23 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. |
| 19542 | It is nonsense that understanding does not involve knowledge; to understand, you must know [Dougherty/Rysiew] |
| Full Idea: The proposition that understanding does not involve knowledge is widespread (for example, in discussions of what philosophy aims at), but hardly withstands scrutiny. If you do not know how a jet engine works, you do not understand how it works. | |
| From: Dougherty,T/Rysiew,P (Experience First (and reply) [2014], p.24) | |
| A reaction: This seems a bit disingenuous. As in 'Theaetetus', knowing the million parts of a jet engine is not to understand it. More strongly - how could knowledge of an infinity of separate propositional truths amount to understanding on their own? |
| 19543 | To grasp understanding, we should be more explicit about what needs to be known [Dougherty/Rysiew] |
| Full Idea: An essential prerequisite for useful discussion of the relation between knowledge and understanding is systematic explicitness about what is to be known or understood. | |
| From: Dougherty,T/Rysiew,P (Experience First (and reply) [2014], p.25) | |
| A reaction: This is better. I say what needs to be known for understanding is the essence of the item under discussion (my PhD thesis!). Obviously understanding needs some knowledge, but I take it that epistemology should be understanding-first. That is the main aim. |
| 20189 | Belief is a feeling, independent of the will, which arises from uncontrolled and unknown causes [Hume] |
| Full Idea: Belief consists merely in a certain feeling or sentiment; in something, that depends not on the will, but must arise from certain determinate causes and principles, of which we are not master. | |
| From: David Hume (Treatise of Human Nature, + Appendix [1740], Appen p.2) | |
| A reaction: This is the opposite of Descartes' 'doxastic voluntarism' (i.e. we choose what to believe). If you want to become a Christian, steep yourself in religious literature, and the company of religious people. It will probably work. |
| 19541 | Rather than knowledge, our epistemic aim may be mere true belief, or else understanding and wisdom [Dougherty/Rysiew] |
| Full Idea: If we say our cognitive aim is to get knowledge, the opposing views are the naturalistic view that what matters is just true belief (or just 'getting by'), or that there are rival epistemic goods such as understanding and wisdom. | |
| From: Dougherty,T/Rysiew,P (Experience First (and reply) [2014], p.17) | |
| A reaction: [compressed summary] I'm a fan of understanding. The accumulation of propositional knowledge would relish knowing the mass of every grain of sand on a beach. If you say the propositions should be 'important', other values are invoked. |
| 21309 | A proposition cannot be intelligible or consistent, if the perceptions are not so [Hume] |
| Full Idea: No proposition can be intelligible or consistent with regard to objects, which is not so with regard to perceptions. | |
| From: David Hume (Treatise of Human Nature, + Appendix [1740], Appendix) | |
| A reaction: An interesting variant on expressions of the empiricist principle. Presumably one can say intelligible things about Escher drawings. |
| 15755 | Hume needs a notion which includes degrees of resemblance [Shoemaker on Hume] |
| Full Idea: Hume needs a notion of resemblance where some things resemble a given thing more than other things do, and some may resemble exactly, and some hardly at all. | |
| From: comment on David Hume (Treatise of Human Nature, + Appendix [1740]) by Sydney Shoemaker - Causality and Properties §02 | |
| A reaction: An astute and simple point. Once you admit degrees of resemblance, of course, then resemblance probably ceases to be a primitive concept in your system, and Hume would be well stuck. |
| 5323 | Experiences are logically separate, but factually linked by simultaneity or a feeling of continuousness [Ayer on Hume] |
| Full Idea: Our experiences are logically independent, but they may be factually connected. What unites them is that either they are experienced together, or (if at separate times) they are separated by a stream of experience which is felt to be continuous. | |
| From: comment on David Hume (Treatise of Human Nature, + Appendix [1740], Bk 3 App.) by A.J. Ayer - The Central Questions of Philosophy §VI.A | |
| A reaction: A strict empiricist cannot deny that the feeling of continuity could be false, though that invites the Cartesian question of what exactly is experiencing the delusion. Hume denies that we experience any link between simultaneous experiences. |
