John, Jon A.S., Phyllis et al., JFS: Nobody today makes a distinction between a logica utens (using) vs a logica docens (teaching).
GF: It may well be that nobody outside of Peircean studies uses those terms, which Peirce took from the Scholastic philosophers. And it may be that the distinction itself is not commonly made in your particular field, John. But the distinction is a crucial one in cognitive science and related disciplines. It is essentially the distinction between a "logic" that operates implicitly and an explicitly formulated "logic" (often one which aims to explicate the "logic" which functions implicitly). It is precisely analogous to the difference between semiosis and semiotics. In cognitive science it is sometimes referred to as the "use/mention" distinction. See Comminding (TS <https://gnusystems.ca/TS/css.htm#implex> .14) (gnusystems.ca) for more on this; also https://gnusystems.ca/TS/css.htm#x14 for a Peirce quote which makes the distinction without using the Scholastic terms. For more evidence that this is the distinction Peirce denotes by using those terms, see Logica Utens | Dictionary | Commens <http://www.commens.org/dictionary/term/logica-utens> . For example, he says that "In everyday business, reasoning is tolerably successful; but I am inclined to think that it is done as well without the aid of theory as with it. A Logica Utens, like the analytical mechanics resident in the billiard player's nerves, best fulfills familiar uses" (CP 1.623, EP2:30). Since Peirce's phaneroscopy eschews prior theorizing while it generalizes from observation of familiar experience, it seems clear to me that any logic it uses must be a logica utens. Formulating that logic is the task of logical theory, i.e. logica docens. The reason that phaneroscopy can draw on mathematical logic is that the logic of mathematics is a logica utens, as Peirce said c. 1896. It operates prior to formulation. Hence the ambiguity of "formal logic," which, if it can denote an implicitly functioning logic, can also denote a range of explicit theories of logic formulated mathematically. That's why I think it confusing to refer to the "logic" which is "resident in the phaneroscopist's nerves" as "formal logic." Gary f. From: peirce-l-requ...@list.iupui.edu <peirce-l-requ...@list.iupui.edu> On Behalf Of sowa @bestweb.net Sent: 11-Sep-21 20:53 Nobody today makes a distinction between a logica utens (using) vs a logica docens (teaching). And nobody today claims that a formal logic (either Peirce's algebraic notation or his existential graphs) is inappropriate for calculation. In fact, Frege made exactly the same mistake. Neither Peirce nor Frege had any experience with the long and complicated proofs that became common in the century that followed their discoveries. Even Whitehead and Russell, who adopted Frege's rules of inference, did not consider their proof methods to be efficient for computation. But much better proof procedures were discovered in the century after Peirce, and the search for better algorithms accelerated when digital computers became available. Gerhard Gentzen (1936) invented several important methods that were adapted to computer processing. But the simplicity of Peirce's EG rules are a major improvement over Gentzen's methods. In fact, they are so simple and elegant that they enabled an unsolved research problem from 1988 to be solved as a simple corollary in terms of Peirce's rules. For an overview of these issues, see the slides I presented at an APA conference, session on Peirce in April 2015: http://jfsowa.com/talks/ppe.pdf Slide two of ppe.pdf has a link to a 76-page article in the Journal of Applied Logic, in which I spell out all the details. John
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