17 ideas
| 13010 | In order to select the logic justified by experience, we would need to use a lot of logic [Boghossian on Quine] |
| Full Idea: Quine ends up with the logic that is maximally justified by experience, ...but a large number of the core principles of logic will have to be used to select the logic that is maximally justified by experience. | |
| From: comment on Willard Quine (Carnap and Logical Truth [1954]) by Paul Boghossian - Knowledge of Logic p.233 | |
| A reaction: In order to grasp some core principles of logic, you will probably need a certain amount of experience. I take logic to be an abstracted feature of reality (unless it is extended by pure fictions). Some basic logic may be hard wired in us. |
| 9002 | Elementary logic requires truth-functions, quantifiers (and variables), identity, and also sets of variables [Quine] |
| Full Idea: Elementary logic, as commonly systematized nowadays, comprises truth-function theory (involving 'or', 'and', 'not' etc.), quantifiers (and their variables), and identity theory ('='). In addition, set theory requires classes among values of variables. | |
| From: Willard Quine (Carnap and Logical Truth [1954], II) | |
| A reaction: Quine is famous for trying to squeeze properties out of the picture, which would then block higher-order logics (which quantify over properties). Quine's list gives a nice programme for a student of the philosophy of logic to understand. |
| 13681 | Logical consequence is marked by being preserved under all nonlogical substitutions [Quine, by Sider] |
| Full Idea: Quine's view of logical consequence is that it is when there is no way of uniformly substituting nonlogical expressions in the premises and consequences so that the premises all remain true but the consequence now becomes false. | |
| From: report of Willard Quine (Carnap and Logical Truth [1954], p.103) by Theodore Sider - Logic for Philosophy 1.5 | |
| A reaction: One might just say that the consequence holds if you insert consistent variables for the nonlogical terms, which looks like Aristotle's view of the matter. |
| 13829 | If logical truths essentially depend on logical constants, we had better define the latter [Hacking on Quine] |
| Full Idea: Quine said a logical truth is a truth in which only logical constants occur essentially, ...but then a fruitful definition of 'logical constant' is called for. | |
| From: comment on Willard Quine (Carnap and Logical Truth [1954]) by Ian Hacking - What is Logic? §02 |
| 9003 | Set theory was struggling with higher infinities, when new paradoxes made it baffling [Quine] |
| Full Idea: Unlike elementary logic, the truths of set theory are not obvious. Set theory was straining at the leash of intuition ever since Cantor discovered higher infinites; and with the added impetus of the paradoxes of set theory the leash snapped. | |
| From: Willard Quine (Carnap and Logical Truth [1954], II) | |
| A reaction: This problem seems to have forced Quine into platonism about sets, because he felt they were essential for mathematics and science, but couldn't be constructed with precision. So they must be real, but we don't quite understand them. |
| 9004 | If set theory is not actually a branch of logic, then Frege's derivation of arithmetic would not be from logic [Quine] |
| Full Idea: We might say that set theory is not really logic, but a branch of mathematics. This would deprive 'includes' of the status of a logical word. Frege's derivation of arithmetic would then cease to count as a derivation from logic: for he used set theory. | |
| From: Willard Quine (Carnap and Logical Truth [1954], II) | |
| A reaction: Quine has been making the point that higher infinities and the paradoxes undermine the status of set theory as logic, but he decides to continue thinking of set theory as logic. Critics of logicism frequently ask whether the reduction is to logic. |
| 15789 | Lewis's distinction of 'existing' from 'being actual' is Meinong's between 'existing' and 'subsisting' [Lycan on Lewis] |
| Full Idea: I suggest that Lewis's view in fact is just Meinong's view. ...Meinong distinguishes between 'existing' and merely 'subsisting', Lewis between 'being actual' and merely 'existing'. | |
| From: comment on David Lewis (Possible Worlds [1973]) by William Lycan - The Trouble with Possible Worlds 06 | |
| A reaction: Lewis attempts to make actuality purely 'indexical' in character, like distinguishing the world 'here' from the world 'elsewhere', but Lycan seems right that he is committed to more than that. |
| 9006 | Commitment to universals is as arbitrary or pragmatic as the adoption of a new system of bookkeeping [Quine] |
| Full Idea: One's hypothesis as to there being universals is at bottom just as arbitrary or pragmatic a matter as one's adoption of a new brand of set theory or even a new system of bookkeeping. | |
| From: Willard Quine (Carnap and Logical Truth [1954], x) | |
| A reaction: This spells out clearly the strongly pragmatist vein in Quine's thinking. |
| 9001 | Frege moved Kant's question about a priori synthetic to 'how is logical certainty possible?' [Quine] |
