Month: April 2026

Reverse-Engineering Quantum Mechanics, III.

An Option for the ‘Ground’ State

In previous posts we have encountered the three main equivalent re-formulations of classical (i.e., Newtonian) mechanics—Lagrangian, Hamiltonian, and Hamilton-Jacobi—as well as their quantum mechanical counterparts, Feynman path integrals, Heisenberg’s operator mechanics, and Schrödinger’s wave mechanics, respectively. (A few more are possible, cf. Styer et al. 2002, but these are the main ones of relevance here). We are now ready to think about what the final step ‘down’ might be to the quantum side of the bottom level of the ladder of abstraction, the quantum equivalent of the ‘ground’ from which classical mechanics arose.

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Reverse-Engineering Quantum Mechanics, II.

Coming Back Down Towards the ‘Ground’

The main contention of the previous post can be summed up succinctly as: the Schrödinger equation is to quantum mechanics what the Hamilton-Jacobi equation is to classical mechanics. This is because it was – in a sense – ‘derived’ (really inferred) from it, via the optical-mechanical analogy between idealised particle paths and idealised geometrical light rays, first pointed out by William Rowan Hamilton in the early 1830s (and see, e.g., Masoliver and Ros 2010 for a detailed mathematical exposition). The main postulate of Schrödinger’s wave mechanics was that the action $S$ from Hamilton-Jacobi mechanics becomes the phase of the complex wavefunction $\psi\sim e^{iS/\hbar}$. This meant that we therefore found ourselves three levels of abstraction away from, and ‘floating’ above (so to speak), the ‘ground’ that classical mechanics was founded upon, namely Newtonian mechanics in 3D space. This post now begins the process of thinking about how to come down again to seek a more solid footing, if indeed there is even one to find…

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‘The Sum Total of All Human Knowledge’, Part VII

Digital Zettelkasteneering

This post considers some of the issues that come up when trying to port a physical Zettelkasten (PZK) using the OoK+UDC schema into digital form (DZK) on a computer, as well as some use-cases for OoK indexing outside the context of a ZK.

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Reverse-Engineering Quantum Mechanics, I.

Generic Feynman Diagrams

‘The Coyote Problem’

I think I can safely say that nobody understands quantum mechanics.
— Richard Feynman, The Character of Physical Law (1967, p.129).

Six decades later, Feynman’s claim arguably still stands (and remember, he won the 1965 Nobel Prize in Physics for his work on quantum electrodynamics, including inventing those squiggly diagrams that everyone uses now; so, if he doesn’t understand it…). Despite a century of unprecedented empirical success, the interpretation of quantum mechanics still remains very contested. In general, it seems undertaking any attempt to try to actually make sense of it is “considered barely respectable at all, if not actively disparaged” (Carroll 2019, p.4). Multiple interpretations coexist—Copenhagen, Bohmian, Many Worlds, Objective Collapse, Quantum Bayesian and so forth, at least a dozen or so—each with committed proponents and unresolved difficulties. No consensus view has emerged. Quantum theory has taken on an almost mystical reputation, much of which is, frankly, arrant nonsense (Bricmont 2017).

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Of things NATO, 2: The Second Allied Foresight Conference, and beyond

Image of Emperor Marcus Aurelius statue in Rome

While the process of researching and writing the paper described in the previous post was going on, I was also in contact with another part of the strategic foresight branch at ACT who were beginning to co-organise the second allied foresight conference, thus fulfilling SACT General Lavigne’s wish from the 2024 Helsinki conference for these conferences to become a “tradition”. While that first conference in Helsinki was held in a hotel, which had certain security implications associated with it given the proximity of that city to a fairly staunch NATO adversary, the second one was being planned to be held at NATO Defense College in Rome, which is located inside a military base. Thus, security was going to be both more and less of an issue this time around.

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