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. |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom. | |
| From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88) | |
| A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate'). |
| 20579 | Modern totalitarianism results from lack of social ties or shared goals [Arendt, by Oksala] |
| Full Idea: Arendt claims that modern totalitarianism's primary condition is an atomised mass society: isolated individuals who have no strong ties to communities and who are indifferent to shared political goals. | |
| From: report of Hannah Arendt (The Origins of Totalitarianism [1968]) by Johanna Oksala - Political Philosophy: all that matters Ch.9 | |
| A reaction: I think the lack of ties simply describes large modern cities. Not sure about the lack of shared goals. Hitler and Stalin rode on the back of apparent shared goals. Working classes strike me as sharing more goals than middle classes. |
| 20580 | The ideal subject for dictators is not a fanatic, but someone who can't distinguish true from false [Arendt, by Oksala] |
| Full Idea: The ideal subject of totalitarianism is not the convinced Nazi or the convinced communist, but anyone who has lost the ability to make distinctions between fact and fiction and between true and false. | |
| From: report of Hannah Arendt (The Origins of Totalitarianism [1968]) by Johanna Oksala - Political Philosophy: all that matters Ch.9 | |
| A reaction: We are currently living with an apparent attempt by Donald Trump to become a totalitarian President of the U.S.A., by constantly disseminating lies, and labelling all of his critics as 'fake news'. |