21 ideas
| 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. |
| 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. |
| 8090 | Since the language of thought is the same for all, it must be something like logical form [Fodor, by Devlin] |
| Full Idea: Fodor and Jackendorff argue that since the internal language of thought, or conceptual structure, has to be more or less the same for all people, of whatever language, it will surely be something like logical form. | |
| From: report of Jerry A. Fodor (The Language of Thought [1975]) by Keith Devlin - Goodbye Descartes Ch.8 | |
| A reaction: The discovery (by, e.g., Frege and Russell) that there is something called 'logical form', which we can track down and represent in precise and fairly unambiguous symbolism, may be one of the greatest of all human discoveries. Perhaps. |
| 11143 | If concept-learning is hypothesis-testing, that needs innate concepts to get started [Fodor, by Margolis/Laurence] |
| Full Idea: Fodor argues that virtually all lexical concepts are innate, because most models of learning treat concept-learning as hypothesis testing, but that invariably employs the very concept to be learned. | |
| From: report of Jerry A. Fodor (The Language of Thought [1975]) by E Margolis/S Laurence - Concepts 3.3 | |
| A reaction: The obvious response is to reject the theory which gave rise to this difficulty. I take concept formation to be a fairly mechanical and barely conscious response to environment, not a process of fully rational and conscious hypothesising. |
| 23529 | Conduct is not isolated from its effect on the moral code [Hart,HLA] |
| Full Idea: We must not view conduct in isolation from its effect on the moral code. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], II 'Moderate') | |
| A reaction: The moral code may be excessively conservative, but there is no denying this point. Extreme individualistic libertarians must recognise that 'no man is an island'. |
| 23530 | The great danger of democracy is that the oppression of the minority becomes unobjectionable [Hart,HLA] |
| Full Idea: For Mill and De Tocqueville the greatest of the dangers was not that in fact the majority might use their power to oppress a minority, but that, with the spread of democratic ideas, it might come to be thought unobjectionable that they should do so. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], III 'Populism') | |
| A reaction: This was vivid in the 2016 Brexit referendum, which was 52-48 in favour of leaving. There were lots voices saying 'you lost, get over it'. It should be a basic (if neglected) principle that the winners of elections now represent the whole population. |
| 23522 | In an organised society all actions have some effect on other people [Hart,HLA] |
| Full Idea: In an organised society it is impossible to identify classes of actions which harm no one, or no one but the individual who does them. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], I 'Enforcement') | |
| A reaction: This is attributed to 'some critics' of Mill. I agree with this. The idea that actions performed behind close doors never come to influence social life is an illusion, held by people whose quest for freedom is selfish. |
| 23528 | The value of liberty allows freedom of action, even if that distresses other people [Hart,HLA] |
| Full Idea: Recognition of individual liberty as a value involves, as a minimum, acceptance of the principle that the individual may do what he wants, even if others are distressed when the learn what it is that he does. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], II 'Private') | |
| A reaction: He notes that there could be other reasons to block the freedom, such as harm done. This idea seems to identify a key component of liberalism - that we must all tolerate actions which we dislike. |
| 23523 | The principle of legality requires crimes to be precisely defined in advance of any action [Hart,HLA] |
| Full Idea: The principle of legality requires criminal offences to be as precisely defined as possible, so that it can be known with reasonable certainty beforehand what acts are criminal and what are not. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], I 'Conspiracy') | |
| A reaction: Hart is discussing a breach of this, where moral judgements are used to condemn something which was not obviously illegal. Families and schools don't have such precise rules, but it seems needed in a vast and pluralistic society. |
| 23524 | Some private moral issues are no concern of the law [Hart,HLA] |
| Full Idea: An official report [of 1957] on homosexuality declared that 'there must remain a realm of private morality and immorality which is, in brief and crude terms, not the law's business'. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], I 'Conspiracy') | |
| A reaction: We might wonder whether these issues are actually moral, if the law is not interested in them. Are they just a matter of taste? The law doesn't enforce a preference for Mozart over Salieri. |
| 23521 | Do morals influence law? Is morality an aspect of law? Can law be morally criticised? [Hart,HLA] |
| Full Idea: Four questions: 1) Has the development of law been influenced by morals? 2) Must reference to morality enter into an adequate definition of law or legal system? 3) Is law open to moral criticism? 4) Does immorality justify legal punishment? | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], I 'Enforcement') | |
| A reaction: [compressed] Three nice questions, which are his agenda for the book. It is obvious that immoral laws can be created, and that laws can be criticised for being too concerned with morality, so there is no clear general answer to these dilemmas. |
| 23525 | Is the enforcement of morality morally justifiable? [Hart,HLA] |
| Full Idea: The question about morality and the law is also a question of morality - of whether the enforcement of morality is morally justified. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], I 'Positive') | |
| A reaction: This is a very nice meta-moral question. What moral standards are used to justify the enforcement of moral standards? Presumably there should be no contradiction between the levels, to brutally enforce softness, or softly recommend brutality? |
| 23526 | Modern law still suppresses practices seen as immoral, and yet harmless [Hart,HLA] |
| Full Idea: English and American law still [in1963] contain rules which suppress practices condemned as immoral by positive morality though they involve nothing that would be ordinarily thought of as harm to other persons. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], II 'Use') | |
| A reaction: He says most of the examples of this concern sexual practices. In the UK we have moved away from such laws, but many states of the USA still maintain them (or are reintroducing them, in 2023). |
| 23527 | Moral wickedness of an offence is always relevant to the degree of punishment [Hart,HLA] |
| Full Idea: Leslie Stephen argued that when the question is how severely an offender should be punished, an estimate of the degree of moral wickedness involved in the crime is always relevant. | |
| From: H.L.A. Hart (Law,Liberty and Morality [1963], II 'Moral') | |
| A reaction: [Stephen 'Liberty, Equality, Fraternity' 1873] The degree of responsibility (after excuses etc.) is obviously also highly relevant. If vicious murder is punished more harshly, that seems to be an assessment of the character of the murderer. |