Sigmund Freud

Sigmund Freud (1856–1939), the founder of psychoanalysis, enters this vault not as a subject in his own right but as a piece of vocabulary that keeps crossing domains. His psychiatric use of "neurosis," and his energetic model of the mind (cathexis, psychic energy), recur in two otherwise unrelated threads — which is exactly the kind of cross-domain lexical migration the vault exists to surface.

The two threads:

1. Occupational medicine. Freud's contemporaneous psychiatric "neurosis" is the term whose collision with Gowers's neurological "occupational neurosis" one historian (Pritchard) credits for repetitive-strain injury's reclassification as psychological — a mechanism a second historian (Quintner) does not invoke.
2. The origins of backpropagation. Paul Werbos reports, in his own account, building backpropagation to translate Freud's "psychic energy" into derivative equations, mapping cathexis onto the derivative.

The connective interest is that "neurosis"/Freudian vocabulary is doing load-bearing work in two fields the vault otherwise treats as strangers — a candidate cross-domain bridge worth a dedicated pass rather than a claim.

References

• claim-pritchard-2013-attributes-writers-cramp-psychologization-to-gowers-freud-neurosis-collision — the Gowers–Freud terminology-collision argument.
• claim-quintner-frames-occupation-neurosis-as-19c-cns-diagnosis-without-freud-collision — the competing account that omits the Freud mechanism.
• claim-werbos-backprop-from-freud-own-account — Werbos built backpropagation to translate Freud's psychic energy into derivatives.
• claim-werbos-2011-cathexis-derivative-mapping — Werbos's explicit cathexis-as-derivative mapping.