14 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. |
| 6451 | Visual sense data are an inner picture show which represents the world [Blackburn] |
| Full Idea: In the case of vision, sense data are a kind of inner picture show which itself only indirectly represents aspects of the external world. | |
| From: Simon Blackburn (Oxford Dictionary of Philosophy [1994], p.347) | |
| A reaction: I'm unsure whether this is correct. Russell says the 'roughness' of the table is the sense datum. If it is even a possibility that there are unsensed sense-data, then they cannot be an aspect of the mind, as Blackburn is suggesting they are. |
| 2866 | A true belief might be based on a generally reliable process that failed on this occasion [Blackburn] |
| Full Idea: Reliabilism is open to the counterexample that a belief may be the result of some generally reliable process (a pressure gauge) which was in fact malfunctioning on this occasion, when we would be reluctant to attribute knowledge to the subject. | |
| From: Simon Blackburn (Oxford Dictionary of Philosophy [1994], p.327) | |
| A reaction: Russell's stopped clock that tells the right time twice a day. A good objection. Coming from a reliable source is very good criterion for good justification, but it needs critical assessment. |
| 16618 | Intellectual and moral states, and even the soul itself, depend on prime matter for their existence [Blasius, by Pasnau] |
| Full Idea: Blasius argued that prime matter is the subject of all our intellectual and moral states. This implies that such states cannot exist apart from the body, which seems to imply further that the soul itself cannot exist apart from the body. | |
| From: report of Blasius of Parma (Les quaestiones de anima (lectures on the soul) [1385], I.8 p.65) by Robert Pasnau - Metaphysical Themes 1274-1671 06.3 | |
| A reaction: It seems that, under pressure, Blasius recanted this view in lectures given eleven years later. |
| 2864 | The main objection to intuitionism in ethics is that intuition is a disguise for prejudice or emotion [Blackburn] |
| Full Idea: Critics say that intuitionism in ethics explains nothing, but may merely function as a disguise for prejudice or passion. | |
| From: Simon Blackburn (Oxford Dictionary of Philosophy [1994], p.198) | |
| A reaction: If someone claims to have an important moral intuition about something, you should carefully assess the person who has the intuition. I would trust some people a lot. |
| 2865 | Critics of prescriptivism observe that it is consistent to accept an ethical verdict but refuse to be bound by it [Blackburn] |
| Full Idea: Critics of prescriptivism have noted the problem that whilst accepting a command seems tantamount to setting oneself to obey it, accepting an ethical verdict is, unfortunately, consistent with refusing to be bound by it. | |
| From: Simon Blackburn (Oxford Dictionary of Philosophy [1994], p.300) | |
| A reaction: We nearly all of us accept that our behaviour should be better than it actually is, so we accept the oughts but fail to act. Actually 'refusing', though, sounds a bit contradictory. |