| 11863 | (λx)[Man x] means 'the property x has iff x is a man'. [Wiggins] |
| Full Idea: The Lambda Abstraction Operator: We can write (λx)[Man x], which may be read as 'the property that any x has just if x is a man'. | |
| From: David Wiggins (Sameness and Substance Renewed [2001], 4.2) | |
| A reaction: This technical device seems to be a commonplace in modern metaphysical discussions. I'm assuming it can be used to discuss properties without venturing into second-order logic. Presumably we could call the property here 'humanity'. |
| 11176 | The property of Property Abstraction says any suitable condition must imply a property [Fine,K] |
| Full Idea: According to the principle of Property Abstraction, there is, for any suitable condition, a property that is possessed by an object just in case it conforms to the condition. This is usually taken to be a second-order logical truth. | |
| From: Kit Fine (Senses of Essence [1995], §4) | |
| A reaction: Fine objects that it is implied that if Socrates is essentially a man, then he essentially has the property of being a man. Like Fine, I think this conclusion is distasteful. A classification is not a property, at least the way most people use 'property'. |
| 9725 | 'Predicate abstraction' abstracts predicates from formulae, giving scope for constants and functions [Fitting/Mendelsohn] |
| Full Idea: 'Predicate abstraction' is a key idea. It is a syntactic mechanism for abstracting a predicate from a formula, providing a scoping mechanism for constants and function symbols similar to that provided for variables by quantifiers. | |
| From: M Fitting/R Mendelsohn (First-Order Modal Logic [1998], Pref) |
| 11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
| Full Idea: λ-abstraction can be used to abstract and disambiguate a predicate. De re is [λx◊P(x)](f) - f has the possible-P property - and de dicto is ◊[λxP(x)](f) - possibly f has the P-property. Also applies to □. | |
| From: Melvin Fitting (Intensional Logic [2007], §3.3) | |
| A reaction: Compare the Barcan formula. Originated with Church in the 1930s, and Carnap 1947, but revived by Stalnaker and Thomason 1968. Because it refers to the predicate, it has a role in intensional versions of logic, especially modal logic. |
| 13703 | λ can treat 'is cold and hungry' as a single predicate [Sider] |
| Full Idea: We might prefer λx(Fx∧Gx)(a) as the symbolization of 'John is cold and hungry', since it treats 'is cold and hungry' as a single predicate. | |
| From: Theodore Sider (Logic for Philosophy [2010], 5.5) |