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Notes on Logic:

Informal, Deductive, and Inductive

Secundum quid

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I was browsing through an old philosophy vocabulary book and reached the following entry:
Fallacy--Fallacia a Dicto Secundum quid ad Dictum Simpliciter, when a term is used, in one premiss, in a limited, and in the other in an unlimited sense; as, the Ethiopioan is white as to his teeth, therefore he is white.
(Charles P. Krauth, A Vocabulary of the Philosophical Sciences, (New York: Sheddon & Company, 1879), 192.)

Fifty years later, a popular logic book discussed the fallacy in this manner:
A dicto simpliciter ad dictum secundum quid ... arguing from a general rule to a special case, without allowing for the special circumstances... A dicto secundum quid ad dictum simpliciter. This is the converse of the preceding type of fallacy, and consists in arguing from what holds good in special circumstances to a general rule in which those circumstances are ignored. For example, the fact that certain things (e.g., the destruction of enemy life and property, etc.) are allowed in the special circumstances of warfare, is no ground for allowing them in peace time.
(A. Wolf, Textbook of Logic (London: George Allen & Unwin Ltd., 1930), 361-362.)

Amazing! In the first quotation from Krauth, we have an instance of what is usually called the fallacy of Composition, and in the second quotation from Wolf, we have an instance of what is usually called hasty generalization.

Interestingly enough, Charles P. Krauth, in the 1879 volume, decscribes Wolf's A dicto secundum quid ad dictum simpliciter as Fallacia Accidentis (Krauth, 191)!

The distinction between hasty generalization and Composition was outlined earlier in this blog under the topic of Generalities and Specificities in Inference. It seems to me I recall one or two current logic textbooks making a similar confusion.

It may well be that the Secundum quid fallacies historically conflated hasty generalization and Composition and conflated the fallacies of Accident and Division, also. Yet, A. Wolf in the second book quoted above lists Accident separately as belonging to the category of "Verbal Fallacies" and the Secundum quid's as "Non-Verbal Fallacies," which seems to me to be entirely correct only if Secundum quid is interpreted with respect to parts and wholes.

I'm also curious about textbooks in the sciences, especially biology, handle these reasoning processes. It seems to me almost every college biology textbook on the market gets the distinction between deduction and induction wrong. I would guess, as well, there might be some confusion between hasty generalization and Composition since both processes are fruitful sources of first hypotheses in the science of discovery.

Inductive Arguments and True ConclusionsAd Hominem and Insults

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