Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.

Class IV. Words Relating to the Intellectual Faculties
Division (I) Formation of Ideas
Section IV. Reasoning Processes

476. Reasoning.

   NOUN:REASONING; ratiocination, rationalism; dialectics, dialecticism, induction, generalization.
  DISCUSSION, comment; ventilation; inquiry [See Inquiry].
  ARGUMENTATION, controversy, debate; polemics, wrangling; contention [See Contention]; logomachy, disputation, disceptation [archaic]; paper war.
  LOGIC, art of reasoning.
  process -, train -, chain- of reasoning; deduction, induction; synthesis, analysis.
  argument; case, plea, plaidoyer [F.], opening; premise or premiss; lemma, proposition, terms, premises; postulate, data, starting point, principle; inference (judgment) [See Judgment].
  prosyllogism, syllogism; enthymeme, sorites, dilemma, a fortiori reasoning, a priori reasoning, reductio ad absurdum [L.], horns of a dilemma, argumentum ad hominem [L.], comprehensive argument; empirema, epagoge.
  LOGICAL SEQUENCE; good case; correct -, just -, sound -, valid -, cogent -, irrefutable -, logical -, forcible -, persuasive -, persuasory [rare] -, consectary [obs.] -, conclusive [See Demonstration] -, subtle- reasoning; force of argument; strong -point, – argument.
  ARGUMENTS, reasons, pros and cons.
  REASONER, logician, dialectician; disputant; controversialist, controvertist; wrangler, arguer, debater, polemic, casuist, rationalist; scientist; eristic.
   VERB:REASON, argue, discuss, debate, dispute, wrangle; argufy or argify [dial.], bandy -words, – arguments; chop logic; hold -, carry on- an argument; controvert (deny) [See Negation]; canvass; comment -, moralize- upon; consider (examine) [See Inquiry].
  TRY CONCLUSIONS; open a -discussion, – case; join -, be at- issue; moot; come to the point; stir -, agitate -, ventilate -, torture- a question; take up a -side, – case.
  CONTEND, take one’s stand upon, insist, lay stress on; infer [See Judgment].
  FOLLOW FROM (demonstration) [See Demonstration].
   ADJECTIVE:REASONING &c. v.; rational, ratiocinative, rationalistic; argumentative, controversial, dialectic, polemical; discursory, discursive; disputatious; logomachic or logomachical; Aristotelian, eristic or eristical.
  DEBATABLE, controvertible.
  LOGICAL; syllogistic, soritical, epagogic, inductive, deductive, synthetic or synthetical, analytic or analytical; relevant [See Agreement].
   ADVERB:FOR, because, hence, whence, seeing that, since, sith [archaic], then, thence, so; for -that, – this, – which- reason; for as much as or forasmuch as, in as much as or inasmuch as; whereas, ex concesso [L.], considering, in consideration of; therefore, argal [archaic], wherefore; consequently, ergo [L.], thus, accordingly; a priori [L.]; a fortiori [L.].
  FINALLY, in conclusion, in fine; after all, au bout du compte [F.], on the whole, taking one thing with another; pro and con; rationally &c. adj.
  1. Ab actu ad posse valet consecutio.
  2. Per troppo dibatter la verità si perde.
  3. Troppo disputare la verità fa errare.
  4. Remembrance and reflection, how allied; What thin partitions sense from thought divide.—Pope
  5. And many a Knot unravelled by the Road, But not the Master-knot of Human Fate.—Omar Khayyám—Fitzgerald
  6. Logic is mainly valuable wherewith to exterminate logicians.—Chesterton