|Practical inference: practical conclusions go from an idea, a wish, or a statement, and lead to an intention of action. Practical conclusions lead to a weaker justification than extended normative conclusions. (See C. Beisbart, “Handeln Begründen, Motivation, Rationalität, Normativität“, Münster, 2007, p. 223)._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. |
Practical Inference/Kenny/Geach: indicative inference: here the addition of a premise from a valid inference cannot make an invalid (and also not by the absence of one of several premises). - On the other hand, imperative inference: here, added premises may very well make a valid inference an invalid! Commands must be consistent with each other.
Practical Inference/Kenny/Geach: Surprising result: in practical concluding, the command FKpq is not deductively equivalent to the pair Ep, Eq. - This is not really paradox: the equivalence would lead to an absurd result because for the same reason, the set Fp, Fq, Fr ... would be deductively equivalent to FKpKqKr ... but this latter command could only be fulfilled if it was guaranteed that all our wishes could be fulfilled at the same time - so we need further inference rules for practical inference._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution.
Logic Matters Oxford 1972