13 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. |
8875 | Sense experiences must have conceptual content, since they are possible reasons for judgements [Brewer,B] |
Full Idea: Given that sense experiential states do provide reasons for empirical beliefs, they must have conceptual content, ...where a mental state with conceptual content is one where the content is of a possible judgement by the subject. | |
From: Bill Brewer (Perceptual experience has conceptual content [2005], I) | |
A reaction: This is, I believe, wrong. Even complex observations, like a pool of blood, only become reasons when they have been interpreted. Otherwise they are just the raw ingredients of evidence. How could an uninterpreted red patch be a 'reason'? |
14802 | Physical and psychical laws of mind are either independent, or derived in one or other direction [Peirce] |
Full Idea: The question about minds is whether 1) physical and psychical laws are independent (monism, my neutralism), 2) the psychical laws derived and physical laws primordial (materialism), 3) physical law is derived, psychical law primordial (idealism). | |
From: Charles Sanders Peirce (The Architecture of Theories [1891], p.321) | |
A reaction: I think you are already in trouble when you start proposing that there are two quite distinct sets of laws, and then worry about how they are related. Assume unity, and only separate them when the science forces you to (which it won't). |
14800 | The world is full of variety, but laws seem to produce uniformity [Peirce] |
Full Idea: Exact law obviously never can produce heterogeneity out of homogeneity; and arbitrary heterogeneity is the feature of the universe the most manifest and characteristic. | |
From: Charles Sanders Peirce (The Architecture of Theories [1891], p.319) | |
A reaction: This is the view of laws of nature now associated with Nancy Cartwright, but presumably you can explain the apparent chaos in terms of the intersection of vast numbers of 'laws'. Or, better, there aren't any laws. |
14801 | Darwinian evolution is chance, with the destruction of bad results [Peirce] |
Full Idea: Darwinian evolution is evolution by the operation of chance, and the destruction of bad results. | |
From: Charles Sanders Peirce (The Architecture of Theories [1891], p.320) | |
A reaction: The 'destruction of bad results' is a much better slogan for Darwin that Spencer's 'survival of the fittest'. It is, of course, a rather unattractive God who makes progress by endlessly destroying huge quantities of failed (but living) experiments. |