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) |
| 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 |
| 9758 | To make sense of personal identity, focus on agency rather than experience [Korsgaard] |
| Full Idea: A focus on agency makes more sense of personal identity than a focus on experience. | |
| From: Christine M. Korsgaard (Intro to 'Creating the Kingdom of Ends' [1996], §2) | |
| A reaction: This strikes me as eminently sensible advice for the beginning of any discussion of personal identity. Her personal bęte noir is Parfit, who focuses on what we are conscious of. |
| 9757 | A person viewed as an agent makes no sense without its own future [Korsgaard] |
| Full Idea: In forming a particular plan of life, you need to identify with your future in order to be what you are even now. When the person is viewed as an agent, no clear content can be given to the idea of a merely present self. | |
| From: Christine M. Korsgaard (Intro to 'Creating the Kingdom of Ends' [1996], §2) | |
| A reaction: I certainly like the notion that we should treat persons primarily as agents, since I take personhood to be more like a process than an existent entity. If a large brick is about to hit you, you actually have no future, though you think you have. |
| 9759 | Theory of action focuses on explanation and prediction; practical action on justification and choice [Korsgaard] |
| Full Idea: When we look at our actions from the theoretical standpoint our concern is with their explanation and prediction. When we view them from the practical standpoint our concern is with their justification and choice. | |
| From: Christine M. Korsgaard (Intro to 'Creating the Kingdom of Ends' [1996], §4) | |
| A reaction: A nice distinction, which invites us to further subdivide action theory into two branches, with entirely different concerns. |
| 9760 | Self-concern may be a source of pain, or a lack of self-respect, or a failure of responsibility [Korsgaard] |
| Full Idea: For utilitarians, self-concern causes needless pain; for Kantians, it evinces a lack of respect for one's own humanity; for the religious moralist, it is a failure of responsibility for what has been placed in one's special care. | |
| From: Christine M. Korsgaard (Intro to 'Creating the Kingdom of Ends' [1996], §5) | |
| A reaction: Worryingly, given my heathenish views, I find the third one the most congenial. If we don't take responsibility for our own selves (e.g. for having a great talent), then no one (even parents) will take responsibility for anything. |
| 9761 | Personal concern for one's own self widens out into concern for the impersonal [Korsgaard] |
| Full Idea: The personal concern which begins with one's life in a particular body finds its place in ever-widening spheres of agency and enterprise, developing finally into a personal concern for the impersonal. | |
| From: Christine M. Korsgaard (Intro to 'Creating the Kingdom of Ends' [1996], §5) | |
| A reaction: I am very struck by this nice thought, which comes from a very committed Kantian. It seems to me to capture the modern orthodoxy in ethical thinking - that concern for one's self, rather than altruism, is central, but altruism should follow from it. |