| 21311 | Are self and substance the same? Then how can self remain if substance changes? [Hume] |
| Full Idea: Is the self the same with substance? If it be, how can that question have place concerning the subsistence of self, under a change of substance? If they be distinct, what is the difference between them? | |
| From: David Hume (Treatise of Human Nature, + Appendix [1740], Appendix) | |
| A reaction: Locke seems to think there is a characterless substance which supports momories, and the latter constitute the self. So if my substance acquires Nestor's memories, I become Nestor. Hume, the stricter empiricist, cares nothing for characterless things. |
| 21312 | Perceptions are distinct, so no connection between them can ever be discovered [Hume] |
| Full Idea: If perceptions are distinct existences, they form a whole only by being connected together. But no connexions among distinct existences are ever discoverable. We only feel a connexion ...to pass from one object to another. | |
| From: David Hume (Treatise of Human Nature, + Appendix [1740], Appendix) | |
| A reaction: This first part of this is a problem for any 'bundle' theory of objects or self. This is why Hume abandons all hope for his theory of personal identity based on association. You infer the associations, but don't perceive them. |
| 21308 | We have no impression of the self, and we therefore have no idea of it [Hume] |
| Full Idea: Every idea is derived from preceding impressions; and we have no impression of self or substance, as something simple and individual. We have, therefore, no idea of them in that sense. | |
| From: David Hume (Treatise of Human Nature, + Appendix [1740], Appendix) | |
| A reaction: This spells out with beautiful simplicity how his empiricist assumptions lead him to this sceptical view. No logical positivist could reject this thought. Personally I favour empiricism with added inference to the best explanation. |
| 21310 | Does an oyster with one perception have a self? Would lots of perceptions change that? [Hume] |
| Full Idea: Suppose an oyster to have only one perception, as of thirst or hunger. Do you consider any thing but merely that perception? Have you any notion of self or substance? If not, the addition of other perceptions can never give you that notion. | |
| From: David Hume (Treatise of Human Nature, + Appendix [1740], Appendix) | |
| A reaction: A splendid addition to his earlier sceptical thinking. We could form a different conclusion. Suppose I do have a self. If my multitudinous perceptions were reduced to a single perception of agonising pain, would that remove the self? |
| 23115 | We have no natural love of mankind, other than through various relationships [Hume] |
| Full Idea: It may be affirm'd, that there is no such passion in human minds, as the love of mankind, merely as such, independent of personal qualities, of services, or of relation to ourself. | |
| From: David Hume (Treatise of Human Nature, + Appendix [1740], p.481), quoted by John Kekes - Against Liberalism 9.4 | |
| A reaction: Hume says this is for the best. I can't imagine spontaneous love of human beings we have never met. It takes the teachings of some sort of doctrine - religious or political - to produce such an attitude. I see it as a distortion of love. A hijacking. |
| 16946 | Causation is just invariance, as long as it is described in general terms [Quine on Hume] |
| Full Idea: Hume explained cause as invariable succession, and this makes sense as long as the cause and effect are referred to by general terms. … This account leaves singular causal statements unexplained. | |
| From: comment on David Hume (Treatise of Human Nature, + Appendix [1740]) by Willard Quine - Natural Kinds p.131 | |
| A reaction: A nice 20th century linguistic point made against a good 18th century theory. |
| 15250 | If impressions, memories and ideas only differ in vivacity, nothing says it is memory, or repetition [Whitehead on Hume] |
| Full Idea: Hume confuses 'repetition of impressions' with 'impression of repetitions of impressions'. ...In order of 'force and vivacity' we have: impressions, memories, ideas. This omits the vital fact that memory is memory; the notion of repetition is lost. | |
| From: comment on David Hume (Treatise of Human Nature, + Appendix [1740]) by Alfred North Whitehead - Process and Reality V.II | |
| A reaction: [compressed; Harré and Madden spotted this idea] This seems to pinpoint rather nicely the hopeless thinness of Hume's account. He is so desperate to get it down to minimal empirical experience that his explanations are too thin. One big idea.... |