45 ideas
| 19066 | Philosophy aims to understand the world, through ordinary experience and science [Dummett] |
| Full Idea: Philosophy is an attempt to understand the world, as it is revealed to us both in our ordinary experience and by the discoveries and theories of science. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.311) | |
| A reaction: I don't see a sharp division between 'ordinary' and 'scientific'. I really like this idea, first because it makes 'understanding' central, and second because it wants both revelations. In discussing matter and time, there is too much emphasis on science. |
| 19067 | A successful proof requires recognition of truth at every step [Dummett] |
| Full Idea: For a demonstration to be cogent it is necessary that the passage from step to step involve a recognition of truth at each line. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.313) | |
| A reaction: Dummett cited Quine (esp. 1970) as having an almost entirely syntactic view of logic. Rumfitt points out that logic can move validly from one falsehood to another. Even a 'proof' might detour into falsehood, but it would not be a 'canonical' proof! |
| 8187 | Frege was strongly in favour of taking truth to attach to propositions [Frege, by Dummett] |
| Full Idea: Frege was strongly in favour of taking truth to attach to propositions, which he called 'thoughts' and regarded as being expressed by sentences. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Michael Dummett - Truth and the Past 1 | |
| A reaction: Sometimes it is necessary to know the time, the place, and the speaker before one can evaluate the truth of a proposition. Not just indexical words, but the indexical aspect of, say, "the team played badly". |
| 19060 | Truth-tables are dubious in some cases, and may be a bad way to explain connective meaning [Dummett] |
| Full Idea: It is arguable whether two-valued truth tables give correct meanings for certain sentential operators, and even whether they constitute legitimate explanations of any possible sentential operators. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: See 'Many-valued logic' for examples of non-binary truth tables. Presumably logicians should aspire to make their semantics precise, as well as their syntax. |
| 11066 | Deduction is justified by the semantics of its metalanguage [Dummett, by Hanna] |
| Full Idea: For Dummett the semantics of the metalanguage is the external and objective source of the justification of deduction. | |
| From: report of Michael Dummett (The Justification of Deduction [1973]) by Robert Hanna - Rationality and Logic 3.4 | |
| A reaction: This is offered as an answer to the Lewis Carroll problem that justifying deduction seems to need deduction, thus leading to a regress. [There is a reply to Dummett by Susan Haack] |
| 19058 | Syntactic consequence is positive, for validity; semantic version is negative, with counterexamples [Dummett] |
| Full Idea: A plausible account is that the syntactic notion of consequence is for positive results, that some form of argument is valid; the semantic notion is required for negative results, that some argument is invalid, because a counterexample can be found. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.292) | |
| A reaction: This rings true for the two strategies of demonstration, the first by following the rules in steps, the second by using your imagination (or a tableau) to think up problems. |
| 18772 | We can treat designation by a few words as a proper name [Frege] |
| Full Idea: The designation of a single object can also consist of several words or other signs. For brevity, let every such designation be called a proper name. | |
| From: Gottlob Frege (On Sense and Reference [1892]), quoted by Bernard Linsky - Quantification and Descriptions 1 | |
| A reaction: Frege regards names and descriptions as in the same class. Russell, and then Kripke, had things to say about that. |
| 14075 | Proper name in modal contexts refer obliquely, to their usual sense [Frege, by Gibbard] |
| Full Idea: According to Frege, a proper name in a modal context refers obliquely; its reference there is its usual sense. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Allan Gibbard - Contingent Identity V | |
| A reaction: [he cites the fourth page of Frege's 'Sense and Reference'] One can foresee problems with the word 'usual' here. Frege might be offering something better than Kripke does here. |
| 10424 | A Fregean proper name has a sense determining an object, instead of a concept [Frege, by Sainsbury] |
| Full Idea: We could think of a referring expression in Fregean terms as what he calls a proper name (Eigenname): its Sinn (sense) is supposed to determine an object as opposed to a concept as its Bedeutung (referent). | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Mark Sainsbury - The Essence of Reference 18.1 | |
| A reaction: The problem would be that the same expression could precisely indicate an object on one occasion, nearly do so on another, and totally fail on a third. |
| 18773 | People may have different senses for 'Aristotle', like 'pupil of Plato' or 'teacher of Alexander' [Frege] |
| Full Idea: In the case of an actual proper name such as 'Aristotle' opinions as to the sense may differ. It might, for instance, be taken to be the following: the pupil of Plato and teacher of Alexander the Great. | |
| From: Gottlob Frege (On Sense and Reference [1892], note), quoted by Bernard Linsky - Quantification and Descriptions 1 | |
| A reaction: This note is 'notorious', and was a central target for Kripke's critique. Frege says people's senses may vary on this, and thinks the sense of 'Aristotle' can be accurately expressed. |
