Quantum Chemistry: Success or Failure?

Chemistry as the science of molecules is based on Quantum Mechanics as the science of atoms forming the 250 million known molecules by chemical bonding. In other words, the theoretical/computational foundation of Chemistry is Quantum Chemistry QC, since there is no alternative.  

Let us seek an evaluation of the functionality of QC in this role. We let chatGPT collect some views (references below): 

• Quantum mechanics does not contain chemical structure or bonding in its ontology, so chemistry is not reducible to physics even in principle. (Primas 1981)
• The exact quantum‐mechanical description of matter contains no molecules or structures at all; these appear only through approximations such as the Born–Oppenheimer separation. (Woolley & Sutcliffe 2012) 
• Molecular structure is not part of the ontology of quantum mechanics and emerges only through symmetry breaking and modeling, not derivation from the fundamental theory. (Hendry 2010)
• Although chemistry depends on quantum mechanics, key chemical concepts such as bonding and periodicity cannot be derived from it, so reduction fails conceptually even if physical dependence holds. (Scerri 2007)
• Core chemical concepts like bond and structure do not correspond to entities in quantum mechanics and therefore cannot be reduced to physical descriptions. (van Brakel 2000)
• Chemical phenomena such as reactions and transformations are not definable in physical terms, showing that quantum theory predicts outcomes without providing chemical explanations. (Needham 2008)
• There is no operator or unique quantity in quantum mechanics corresponding to the chemical bond, making the bond a model-dependent construct rather than a fundamental entity. (Shaik & Hiberty 2007)
• The exact quantum‐mechanical treatment of molecules is not only computationally intractable; it is also chemically uninformative. The representations that make quantum mechanics useful in chemistry are not derived by straightforward solution of the Schrödinger equation, but by introducing approximations and conceptual structures that are not part of the fundamental theory. (Woody 2000)
• Quantum chemistry is empirically powerful but fails to conceptually ground molecules, bonds, and structure in its own ontology, so it cannot serve as a foundational explanation of chemistry despite its predictive success. (Summary by chatGPT)

What can we learn from this? That QC is a success as theoretical/computational foundation of Chemistry? Is it possible to twist the above statements indicating failure, into success? After all, QC takes massive super-computer resources. 

In this situation of apparent failure, RealQM offers an alternative foundation with theory directly translated to computer code with linear complexity, see this article submitted to Foundations of Chemistry.

Here is a comment to the post by chatGPT:

• This gets to a real weakness of quantum chemistry: the exact Schrödinger equation does not actually produce molecules, bonds, or reactions in any chemically meaningful way. All the structure chemists care about only appears after imposing strong approximations (Born–Oppenheimer, orbitals, potential surfaces, damping, etc.) that are not part of the fundamental theory. As Andrea Woody and others have argued, the exact quantum description is not just intractable but chemically uninformative. In that sense, quantum chemistry “works” only by departing from the very framework it is supposed to be based on.

Here is what chatGPT delivers when asked to defend against the above views:

• The criticism confuses foundational purity with scientific success. It’s true that the bare Schrödinger equation does not hand us bonds, orbitals, or reaction pathways in closed form—but no physical theory does that for complex systems without modeling, idealization, and coarse-graining. What matters is whether those approximations are physically grounded and empirically reliable. In quantum chemistry they are: from Hartree–Fock and post-HF to DFT and ab initio dynamics, the framework routinely predicts structures, spectra, reaction energies, and mechanisms with quantitative accuracy verified against experiment. That is not a philosophical afterthought—it is the core of how modern chemistry, materials science, and drug design actually work. So quantum chemistry does not “fail”; it succeeds precisely because it shows how rich chemical behavior emerges from quantum laws when treated with disciplined, testable approximations.

Your choice? Note that even in defence mode is it acknowledged that bonds and reaction pathways of prime interest, are not handed. 

I then ask if Philosophy of Chemistry PC can resolve the opposing views of critique and defence and get this response: 

• Philosophy of chemistry does not “fix” the disagreement by choosing a winner, but by showing that the two views use different standards of success. The critics are right that chemistry is not strictly reducible to the bare Schrödinger equation: chemical concepts, structures, and reactions are not derivable without strong approximations and representational choices. But defenders are equally right that quantum chemistry is an extraordinary scientific success, because those approximations are physically motivated, systematically improvable, and empirically validated.

• Philosophy of chemistry resolves the apparent contradiction by reframing it: quantum chemistry fails as a literal, foundational reduction, yet succeeds as an effective, unifying, and predictive theory. What it cannot do—and should not try to do—is eliminate the need for modeling, idealization, and emergence in complex systems. The tension is not a flaw in chemistry, but a feature of how science actually connects fundamental laws to higher-level phenomena.

It seems that the role of PC is to make the devastating critique acceptable into a business as usual.

References: 

• Primas, H. (1981). Chemistry, Quantum Mechanics and Reductionism. Springer.
• Sutcliffe, B. T., & Woolley, R. G. (2012). “On the quantum theory of molecules.” Journal of Chemical Physics, 137, 22A544.
• Hendry, R. F. (2010). “Molecular structure and the philosophy of chemistry.” In Philosophy of Chemistry (Scerri & McIntyre, eds.).
• Scerri, E. R. (2007). The Periodic Table: Its Story and Its Significance. Oxford University Press.
• van Brakel, J. (2000). The Philosophy of Chemistry. Leuven University Press.
• Needham, P. (2008). “What is the problem with reduction?” Studies in History and Philosophy of Modern Physics, 39(4), 763–776.
• Shaik, S., & Hiberty, P. C. (2007). A Chemist’s Guide to Valence Bond Theory. Wiley.
• Woody, A, (2000). Putting Quantum Mechanics to Work in Chemistry: The Power of Diagrammatic Representation, Philosophy of Science 67.