Today I came across this passage at W5.239-240 (1885), which offers a different take on the categoriality of Rule/Case/Result in deduction.
CSP: The most rudimentary kind of inference is exemplified by the *Cogito, ergo sum*. If this be an inference at all, it must recognize itself as proceeding according to some rule,--for that is precisely what the *ergo* implies,--and this rule may be stated as "Si cogito, sum." Thus the inference is brought to the form of a *Consequentia* or Modus ponens. Si cogito, sum. Cogito. Ergo, sum. Here there are three propositions. *Cogito *is the fact originally observed and *quasi* free, that is, unnecessitated, undeduced; therefore the *first*. Sum is the fact that follows, that is necessitated, the *Second*. Si cogito sum is the fact which brings the other two into relation, the medium or *Third*. Rule is still 3ns, but here Case is 1ns and Result is 2ns--as I have suggested previously for abduction--rather than the other way around. In Gary R.'s notation ... 2nd (1ns) Cogito. |> 1st (3ns) Si cogito, sum. 3rd (2ns) Ergo, sum. I am not arguing anything on this basis, just calling attention to it as another data point. Regards, Jon Alan Schmidt - Olathe, Kansas, USA Professional Engineer, Amateur Philosopher, Lutheran Layman www.LinkedIn.com/in/JonAlanSchmidt - twitter.com/JonAlanSchmidt
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