14 ideas
| 23877 | Most people won't question an idea's truth if they depend on it [Weil] |
| Full Idea: The majority of human beings do not question the truth of an idea without which they would literally be unable to live. | |
| From: Simone Weil (Is There a Marxist Doctrine? [1943], p.163) | |
| A reaction: I assume that this inability grows stronger with age, as the dependence on the idea runs deeper. Hence for most people the beliefs which sustain them have a higher value than truth. Obviously we should all make love of truth our guiding idea! |
| 18739 | Three stages of philosophical logic: syntactic (1905-55), possible worlds (1963-85), widening (1990-) [Horsten/Pettigrew] |
| Full Idea: Three periods can be distinguished in philosophical logic: the syntactic stage, from Russell's definite descriptions to the 1950s, the dominance of possible world semantics from the 50s to 80s, and a current widening of the subject. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 1) | |
| A reaction: [compressed] I've read elsewhere that the arrival of Tarski's account of truth in 1933, taking things beyond the syntactic, was also a landmark. |
| 18741 | Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew] |
| Full Idea: Logical formalization forces the investigator to make the central philosophical concepts precise. It can also show how some philosophical concepts and objects can be defined in terms of others. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 2) | |
| A reaction: This is the main rationale of the highly formal and mathematical approach to such things. The downside is when you impose 'precision' on language that was never intended to be precise. |
| 18744 | Models are sets with functions and relations, and truth built up from the components [Horsten/Pettigrew] |
| Full Idea: A (logical) model is a set with functions and relations defined on it that specify the denotation of the non-logical vocabulary. A series of recursive clauses explicate how truth values of complex sentences are compositionally determined from the parts. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 3) | |
| A reaction: See the ideas on 'Functions in logic' and 'Relations in logic' (in the alphabetical list) to expand this important idea. |
| 18740 | If 'exist' doesn't express a property, we can hardly ask for its essence [Horsten/Pettigrew] |
| Full Idea: If there is indeed no property of existence that is expressed by the word 'exist', then it makes no sense to ask for its essence. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 2) | |
| A reaction: As far as I can tell, this was exactly Aristotle's conclusion, so he skirted round the question of 'being qua being', and focused on the nature of objects instead. Grand continental talk of 'Being' doesn't sound very interesting. |
| 5451 | Popper felt that ancient essentialism was a bar to progress [Popper, by Mautner] |
| Full Idea: Karl Popper vehemently rejected the essentialism which underpins Plato and Aristotle, taking it to be a major obstacle to political, moral and scientific progress. | |
| From: report of Karl Popper (Open Society and Its Enemies:Hegel and Marx [1945]) by Thomas Mautner - Penguin Dictionary of Philosophy p.179 | |
| A reaction: This makes Popper sound like an existentialist, which seems unlikely. Modern essentialism would say the opposite about science - that hunting for external imposed laws is a red herring, and we should try to understand essences. |
| 18745 | A Tarskian model can be seen as a possible state of affairs [Horsten/Pettigrew] |
| Full Idea: A Tarskian model can in a sense be seen as a model of a possible state of affairs. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 3) | |
| A reaction: I include this remark to show how possible worlds semantics built on the arrival of model theory. |
| 18747 | The 'spheres model' was added to possible worlds, to cope with counterfactuals [Horsten/Pettigrew] |
| Full Idea: The notion of a possible worlds model was extended (resulting in the concept of a 'spheres model') in order to obtain a satisfactory logical treatment of counterfactual conditional sentences. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 4) | |
| A reaction: Thus we add 'centred' worlds, and an 'actual' world, to the loose original model. It is important to remember when we discuss 'close' worlds that we are then committed to these presuppositions. |
| 18748 | Epistemic logic introduced impossible worlds [Horsten/Pettigrew] |
| Full Idea: The idea of 'impossible worlds' was introduced into epistemic logic. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 4) | |
| A reaction: Nathan Salmon seems interested in their role in metaphysics (presumably in relation to Meinongian impossible objects, like circular squares, which must necessarily be circular). |
| 18746 | Possible worlds models contain sets of possible worlds; this is a large metaphysical commitment [Horsten/Pettigrew] |
| Full Idea: Each possible worlds model contains a set of possible worlds. For this reason, possible worlds semantics is often charged with smuggling in heavy metaphysical commitments. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 3) | |
| A reaction: To a beginner it looks very odd that you should try to explain possibility by constructing a model of it in terms of 'possible' worlds. |
| 18750 | Using possible worlds for knowledge and morality may be a step too far [Horsten/Pettigrew] |
| Full Idea: When the possible worlds semantics were further extended to model notions of knowledge and of moral obligation, the application was beginning to look distinctly forced and artificial. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 5) | |
| A reaction: They accept lots of successes in modelling necessity and time. |
| 23878 | Weakness of will is the inadequacy of the original impetus to carry through the action [Weil] |
| Full Idea: It is naïve to be astonished when we do not stick to firm resolutions. Something stimulated the resolution, but that something was not powerful enough to bring us to the point of carrying it out. Making the resolution may even have exhausted the stimulus. | |
| From: Simone Weil (Is There a Marxist Doctrine? [1943], p.169) | |
| A reaction: Socrates says it is a change of belief. Aristotle says it is a desire overcoming a belief. Weil gives a third way: that it is a fading in the strength of the original belief/desire impetus. |
| 23879 | In a violent moral disagreement, it can't be that both sides are just following social morality [Weil] |
| Full Idea: If two men are in violent disagreement about good and evil, it is hard to believe that both of them are blindly subject to the opinion of the society around them. | |
| From: Simone Weil (Is There a Marxist Doctrine? [1943], p.171) | |
| A reaction: What a beautifully simple observation. Simone would have become a major figure if she had lived longer. No philosopher has ever written better prose. |
| 23880 | When war was a profession, customary morality justified any act of war [Weil] |
| Full Idea: At the time when war was a profession, fighting men had a morality whereby any act of war, in accordance with the customs of war, and contributing to victory, was legitimate and right. | |
| From: Simone Weil (Is There a Marxist Doctrine? [1943], p.173) | |
| A reaction: Note the caveat about 'customs', which were largely moral. See the discussion of killing the non-combatant prisoners in Shakespeare's 'Henry V'. |