7 ideas
10779 | A comprehension axiom is 'predicative' if the formula has no bound second-order variables [Linnebo] |
Full Idea: If φ contains no bound second-order variables, the corresponding comprehension axiom is said to be 'predicative'; otherwise it is 'impredicative'. | |
From: Øystein Linnebo (Plural Quantification Exposed [2003], §1) | |
A reaction: ['Predicative' roughly means that a new predicate is created, and 'impredicative' means that it just uses existing predicates] |
10781 | A 'pure logic' must be ontologically innocent, universal, and without presuppositions [Linnebo] |
Full Idea: I offer these three claims as a partial analysis of 'pure logic': ontological innocence (no new entities are introduced), universal applicability (to any realm of discourse), and cognitive primacy (no extra-logical ideas are presupposed). | |
From: Øystein Linnebo (Plural Quantification Exposed [2003], §1) |
10783 | Plural quantification depends too heavily on combinatorial and set-theoretic considerations [Linnebo] |
Full Idea: If my arguments are correct, the theory of plural quantification has no right to the title 'logic'. ...The impredicative plural comprehension axioms depend too heavily on combinatorial and set-theoretic considerations. | |
From: Øystein Linnebo (Plural Quantification Exposed [2003], §4) |
10778 | Can second-order logic be ontologically first-order, with all the benefits of second-order? [Linnebo] |
Full Idea: According to its supporters, second-order logic allow us to pay the ontological price of a mere first-order theory and get the corresponding monadic second-order theory for free. | |
From: Øystein Linnebo (Plural Quantification Exposed [2003], §0) |
10782 | The modern concept of an object is rooted in quantificational logic [Linnebo] |
Full Idea: Our modern general concept of an object is given content only in connection with modern quantificational logic. | |
From: Øystein Linnebo (Plural Quantification Exposed [2003], §2) | |
A reaction: [He mentions Frege, Carnap, Quine and Dummett] This is the first thing to tell beginners in modern analytical metaphysics. The word 'object' is very confusing. I think I prefer 'entity'. |
7566 | The Identity of Indiscernibles is really the same as the verification principle [Jolley] |
Full Idea: Various writers have noted that the Identity of Indiscernibles is really tantamount to the verification principle. | |
From: Nicholas Jolley (Leibniz [2005], Ch.3) | |
A reaction: Both principles are false, because they are the classic confusion of epistemology and ontology. The fact that you cannot 'discern' a difference between two things doesn't mean that there is no difference. Things beyond verification can still be discussed. |
1556 | By nature people are close to one another, but culture drives them apart [Hippias] |
Full Idea: I regard you all as relatives - by nature, not by convention. By nature like is akin to like, but convention is a tyrant over humankind and often constrains people to act contrary to nature. | |
From: Hippias (fragments/reports [c.430 BCE]), quoted by Plato - Protagoras 337c8 |