[msarchet]

> And yet I can speak concretely about a hydrogen atom

You can talk about some abstractions about how a hydrogen atom works, but we don't fully understand everything about atomic structure. We don't know if there is something that makes up the structures of subatomic particles becuase we don't have particle accelerators that have enough energy for us to peer deeper into what quarks are made up of. We don't even know if we've found all the types of particles.

[Robotbeat]

Actually, we do fully understand everything about the atomic structure of the hydrogen atom, everything relevant to chemistry and how life (for instance) works. If we have not yet unified the fundamental forces, that doesn't mean we don't have an INCREDIBLY detailed and complete understanding of the hydrogen atom.

Corner cases in several layers lower than chemistry vs not even really knowing where a memory is stored!

[Supermancho]

> Actually, we do fully understand everything about the atomic structure of the hydrogen atom,

Not sure where that hubris comes from. There are physical phenomena we have not been able to test, so there will always be unknowns and assumptions based on (abstract) modeling. eg the metallic liquid hydrogen described here https://edu.rsc.org/soundbite/hydrogen-falls-apart-under-pre...

[Robotbeat]

It comes from the unreasonable effectiveness of quantum electrodynamics. That we predicted a metallic state of hydrogen (a sort of molecular, not atomic, structure) under an extreme corner case (extreme pressure) over 80 years ago (well before it could be experimentally verified) just highlights what I mean.

And I don’t mean to say that neuroscientists are doing shoddy work. Far from it! The brain is a far more complex entity than RNA or a hydrogen atom. The task is MUCH harder! But I am showing that high level of specific, concrete knowledge IS possible in the physical sciences. Memory in the Brain is a physical process as well, but we have only a relatively vague understanding of the specifics of it. We can sequence DNA or RNA accurately with relative ease. We cannot do the same with memories in the brain.

[Supermancho]

> That we predicted a metallic state of hydrogen

You're missing the point. The idea that the predictions are the same as knowledge illustrates the misunderstanding. We do not know because we cannot prove it. I shouldn't need to get into the reason we produce experimental evidence eg https://www.forbes.com/sites/startswithabang/2019/07/06/ask-... - via the LIGO and Virgo detectors

[d110af5ccf]

@Robotbeat isn't the one missing the point here. The incredible accuracy of those predictions serves as a testament to just how well we do understand that particular phenomenon. Now compare to neuroscience, where we struggle to accurately make (by comparison) the most basic of predictions.

[Supermancho]

> Now compare to neuroscience, where we struggle to accurately make (by comparison) the most basic of predictions.

I'm not addressing the hand wavy nature of the article, which is self-evident. This is irrelevant to the point being discussed.

[monocasa]

Quantum chemistry is a field with a lot of unknowns still. To say that chemistry has a complete understanding of the hydrogen atom is inaccurate.

[d110af5ccf]

... what?! We can accurately predict hydrogen (and helium!) energy characteristics to _absurd_ accuracy levels. The issue is that even a system as simple as a single helium atom is prohibitively computationally expensive.

[monocasa]

There's more to quantum chemistry (and hydrogen atoms) than what you're saying. If you define chemistry tautologically as what we know, then sure I guess.

[d110af5ccf]

To be clear, I'm not disputing unknowns in quantum chemistry in general (I lack the requisite background). But I was definitely of the understanding that single atom (and possibly somewhat larger) systems are thoroughly understood from a mathematical perspective at this point. I would appreciate concrete examples of open questions, either for hydrogen atoms specifically or for quantum chemistry more generally.