Logical Principle   

Logical Principle

Digital Companion to C. S. Peirce
Logical Principle
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1867 | On the Natural Classification of Arguments | W 2:24-25

every argument has, as portion of its leading principle, a certain principle which cannot be eliminated from its leading principle. Such a principle may be termed a logical principle.

An argument whose leading principle contains nothing which can be eliminated is termed a complete, in opposition to an incomplete, rhetorical, or enthymematic argument.

Since it can never be requisite that a fact stated should also be implied in order to justify a conclusion, every logical principle considered as a proposition will be found to be quite empty. Considered as regulating the procedure of inference, it is determinate; but considered as expressing truth, it is nothing.

1867-03-23 | The Logic Notebook | W 2:1

A purely contentless principle. As a logical principle should be.

1880 | On the Algebra of Logic | W 4:167-168; CP 3.166, 168

a leading principle, which contains no fact not implied or observable in the premisses, is termed a logical principle, and the argument it governs is termed a complete, in contradistinction to an incomplete, argument, or enthymeme.


A logical principle is said to be an empty or merely formal proposition, because it can add nothing to the premisses of the argument it governs, although it is relevant; so that it implies no fact except such as is presupposed in all discourse…

1898 | Cambridge Lectures on Reasoning and the Logic of Things: Types of Reasoning | RLT 132

a leading principle of maximum abstractness may be termed a logical principle.