14 ideas
| 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) |
| 14794 | Instead of seeking Truth, we should seek belief that is beyond doubt [Peirce] |
| Full Idea: Your problems would be greatly simplified, if, instead of saying that you want to know the Truth, you were simply to say that you want to attain a state of belief unassailable beyond doubt. | |
| From: Charles Sanders Peirce (Essentials of Pragmatism [1905], I) | |
| A reaction: This is not the same as saying that belief beyond doubt IS truth. He is merely offering a strategy for scientists to side-step the sort of scepticism raised by Descartes and radical empiricists. |
| 14792 | A 'conception', the rational implication of a word, lies in its bearing upon the conduct of life [Peirce] |
| Full Idea: The present writer framed the theory that a 'conception', that is, the rational purport of a word or other expression, lies exclusively in its conceivable bearing upon the conduct of life. | |
| From: Charles Sanders Peirce (Essentials of Pragmatism [1905], I) |
| 14793 | The definition of a concept is just its experimental implications [Peirce] |
| Full Idea: If one can define accurately all the conceivable experimental phenomena which the affirmation or denial of a concept could imply, one will have therein a complete definition of the concept, and there is absolutely nothing more in it. | |
| From: Charles Sanders Peirce (Essentials of Pragmatism [1905], I) | |
| A reaction: Strictly, I would have thought you could only affirm or deny a complete proposition, rather than a concept. What should I do with the concept of a 'unicorn'? Note that all theories, such as empiricism or pragmatism, begin with an account of our concepts. |
| 21785 | We are only free, with rights, if we claim our freedom, and there are no natural rights [Hegel, by Houlgate] |
| Full Idea: Hegel says we are only truly free, and so bearers of rights, in so far as we claim our freedom. ...So there are no merely natural rights, and animal's have no rights. | |
| From: report of Georg W.F.Hegel (Lectures on the Philosophy of Right [1819], p.78) by Stephen Houlgate - An Introduction to Hegel 08 'Rights' | |
| A reaction: If there are no natural rights, then it is hard to see how claiming a right will create it. I can't create a right to drink the best champagne. It seems particularly unjust to deny rights to people so enslaved that freedom has never occurred to them. |
| 22041 | Representatives by region ignores whether they care about the national interest [Hegel, by Pinkard] |
| Full Idea: Selecting representatives on the basis of geography means selecting people without any regard to whether they represent the basic and important interests of the 'whole' of society. | |
| From: report of Georg W.F.Hegel (Lectures on the Philosophy of Right [1819]) by Terry Pinkard - German Philosophy 1760-1860 11 | |
| A reaction: Proportional representation seems to get away from this, but that can still be arranged according to large regions. Some means is needed to prevent the whole nation from exploitation a regional minority (such as Welsh speakers). |
| 21781 | The absolute right is the right to have rights [Hegel] |
| Full Idea: The absolute right is the right to have rights. | |
| From: Georg W.F.Hegel (Lectures on the Philosophy of Right [1819], p.127), quoted by Stephen Houlgate - An Introduction to Hegel 08 'Rights' | |
| A reaction: What a beautifully succinct and important idea! Does a foetus, or a dog, or a person in a vegetative state, or a slave, qualify? |