Glossary — The First Principle

Plain restatements, in the order of the alphabet rather than of the argument. Each term was taught at first use; this list is a courtesy, not a prerequisite.

Abduction.: Reasoning backwards from an observation to what would best explain it; honest exactly insofar as its verdicts cash into prior plausibility and predictive fit.
Agent (A).: Whatever performs an inference: holds representations, follows the rules, engages the content. Requires no consciousness.
Approximation.: Deviation from exact consistency that a finite reasoner tracks, bounds, and reports; the same shortfall presented as a full conclusion, knowingly or not, is smuggling.
Channel.: Any path by which evidence reaches a reasoner: perception, memory, testimony, instrument, model. Each has a reliability, and each can be corrupted.
Channel-grade.: The standing a source earns when its track record obliges a consistent reasoner to weight it at least as heavily as the best human channels in a domain.
Constitutive.: True of an activity by definition of the activity, as diagonal movement is of bishops; contrasted with hypothetical connections the world might have withheld.
Constraint.: What you are given: evidence, logic, the stated structure of a problem. Conclusions are what constraints determine.
Credal set.: The full family of MU-consistent belief-distributions the constraints permit, held whole when they determine no single one.
Credence.: Degree of belief, from impossible to certain.
Doxa.: Graded, revisable, evidence-proportioned belief; the correct state for nearly everything, and not a failed version of anything.
Epistēmē.: Belief immune to any possible evidence: the ground itself, and the truths of logic and mathematics given their axioms; almost nothing else.
Epistemic zero.: MU as the additive identity of belief: the principle that adds nothing, and by adding nothing makes the architecture possible.
Falsifiability.: The requirement that a claim forbid something; a claim compatible with every observation teaches nothing.
Inference.: Drawing conclusions from constraints.
Likelihood.: How strongly a hypothesis predicts the evidence actually seen.
Logic (L).: The rules component of inference; MU requires that some rules govern without decreeing which system.
Maximum entropy.: Spreading credence as widely as the constraints allow; the least-assuming starting point, made exact.
MU.: Two claims under one name, and the book keeps them apart. The fact: consistent inference is possible, which cannot be coherently denied. The discipline: assume nothing beyond what the constraints demand, which is what inference requires of anyone who undertakes it, argued as a constitutive norm rather than proved as a logical truth. Also the koan syllable: the lawful refusal of a question’s false frame.
Prior.: Your credence before a given piece of evidence arrives.
Realizability.: The truth’s presence within the space of hypotheses you are entertaining; a condition of convergence, and a demand on imagination.
Resolute completion.: When a forced bet demands one number, the least-assuming admissible member of the credal set, kept fixed rather than re-chosen when the payoffs shift.
Resonance.: A cross-tradition parallel of discipline without shared formal content; this book’s default and deliberate modesty.
Smuggling.: Content appearing in conclusions that the constraints never paid for; the book’s central crime.
Teiku.: The Talmud’s mark for a question honestly fought to a standstill: let it stand.
Threshold.: The stakes-calibrated level of doxa at which, for a given purpose, one acts as if; a practical instrument, never an epistemic fact.
Update rule.: The unique consistent rule within the stated prior, constraint, and consistency-condition scope; the one way to move credence when constraints arrive.