21 ideas
| 15557 | Verisimilitude has proved hard to analyse, and seems to have several components [Lewis] |
| Full Idea: The analysis of verisimilitude has been much debated. Some plausible analyses have failed disastrously, others conflict with one another. One conclusion is that verisimilitude seems to consist of several distinguishable virtues. | |
| From: David Lewis (Causal Explanation [1986], V n7) | |
| A reaction: Presumably if it is complex, you can approach truth in one respect while receding from it in another. It seems clear enough if you are calculating pi by some iterative process. |
| 13338 | '"It is snowing" is true if and only if it is snowing' is a partial definition of the concept of truth [Tarski] |
| Full Idea: Statements of the form '"it is snowing" is true if and only if it is snowing' and '"the world war will begin in 1963" is true if and only if the world war will being in 1963' can be regarded as partial definitions of the concept of truth. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.404) | |
| A reaction: The key word here is 'partial'. Truth is defined, presumably, when every such translation from the object language has been articulated, which is presumably impossible, given the infinity of concatenated phrases possible in a sentence. |
| 13337 | A language: primitive terms, then definition rules, then sentences, then axioms, and finally inference rules [Tarski] |
| Full Idea: For a language, we must enumerate the primitive terms, and the rules of definition for new terms. Then we must distinguish the sentences, and separate out the axioms from amng them, and finally add rules of inference. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.402) | |
| A reaction: [compressed] This lays down the standard modern procedure for defining a logical language. Once all of this is in place, we then add a semantics and we are in business. Natural deduction tries to do without the axioms. |
| 13335 | Semantics is the concepts of connections of language to reality, such as denotation, definition and truth [Tarski] |
| Full Idea: Semantics is the totality of considerations concerning concepts which express connections between expressions of a language and objects and states of affairs referred to by these expressions. Examples are denotation, satisfaction, definition and truth. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.401) | |
| A reaction: Interestingly, he notes that it 'is not commonly recognised' that truth is part of semantics. Nowadays truth seems to be the central concept in most semantics. |
| 13336 | A language containing its own semantics is inconsistent - but we can use a second language [Tarski] |
| Full Idea: People have not been aware that the language about which we speak need by no means coincide with the language in which we speak. ..But the language which contains its own semantics must inevitably be inconsistent. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.402) | |
| A reaction: It seems that Tarski was driven to propose the metalanguage approach mainly by the Liar Paradox. |
| 13339 | A sentence is satisfied when we can assert the sentence when the variables are assigned [Tarski] |
| Full Idea: Here is a partial definition of the concept of satisfaction: John and Peter satisfy the sentential function 'X and Y are brothers' if and only if John and Peter are brothers. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.405) | |
| A reaction: Satisfaction applies to open sentences and truth to closed sentences (with named objects). He uses the notion of total satisfaction to define truth. The example is a partial definition, not just an illustration. |
| 13340 | Satisfaction is the easiest semantical concept to define, and the others will reduce to it [Tarski] |
| Full Idea: It has been found useful in defining semantical concepts to deal first with the concept of satisfaction; both because the definition of this concept presents relatively few difficulties, and because the other semantical concepts are easily reduced to it. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.406) | |
| A reaction: See Idea 13339 for his explanation of satisfaction. We just say that a open sentence is 'acceptable' or 'assertible' (or even 'true') when particular values are assigned to the variables. Then sentence is then 'satisfied'. |
| 13341 | Using the definition of truth, we can prove theories consistent within sound logics [Tarski] |
| Full Idea: Using the definition of truth we are in a position to carry out the proof of consistency for deductive theories in which only (materially) true sentences are (formally) provable. | |
| From: Alfred Tarski (The Establishment of Scientific Semantics [1936], p.407) | |
| A reaction: This is evidently what Tarski saw as the most important first fruit of his new semantic theory of truth. |
| 15554 | A disposition needs a causal basis, a property in a certain causal role. Could the disposition be the property? [Lewis] |
| Full Idea: I take for granted that a disposition requires a causal basis: one has the disposition iff one has a property that occupies a certain causal role. Shall we then identify the disposition with its basis? That makes the disposition cause its manifestations. | |
| From: David Lewis (Causal Explanation [1986], III) | |
| A reaction: Introduce the concept of a 'power' and I see no problem with his proposal. Fundamental dispositions are powerful, and provide the causal basis for complex dispositions. Something had better be powerful. |
| 15560 | We can explain a chance event, but can never show why some other outcome did not occur [Lewis] |
| Full Idea: I think we are right to explain chance events, yet we are right also to deny that we can ever explain why a chance process yields one outcome rather than another. We cannot explain why one event happened rather than the other. | |
