15 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. |
| 17644 | Metaphysical realism is committed to there being one ultimate true theory [Putnam] |
| Full Idea: What makes the metaphysical realist a 'metaphysical' realist is his belief that there is somewhere 'one true theory' (two theories which are true and complete descriptions of the world would be mere notational variants of each other). | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Causation') | |
| A reaction: This is wrong!!!!! Commitment to one reality doesn't imply that only one comprehensive theory is possible. Theory-making (at least in any human language, or in mathematics) is an inherently limited activity. |
| 17648 | It is an illusion to think there could be one good scientific theory of reality [Putnam] |
| Full Idea: The idea of a coherent theory of the noumena; consistent, systematic, and arrived at by 'the scientific method' seems to me to be chimerical. | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Failure') | |
| A reaction: I sort of agree with this, but it definitely doesn't make me an anti-realist. |
| 17643 | Shape is essential relative to 'statue', but not essential relative to 'clay' [Putnam] |
| Full Idea: Relative to the description 'that statue', a certain shape is an essential property of the object; relative to the description 'that piece of clay', the shape not an essential property (but being clay is). | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Intro') | |
| A reaction: Relative to the description 'that loathsome object', is the statue essentially loathsome? Asserting the essence of an object is a response to the object, not a response to a description of it. This is not the solution to the statue problem. |
| 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. |
| 6672 | Moore's Paradox: you can't assert 'I believe that p but p is false', but can assert 'You believe p but p is false' [Moore,GE, by Lowe] |
| Full Idea: Moore's Paradox says it makes no sense to assert 'I believe that p, but p is false', even though it makes perfectly good sense to assert 'I used to believe p, but p is false' or 'You believe p, but p is false'. | |
| From: report of G.E. Moore (works [1905]) by E.J. Lowe - Introduction to the Philosophy of Mind Ch.10 | |
| A reaction: I'm not sure if this really deserves the label of 'paradox'. I take it as drawing attention to the obvious fact that belief is commitment to truth. I think my assessment that p is true is correct, but your assessment is wrong. ('True' is not redundant!) |
| 17642 | The old view that sense data are independent of mind is quite dotty [Putnam] |
| Full Idea: Moore and Russell held the strange view that 'sensibilia' (sense data) are mind-independent entities: a view so dotty, on the face of it, that few analytic philosophers like to be reminded that this is how analytic philosophy started. | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Intro') | |
| A reaction: I suspect the view was influenced by the anti-psychologism of Frege, and his idea that all the other concepts are mind-independent, living by their own rules in a 'third realm'. Personally I think analytic philosophy needs more psychology, not less. |
| 17645 | An alien might think oxygen was the main cause of a forest fire [Putnam] |
| Full Idea: Imagine a Venusian lands on Earth and observes a forest fire, and says 'I know what caused that - the atmosphere is saturated with oxygen!'. Thus one man's 'background condition' can easily be another man's 'cause'. | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Causation') | |
| A reaction: You can't sweep 'the' cause of a fire away so easily. There is always oxygen on Earth, but only occasional forest fires. The oxygen doesn't 'trigger' the fire (i.e. it isn't the proximate cause). |