Yes, quite true, but in this thread, a bunch of people who know nothing at all about neuroscience and cognitive science - worse, who don't believe anyone anywhere knows anything about those subjects - are going to pontificate on why having a bunch of trained experts study the brain was always a terrible idea.

The thing I was always wondering about brain simulations is how to determine what level of detail is enough. What if neurons evolved to take advantage of some funny quantum phenomena that we may not even know about yet, and without this the simulation won't work? For this reason I would think that getting a simple brain simulation to work would at least help enumerate the physics most involved in their function.

Now maybe there is some extra physics that comes into play at scale (like some quantum-computery effect with human-size brains that induces conciousness) but maybe this would be detectable as small discrepancies in the small simulations (especially as they progress in size to e.g. mice).

Since brain has to work in a noisy environment, it is unlikely its function depends too much on details. Neurons can't depend on effects we don't know about, because if effect is large, we would know about it, and if effect is small, brain has to work with noise that size, so it is not necessary for us to get it right for its function. (It's a different matter for its exact output, but that's for later.)

You don't need to appeal to "quantum effect" to think that being able to understand, well enough to simulate, THE SIMPLEST NEURAL SYSTEM of any organism would be helpful before jumping in feet first with 1 billion euros into the most complex neural system. Of course it is a process over 10 years and they have "only" spent 200 million so far. I would expect that quite a bit of that money is going to study model organisms from c. elegans to mouse to chimpanzee. Studying simpler model organisms is one of the best ways we have to understand fundamental biological principles.

If there would be such a quantum effect it would contradict a lot of conventional theoretical physics, brains operate at high temperatures ~310 Kelvin, and the length scales involved are fairly large for quantum mechanics. You would only expect to see quantum effects at such large length scales at very low temperatures, because otherwise the correlation length is just too small.

My line of thinking is, say it'll cost X to model C. elegans.

For even the simplest mammals (let alone humans), surely the cost is >> X. So might it be a decent idea to give it a shot with C. elegans first? Because if we fail with C. elegans, we're almost guaranteed to fail with a mammal. And it's not immediately clear to me that we currently have the ability to do it successfully even for C. elegans.

I am definitely not a neuroscientist so maybe I am misguided. I'm also not wedded to C. elegans as being the ideal prototype, and I doubt anyone is (except possibly the people already studying C. elegans). But the first attempt should definitely be on something as simple as possible.