| From: David Lewis (Causal Explanation [1986], VI) | |
| A reaction: This misses out an investigation which slowly reveals that a 'chance' event wasn't so chancey after all. Failure to explain confirms chance, so the judgement of chance shouldn't block attempts to explain. |
| 15559 | Does a good explanation produce understanding? That claim is just empty [Lewis] |
| Full Idea: It is said that a good explanation ought to produce understanding, ...but this just says that a good explanation produces possession of that which it provide, so this desideratum is empty. It adds nothing to our understanding of explanation. | |
| From: David Lewis (Causal Explanation [1986], V) | |
| A reaction: I am not convinced by this dismissal. If you are looking for a test of whether an explanation is good, the announcement that the participants feel they have achieved a good understanding sounds like success. |
| 15556 | Science may well pursue generalised explanation, rather than laws [Lewis] |
| Full Idea: The pursuit of general explanations may be very much more widespread in science than the pursuit of general laws. | |
| From: David Lewis (Causal Explanation [1986], IV) | |
| A reaction: Nice. I increasingly think that the main target of all enquiry is ever-widening generality, with no need to aspire to universality. |
| 15558 | A good explanation is supposed to show that the event had to happen [Lewis] |
| Full Idea: It is said that a good explanation ought to show that the explanandum event had to happen, given the laws and circumstances. | |
| From: David Lewis (Causal Explanation [1986], V) | |
| A reaction: I cautiously go along with this view. Given that there are necessities in nature (a long story), we should aim to reveal them. There is no higher aspiration open to us than successful explanation. Lewis says good explanations can reveal falsehoods. |
| 4809 | Lewis endorses the thesis that all explanation of singular events is causal explanation [Lewis, by Psillos] |
| Full Idea: Lewis endorses the thesis that all explanation of singular events is causal explanation. | |
| From: report of David Lewis (Causal Explanation [1986]) by Stathis Psillos - Causation and Explanation p.237 | |
| A reaction: It is hard to challenge this. The assumption is that only nomological and causal explanations are possible, and the former are unobtainable for singular events. |
| 14321 | To explain an event is to provide some information about its causal history [Lewis] |
| Full Idea: Here is my main thesis: to explain an event is to provide some information about its causal history. | |
| From: David Lewis (Causal Explanation [1986], II) | |
| A reaction: The obvious thought is that you might provide some tiny and barely relevant part of that causal history, such as a bird perched on the Titanic's iceberg. So how do we distinguish the 'important' causal information? |
| 541 | Virtue comes more from habit than character [Critias] |
| Full Idea: More men are good through habit than through character. | |
| From: Critias (fragments/reports [c.440 BCE], B09), quoted by John Stobaeus - Anthology 3.29.41 |
| 15555 | Explaining match lighting in general is like explaining one lighting of a match [Lewis] |
| Full Idea: Explaining why struck matches light in general is not so very different from explaining why some particular struck match lit. ...We may generalize modestly, without laying claim to universality. | |
| From: David Lewis (Causal Explanation [1986], IV) | |
| A reaction: A suggestive remark, since particular causation and general causation seem far apart, but Lewis suggests that the needs of explanation bring them together. Lawlike and unlawlike explanations? |
| 15551 | Ways of carving causes may be natural, but never 'right' [Lewis] |
| Full Idea: There is no one right way - though there may be more or less natural ways - of carving up a causal history. | |
| From: David Lewis (Causal Explanation [1986], I) | |
| A reaction: This invites a distinction between the 'natural' causes and the 'real' causes. Presumably if any causes were 'real', they would have a better claim to be 'right'. Is an earthquake the 'real' (correct?) cause of a tsunami? |
| 15552 | We only pick 'the' cause for the purposes of some particular enquiry. [Lewis] |
| Full Idea: Disagreement about 'the' cause is only disagreement about which part of the causal history is most salient for the purposes of some particular inquiry. | |
| From: David Lewis (Causal Explanation [1986], I) | |
| A reaction: I don't believe this. In the majority of cases I see the cause of an event, without having any interest in any particular enquiry. It is just so obvious that there isn't even a disagreement. Maybe there is only one sensible enquiry. |
| 15553 | Causal dependence is counterfactual dependence between events [Lewis] |
| Full Idea: I take causal dependence to be counterfactual dependence, of a suitably back-tracking sort, between distinct events. | |
| From: David Lewis (Causal Explanation [1986], I) | |
| A reaction: He quotes Hume in support. 'Counterfactual dependence' strikes me as too vague, or merely descriptive, for the job of explanation. 'If...then' is a logical relationship; what is it in nature that justifies the dependency? |
| 542 | Fear of the gods was invented to discourage secret sin [Critias] |
| Full Idea: When the laws forbade men to commit open crimes of violence, and they began to do them in secret, a wise and clever man invented fear of the gods for mortals, to frighten the wicked, even if they sin in secret. | |
| From: Critias (fragments/reports [c.440 BCE], B25), quoted by Sextus Empiricus - Against the Professors (six books) 9.54 |