John Stuart Mill

English philosopher and logician (1806–1873), author of A System of Logic (1843). He enters the wiki as the chief named target of Husserl's Prolegomena (husserl-1900-logical-investigations-vol1) — the paradigm of "extreme, consistent psychologism" — and a recurring foil across Investigations I–II. Husserl nonetheless starts from Mill where it suits him: the Investigations' Introduction quotes Mill approvingly on language as the necessary threshold of logic.

Key Points

  • The psychologistic thesis in his words: logic "owes all its theoretical foundations to psychology" (quoted Prol. §17) — the position the whole Prolegomena dismantles.
  • The law of contradiction empiricized (Prol. §§25–26): for Mill "one of our earliest and most familiar generalizations from experience," grounded in the incompatibility of belief and disbelief as mental states. Husserl's verdict: the cited "facts" (light/darkness, sound/silence) "are not contradictory propositions at all," and the psychologized law is "a wholly vague, and scientifically unproven, empirical proposition" — its restriction to "normal individuals of the genus homo" exposing it to the insane-judger, hypnosis, and delirium tests. The Appendix generalizes: extreme empiricism "destroys the possibility of the rational justification of mediate knowledge, and so destroys its own possibility."
  • Proper names (Inv I §16): Mill's non-connotative names, modeled on the robber's chalk-mark (Arabian Nights), confuse indicating with expressing — "the chalk-mark of the robber is a mere indication, while a proper name is an expression… it is of the essence of an index to point to… an existence, whereas the object named need not be taken to exist at all." Denotation/connotation must not be mapped onto naming/meaning.
  • Abstraction as attention (Inv II §§13–14, 21): Mill's attention-theory (borrowed from Hamilton) is nominalism about concepts; his "unconsciousness of the determinations that we abstract from is a useless, strictly speaking an absurd fiction." Against Spencer he defends the "identity" of attributes — then reduces attributes to "the resemblances of our sensations," which "presupposes what it should explain away" (§5: the identical one-in-many).
  • The approved threshold (Inv. Intro §1): "language is one of the principal instruments or helps of thought" — Husserl endorses beginning logic with language while refusing to end there.

Connections

  • is the paradigm of psychologism — the Prolegomena's standing example of the empiricist wing.
  • is refuted in detail by expression-and-indication (proper names) and ideal-species (attention-theory of abstraction; the Mill–Spencer controversy).
  • contrasts with evidenz — his "philosophy of evidence" is the feeling-theory §51 replaces.

Open Questions

  • Mill's utilitarianism and political philosophy are untouched by this corpus — this page is logic-only until further sources arrive.

Sources

  • husserl-1900-logical-investigations-vol1 — Prol. §§1, 17 (the thesis), §§25–26 + Appendix (contradiction; self-cancellation), §§38, 49 (extreme psychologism; philosophy of evidence); Inv. Intro §1 (the approved starting point); Inv I §16 (proper names); Inv II §§5, 13–14, 21 (attention-theory; Mill–Spencer). Extraction note D1.14–D1.15, D4.11, D5.5, D5.10, D5.14.