| Full Idea: When Kant's arithmetical examples of a priori synthetic judgements were sweepingly disqualified by Frege's reduction of arithmetic to logic, attention moved to the less tendentious and logically prior question 'How is logical certainty possible?' | |
| From: Willard Quine (Carnap and Logical Truth [1954], I) | |
| A reaction: A nice summary of the story so far, from someone who should know. This still leaves the question open of whether any synthetic truths can be derived from the logical certainties which are available. |
| 15790 | Lewis can't know possible worlds without first knowing what is possible or impossible [Lycan on Lewis] |
| Full Idea: Lewis's knowledge of what possible worlds there are and of other general truths about worlds is posterior, not prior, to his knowledge of what things are possible and what things are impossible. | |
| From: comment on David Lewis (Possible Worlds [1973]) by William Lycan - The Trouble with Possible Worlds 07 | |
| A reaction: This elementary objection seems to me to destroy any attempt to explain modality in terms of possible worlds. It is a semantics for modal statements, but that doesn't make it an ontology. To assess possibilities, study actuality. |
| 15791 | What are the ontological grounds for grouping possibilia into worlds? [Lycan on Lewis] |
| Full Idea: Lewis must seek some ontological ground for the grouping of possibilia into disjoint worlds. | |
| From: comment on David Lewis (Possible Worlds [1973]) by William Lycan - The Trouble with Possible Worlds 07 | |
| A reaction: I do love people like Lycan who ask the simple commonsense questions about these highly sophisticated systems that students of philosophy are required to study. If a proposition is a 'set of worlds', understanding a proposition is beyond me. |
| 9005 | Examination of convention in the a priori begins to blur the distinction with empirical knowledge [Quine] |
| Full Idea: In trying to make sense of the role of convention in a priori knowledge, the very distinction between a priori and empirical begins to waver and dissolve. | |
| From: Willard Quine (Carnap and Logical Truth [1954], VI) | |
| A reaction: This is the next stage in the argument after Wittgenstein presents the apriori as nothing more than what arises from truth tables. The rationalists react by taking us back to the original 'natural light of reason' view. Then we go round again... |
| 12163 | Literary meaning emerges in comparisons, and tradition shows which comparisons are relevant [Scruton] |
| Full Idea: We must discover the meanings that emerge when works of literature are experience in relation to each other. ...The importance of tradition is that it denotes - ideally, at least - the class of relevant comparisons. | |
| From: Roger Scruton (Public Text and Common Reader [1982], p.27) | |
| A reaction: This is a nice attempt to explain why we all agree that a thorough education in an art is an essential prerequisite for good taste. Some people (e.g. among the young) seem to have natural good taste. How does that happen? |
| 12162 | In literature, word replacement changes literary meaning [Scruton] |
| Full Idea: In literary contexts semantically equivalent words cannot replace each other without loss of literary meaning. | |
| From: Roger Scruton (Public Text and Common Reader [1982], p.25) | |
| A reaction: The notion of 'literary meaning' is not a standard one, and is questionable whether 'meaning' is the right word, given that a shift in word in a poem is as much to do with sound as with connotations. |
| 12159 | Without intentions we can't perceive sculpture, but that is not the whole story [Scruton] |
| Full Idea: A person for whom it made no difference whether a sculpture was carved by wind and rain or by human hand would be unable to interpret or perceive sculptures - even though the interpretation of sculpture is not the reading of an intention. | |
| From: Roger Scruton (Public Text and Common Reader [1982], p.15) | |
| A reaction: Scruton compares it to the role of intention in language, where there is objective meaning, even though intention is basic to speech. |
| 12160 | In aesthetic interest, even what is true is treated as though it were not [Scruton] |
| Full Idea: In aesthetic interest, even what is true is treated as though it were not. | |
| From: Roger Scruton (Public Text and Common Reader [1982], p.18) | |
| A reaction: A nice aphorism. I always feel uncomfortable reading novels about real people, although the historical Macbeth doesn't bother me much. Novels are too close to reality. Macbeth didn't speak blank verse. |
| 12161 | We can be objective about conventions, but love of art is needed to understand its traditions [Scruton] |
| Full Idea: An historian can elucidate convention while having no feeling for the art that exploits it; whereas an understanding of tradition is reserved for those with the critical insight which comes from the love of art, both past and present. | |
| From: Roger Scruton (Public Text and Common Reader [1982], p.24) | |
| A reaction: This aesthetic observation is obviously close to Scruton's well-known conservatism in politics. I am doubtful whether the notion of 'tradition' can stand up to close examination, though we all know roughly what he means. |