16 ideas
| 15545 | Armstrong's analysis seeks truthmakers rather than definitions [Lewis] |
| Full Idea: I suggest that Armstrong has an unfamiliar notion of analysis, as not primarily a quest for definitions, but as a quest for truth-makers. | |
| From: David Lewis (Armstrong on combinatorial possibility [1992], 'The demand') | |
| A reaction: This is not a dichotomy, I think, but a shift of emphasis. A definition will probably refer to truthmakers; a decent account of truthmakers would approximate a definition. |
| 15546 | Predications aren't true because of what exists, but of how it exists [Lewis] |
| Full Idea: Predications seem, for the most part, to be true not because of whether things are, but because of how things are. | |
| From: David Lewis (Armstrong on combinatorial possibility [1992], 'The demand') | |
| A reaction: This simple point shows that you get into a tangle if you insist that truthmakers just consist of what exists. Lewis says Armstrong offers states of affairs as truthmakers for predications. |
| 15548 | Say 'truth is supervenient on being', but construe 'being' broadly [Lewis] |
| Full Idea: I want to say that 'truth is supervenient on being', but as an Ostrich about universals I want to construe 'being' broadly. | |
| From: David Lewis (Armstrong on combinatorial possibility [1992], 'Truth') | |
| A reaction: [His slogan is borrowed from Bigelow 1988:132-,158-9] This seems much more promising that the more precise and restricted notion of truthmakers, as resting on the existence of particular things. Presentism is the big test case. |
| 14399 | Presentism says only the present exists, so there is nothing for tensed truths to supervene on [Lewis] |
| Full Idea: Presentism says that although there is nothing outside the present, yet there are past-tensed and future-tensed truths that do not supervene on the present, and hence do not supervene on being. | |
| From: David Lewis (Armstrong on combinatorial possibility [1992], p.207) | |
| A reaction: Since I rather like both presentism and truth supervening on being, this observation comes as rather a devastating blow. I thought philosophy would be quite easy, but it's turning out to be rather tricky. Could tensed truths supervene on the present? |
| 10688 | 'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall] |
| Full Idea: 'Equivocation' is when the terms do not mean the same thing in the premises and in the conclusion. | |
| From: JC Beall / G Restall (Logical Consequence [2005], Intro) |
| 10690 | Formal logic is invariant under permutations, or devoid of content, or gives the norms for thought [Beall/Restall] |
| Full Idea: Logic is purely formal either when it is invariant under permutation of object (Tarski), or when it has totally abstracted away from all contents, or it is the constitutive norms for thought. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) | |
| A reaction: [compressed] The third account sounds rather woolly, and the second one sounds like a tricky operation, but the first one sounds clear and decisive, so I vote for Tarski. |
| 10691 | Logical consequence needs either proofs, or absence of counterexamples [Beall/Restall] |
| Full Idea: Technical work on logical consequence has either focused on proofs, where validity is the existence of a proof of the conclusions from the premises, or on models, which focus on the absence of counterexamples. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 10695 | Logical consequence is either necessary truth preservation, or preservation based on interpretation [Beall/Restall] |
| Full Idea: Two different views of logical consequence are necessary truth-preservation (based on modelling possible worlds; favoured by Realists), or truth-preservation based on the meanings of the logical vocabulary (differing in various models; for Anti-Realists). | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) | |
| A reaction: Thus Dummett prefers the second view, because the law of excluded middle is optional. My instincts are with the first one. |
| 10689 | A step is a 'material consequence' if we need contents as well as form [Beall/Restall] |
| Full Idea: A logical step is a 'material consequence' and not a formal one, if we need the contents as well as the structure or form. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) |
| 10696 | A 'logical truth' (or 'tautology', or 'theorem') follows from empty premises [Beall/Restall] |
| Full Idea: If a conclusion follows from an empty collection of premises, it is true by logic alone, and is a 'logical truth' (sometimes a 'tautology'), or, in the proof-centred approach, 'theorems'. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 4) | |
| A reaction: These truths are written as following from the empty set Φ. They are just implications derived from the axioms and the rules. |
| 10693 | Models are mathematical structures which interpret the non-logical primitives [Beall/Restall] |
| Full Idea: Models are abstract mathematical structures that provide possible interpretations for each of the non-logical primitives in a formal language. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 10692 | Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall] |
| Full Idea: There are many proof-systems, the main being Hilbert proofs (with simple rules and complex axioms), or natural deduction systems (with few axioms and many rules, and the rules constitute the meaning of the connectives). | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 15543 | How do things combine to make states of affairs? Constituents can repeat, and fail to combine [Lewis] |
| Full Idea: To me it is mysterious how a state of affairs is made out of its particular and universal constituents. Different states of affairs may have the very same constituents, and the existence of constituents by no means entails the existence of the states. | |
| From: David Lewis (Armstrong on combinatorial possibility [1992], 'What is there') | |
| A reaction: He is rejecting the structure of states of affairs as wholes made of parts. But then mereology was never going to explain the structure of the world. |
| 21227 | The Cogito demands a bridge to the world, and ends in isolating the ego [Velarde-Mayol] |
| Full Idea: All philosophies inspired in the Cogito have the problem of building a bridge from the starting point of consciousness to the external world. The result of this is the isolation and solitude of the very ego. | |
| From: Victor Velarde-Mayol (On Husserl [2000], 4.7.2) | |
| A reaction: This strikes me as a pretty good reason not to develop a philosophy which is inspired by the Cogito. |
| 21215 | The representation may not be a likeness [Velarde-Mayol] |
| Full Idea: Representationalism is the doctrine that maintains that the object is represented in consciousness by means of an image. ...One should not confuse an image with a likeness. | |
| From: Victor Velarde-Mayol (On Husserl [2000], 2.4.3) | |
| A reaction: Helpful reminder that sense-data or whatever may not be a likeness. But then how do they represent? Symbolic representation needs massive interpretation. |
| 21219 | Find the essence by varying an object, to see what remains invariable [Velarde-Mayol] |
| Full Idea: Eidetic Reduction consists of producing variations in the individual object until we see what is invariable in it. What is invariable is its essence or Eidos. | |
| From: Victor Velarde-Mayol (On Husserl [2000], 3.2.2) | |
| A reaction: This strikes me as an excellent idea. It more or less describes the method of science. Chemical atoms were thought to be unsplittable, until someone tried a new variation for dealing with them. |