other’s throats over just what effect if any quantum mechanics has on the brain. The jury is out, and speculation in the absence of data is just speculation.

Realistically, I think all this is overblown. Of course the universe is more-or-less deterministic. Of course our brains follow the laws of physics as they process our thought. But does this have any bearing on theology or atheism at all? Not that I can see. The question of free will in a physically governed brain would have been more dire in the perfectly deterministic universe of Isaac Newton than in the more modern universe of Max Plank and Edward Lorenz. And even the most pessimistic “no free will, no soul” interpretation would fit the worldview of John Calvin just as much as it would Richard Dawkins.

In short, let me leave you with a rule of thumb. Be skeptical of anyone who tries to draw philosophical conclusions about physics unless they have data to back it up. It’s not possible to build on facts without actually having facts to work with.