The Commens Dictionary

Quote from ‘Pragmatism’


The […] supposition is that an association has already been established in the reasoner’s mind of such strength that to think that any object is a man immediately leads without question to thinking that he died at some date in the past or will die on some future day. Now to the reasoner, imbued with that habit of thought, there comes this discovery that some being, known to him as Socrates, is a man. This acts suggestively to make him think that Socrates, if not already dead, will surely some day die. The logic-books call that “reasoning.” They even say that it presents the type of reasoning. It is plainly nothing in the world but associative suggestion; yet since calling it “reasoning,” or ratiocination, has the sanction of ages, we must accept that terminology. Machines have actually been constructed that will perform that reasoning, and much more that is less obvious to an ordinary mind. In working these machines, I may say, without tying myself to detailed accuracy, you do that which is, in effect, to put the cards into a Jacquard loom severally expressive of the premisses; whereupon, upon turning the crank, out pops the conclusion. Let pitiably unformed or degraded intelligences see some dark mysteries in this. My reader will exclaim, “Fine business, truly, for the godlike faculty of reason, to be pitted against a machine!” The traditions of language so enslave us that this mere action of suggestion must receive the high title of reasoning; but let me be permitted at any rate to discriminate it as “corollarial” reasoning… [—]

In corollarial reasoning, the premisses act as stimulus to a suggestion according to general logical associations. But in theoric demonstration, it is necessary that associations should be introduced of which the premisses afford not the slightest hint.

MS [R] 318:48-9, 55
‘Corollarial Reasoning’ (pub. 13.10.15-17:50). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from
Oct 13, 2015, 17:50 by Mats Bergman
Last revised: 
Oct 13, 2015, 18:03 by Mats Bergman