Feynman’s ‘nobody understands quantum theory’ remains unchallenged. Curiously, you don’t need to understand it to use it. Our difficulties may be due to bias toward an ultimate mechanical theory. This essay offers a map to a fresh perspective. The Clausius-Boltzmann-Gibbs mechanical thermodynamics is inherently incomplete. Quantum theory, indeed, all of physics, is embedded in thermodynamics. Yet quantum theory is not a classical mechanical theory. Here then is our core problem: how to understand quantum theory thermodynamically without the mechanical presuppositions. The solution proposed is that quantum theory is properly understood only in terms of engineering thermodynamics. The implications are exciting.

There is a longstanding problem of making sense of quantum theory.
Feynman’s assertion, “I think I can safely say that nobody understands quantum
mechanics” remains unchallenged. Yet, experimentalists tell us quantum
mechanics is the most successful theory in history. One experimental physicist
colleague noted that, ‘I don’t need to understand it to be able to use it.’
Per hypothesis, the difficulties in understanding quantum theory arise
because it is not a classical type of theory, as Bohr, Heisenberg and Pauli
emphasized.The failure to make sense of quantum theory is most simply the
failure to make sense of it within the framework defined by the presuppositions of
classical symmetry and conservation.
To make progress it is helpful to distinguish between quantum theory and
quantum mechanics. What is new and different in quantum theory is that it arose
through the ‘interpolation’ of two complementary classical mechanical theories,
Newtonian particle mechanics and Maxwellian wave mechanics. Consequently,
quantum theory is ‘mechanically ambiguous’ as represented by the famous two-slit
experiment. You can choose to observe the particle phenomena, or you can choose
to observe the wave phenomena. What you observe depends on your choice of
experimental setups. Quantum theory pushes us beyond the classical notion of ‘the
one right way’ to observe an unambiguous ‘objective’ reality.
And yet, applying quantum theory in different experimental settings, in
different ways, with different constraints has been enormously successful.
Quantum theory wants us to understand reality in a new way. Reality isn’t
just particles and it isn’t just waves, it is both and yet, neither exclusively.
Quantum theory also moves us from an ‘observing spectator’ to an ‘active
participant’ in reality.