Here is a prompt I gave to chatGPT:
- Is it so that chemists have been given the task by physicists to make sense of quantum physics in chemistry, a very difficult if not impossible task?
Short answer: yes—historically, chemists were effectively handed that task, and it may well be impossible in the strong sense that was implicitly expected. Let me explain carefully, without rhetoric.
1. How the Task Was Framed (Mostly by Physicists)
A canonical statement is due to Paul Dirac, who famously wrote (1929) that the fundamental laws needed for chemistry were already known, and that the difficulty was “only” their application.
This framed the division of labor as follows:
Physicists: discover the fundamental laws (quantum mechanics).
Chemists: apply them to atoms, molecules, reactions, bonding.
Implicit assumption:
Chemical concepts already exist in quantum mechanics and only need to be extracted.
That assumption is now known to be false.
2. What Chemists Actually Found
When chemists tried to “apply” quantum mechanics, they discovered something unexpected:
Quantum mechanics gives wavefunctions and energies.
Chemistry needs molecules, bonds, structures, reactions.
These do not appear in the fundamental formalism.
As shown rigorously by Hans Primas and by Robert Woolley, exact quantum mechanics contains:
no molecular structure,
no localized bonds,
no chemically distinguishable molecules.
So the task chemists were given was not “apply the theory,” but rather:
Invent a chemical ontology that quantum mechanics itself does not provide.
3. Why This Task May Be Impossible (in Principle)
The impossibility is not practical but conceptual.
To succeed fully, chemists would need to:
derive bond, structure, and molecule uniquely and invariantly
from the exact quantum formalism
without arbitrary approximations.
But:
there is no bond operator,
no structure observable,
no unique partition of electrons or space,
no preferred basis.
All chemically meaningful entities arise only after:
Born–Oppenheimer separation,
symmetry breaking,
orbital localization,
model-dependent idealizations.
This is why Robin Hendry argues that chemical structure is not derivable but emergent.
So if the original task was:
“Recover chemistry from quantum mechanics”
then yes—it is likely impossible, not just difficult.
4. Why Chemists Still “Succeeded”
Chemists did succeed—but by changing the task.
Instead of deriving chemistry from physics, they:
built powerful model frameworks (VB, MO, DFT),
accepted approximation as constitutive,
treated bonds and structures as pragmatic theoretical entities.
This made quantum chemistry:
extraordinarily predictive,
technologically indispensable,
but not conceptually foundational.
In effect, chemists became mediators, not applicators:
they made quantum mechanics usable by adding chemistry to it, not extracting chemistry from it.
5. Was This a Category Error from the Start?
Arguably, yes.
Physics aims to describe:
universal, invariant, minimal ontology.
Chemistry aims to describe:
stable, manipulable, explanatory entities at an intermediate scale.
Expecting one to directly ground the other may have been a mistake about how scientific levels relate, not a failure of chemistry.
As Eric Scerri later acknowledged:
dependence does not imply derivability.
6. So Who Gave Whom an Impossible Job?
Not maliciously, but structurally:
Physics claimed ontological completeness.
Chemistry was told to “just apply it.”
The application required creating concepts the theory does not contain.
That is why quantum chemistry feels permanently provisional:
it is asked to do ontological work with tools that are not ontological.
7. The Clean Conclusion
Yes—in hindsight, chemists were implicitly asked to do something extraordinarily hard, and possibly impossible:
to recover chemically meaningful entities from a theory that does not contain them.
Chemists responded not by failing, but by quietly redefining success:
from conceptual derivation to predictive control.
The real mistake was not made by chemists,
but by the early belief—common in physics—that
having the fundamental laws automatically gives you the higher-level world.
H₂ showed, at the very first step, that this belief was wrong.
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