7 ideas
| 18812 | Split out the logical vocabulary, make an assignment to the rest. It's logical if premises and conclusion match [Tarski, by Rumfitt] |
| Full Idea: Tarski made a division of logical and non-logical vocabulary. He then defined a model as a non-logical assignment satisfying the corresponding sentential function. Then a conclusion follows logically if every model of the premises models the conclusion. | |
| From: report of Alfred Tarski (The Concept of Logical Consequence [1936]) by Ian Rumfitt - The Boundary Stones of Thought 3.2 | |
| A reaction: [compressed] This is Tarski's account of logical consequence, which follows on from his account of truth. 'Logical validity' is then 'true in every model'. Rumfitt doubts whether Tarski has given the meaning of 'logical consequence'. |
| 13344 | X follows from sentences K iff every model of K also models X [Tarski] |
| Full Idea: The sentence X follows logically from the sentences of the class K if and only if every model of the class K is also a model of the sentence X. | |
| From: Alfred Tarski (The Concept of Logical Consequence [1936], p.417) | |
| A reaction: [see Idea 13343 for his account of a 'model'] He is offering to define logical consequence in general, but this definition fits what we now call 'semantic consequence', written |=. This it is standard practice to read |= as 'models'. |
| 13343 | A 'model' is a sequence of objects which satisfies a complete set of sentential functions [Tarski] |
| Full Idea: An arbitrary sequence of objects which satisfies every sentential function of the sentences L' will be called a 'model' or realization of the class L of sentences. There can also be a model of a single sentence is this way. | |
| From: Alfred Tarski (The Concept of Logical Consequence [1936], p.417) | |
| A reaction: [L' is L with the constants replaced by variables] Tarski is the originator of model theory, which is central to modern logic. The word 'realization' is a helpful indicator of what he has in mind. A model begins to look like a possible world. |
| 13345 | Sentences are 'analytical' if every sequence of objects models them [Tarski] |
| Full Idea: A class of sentences can be called 'analytical' if every sequence of objects is a model of it. | |
| From: Alfred Tarski (The Concept of Logical Consequence [1936], p.418) | |
| A reaction: See Idea 13344 and Idea 13343 for the context of this assertion. |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| Full Idea: In singing and playing the lyre, a boy will be likely to reveal not only courage and moderation, but also justice. | |
| From: Damon (fragments/reports [c.460 BCE], B4), quoted by (who?) - where? |
| 23405 | Rituals escape natural chaos, and benefit everyone, by reshaping our motivations [Xunzi (Xun Kuang), by Norden] |
| Full Idea: For Xunzi, everyone is better off with rituals …because they allow us to escape the chaotic state of nature. They do not merely set rules for entitlement, though. They are effective because they reshape human motivation. | |
| From: report of Xunzi (Xun Kuang) (The Xunzi [c.250 BCE]) by Bryan van Norden - Intro to Classical Chinese Philosophy 10.2 | |
| A reaction: Rituals are a basic part of Confucianist thinking, and may be puzzling to outsiders. At there worst rituals are brain-washing, but teaching children good manners is a sort of ritual, meant to channel feelings in a healthy direction |
| 23406 | Rituals don't arise from human nature; they are the deliberate creations of a sage [Xunzi (Xun Kuang)] |
| Full Idea: Rituals and standards of righteousness and proper models and measures are produced from the deliberate efforts of the sage; they are not produced from people's nature. | |
| From: Xunzi (Xun Kuang) (The Xunzi [c.250 BCE], 23), quoted by Bryan van Norden - Intro to Classical Chinese Philosophy 10.III | |
| A reaction: This is not to say that the sage is not in tune with nature. Human nature is often seen as a sprouting seed, which needs careful husbandry to bring out its best. |