display all the ideas for this combination of philosophers
3 ideas
22017 | Normativity needs the possibility of negation, in affirmation and denial [Fichte, by Pinkard] |
Full Idea: To adopt any kind of normative stance is to commit oneself necessarily to the possibility of negation. It involves doing something correctly or incorrectly, so there must exist the possibility of denying or affirming. | |
From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Terry Pinkard - German Philosophy 1760-1860 05 | |
A reaction: This seems to be the key idea for understanding Hegel's logic. Personally I think animals have a non-verbal experience of negation - when a partner dies, for example. |
5740 | Second-order logic needs second-order variables and quantification into predicate position [Melia] |
Full Idea: Permitting quantification into predicate position and adding second-order variables leads to second-order logic. | |
From: Joseph Melia (Modality [2003], Ch.2) | |
A reaction: Often expressed by saying that we now quantify over predicates and relations, rather than just objects. Depends on your metaphysical commitments. |
5741 | If every model that makes premises true also makes conclusion true, the argument is valid [Melia] |
Full Idea: In first-order predicate calculus validity is defined thus: an argument is valid iff every model that makes the premises of the argument true also makes the conclusion of the argument true. | |
From: Joseph Melia (Modality [2003], Ch.2) | |
A reaction: See Melia Ch. 2 for an explanation of a 'model'. Traditional views of validity tend to say that if the premises are true the conclusion has to be true (necessarily), but this introduces the modal term 'necessarily', which is controversial. |