| 4978 | The meaning of a proper name is the designated object [Frege] |
| Full Idea: The meaning of a proper name is the object itself which we designate by using it. | |
| From: Gottlob Frege (On Sense and Reference [1892], p.30) | |
| A reaction: I can't actually make sense of this. How can a physical object be identical with a meaning? What sort of thing is a 'meaning'? Meanings are just 'in the head', I suspect. |
| 10510 | Frege ascribes reference to incomplete expressions, as well as to singular terms [Frege, by Hale] |
| Full Idea: Frege ascribes reference not only to singular terms, but equally to expressions of other kinds (the various kinds of incomplete expressions). | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Bob Hale - Abstract Objects Ch.3 Intro | |
| A reaction: The incomplete expressions presumably make reference to concepts. Frege may not seem, therefore, to have a notion of reference as what plugs language into reality - except that he is presumably a platonist about concepts. |
| 18937 | If sentences have a 'sense', empty name sentences can be understood that way [Frege, by Sawyer] |
| Full Idea: Frege's theory of 'sense' showed how sentences with empty names can have meaning and be understood. One just has to grasp the sense of the sentence (the thought expressed), and this is available even in the absence of a referent for the name. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Sarah Sawyer - Empty Names 2 | |
| A reaction: My immediate reaction is that this provides a promising solution to the empty names problem, which certainly never bothered me before I started reading philosophy. Sawyer says co-reference and truth problems remain. |
| 18940 | It is a weakness of natural languages to contain non-denoting names [Frege] |
| Full Idea: Languages have the fault of containing expressions which fail to designate an object. | |
| From: Gottlob Frege (On Sense and Reference [1892], p.40) | |
| A reaction: Wrong, Frege! This is a strength of natural languages! Names are tools. It isn't a failure of your hammer if you can't find any nails. |
| 18939 | In a logically perfect language every well-formed proper name designates an object [Frege] |
| Full Idea: A logically perfect language should satisfy the conditions that every expression grammatically well constructed as a proper name out of signs already introduced shall in fact designate an object. | |
| From: Gottlob Frege (On Sense and Reference [1892], p.41) | |
| A reaction: This seems to cramp your powers of reasoning, if you must know the object to use the name ('Jack the Ripper'), and reasoning halts once you deny the object's existence ('Pegasus'), or you don't know if names co-refer ('Hesperus/Phosphorus'). |
| 19063 | Beth trees show semantics for intuitionistic logic, in terms of how truth has been established [Dummett] |
| Full Idea: Beth trees give a semantics for intuitionistic logic, by representing sentence meaning in terms of conditions under which it is recognised to have been established as true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) |
| 19059 | In standard views you could replace 'true' and 'false' with mere 0 and 1 [Dummett] |
| Full Idea: Nothing is lost, on this view, if in the standard semantic treatment of classical sentential logic, we replace the standard truth-values 'true' and 'false' by the numbers 0 and 1. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: [A long context will explain 'on this view'] He is discussing the relationship of syntactic and semantic consequence, and goes on to criticise simple binary truth-table accounts of connectives. Semantics on a computer would just be 0 and 1. |
| 19062 | Classical two-valued semantics implies that meaning is grasped through truth-conditions [Dummett] |
| Full Idea: The standard two-valued semantics for classical logic involves a conception under which to grasp the meaning of a sentence is to apprehend the conditions under which it is, or is not, true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) | |
| A reaction: The idea is that you only have to grasp the truth tables for sentential logic, and that needs nothing more than knowing whether a sentence is true or false. I'm not sure where the 'conditions' creep in, though. |
| 9462 | Frege is intensionalist about reference, as it is determined by sense; identity of objects comes first [Frege, by Jacquette] |
| Full Idea: Intensionalism of reference is owing to Frege (in his otherwise extensionalist philosophy of language). Sense determines reference, so intension determines extension. An object must first satisfy identity requirements, and is thus in a set. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Dale Jacquette - Intro to 'Philosophy of Logic' §4 | |
| A reaction: The notion that identity of objects comes first sounds right - you can't just take objects as basic - they have to be individuated in order to be discussed. |
| 18936 | Frege moved from extensional to intensional semantics when he added the idea of 'sense' [Frege, by Sawyer] |
| Full Idea: Frege moved from an extensional semantic theory (that countenances only linguistic expressions and their referents) to an intensional theory that invokes in addition a notion of sense. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Sarah Sawyer - Empty Names 2 | |
| A reaction: This was because of Frege's famous 'puzzles', such as the morning/evening star. Quine loudly proclaimed himself an 'extensionalist', implying that he had extensional solutions for Frege's Puzzles. |
| 19065 | Soundness and completeness proofs test the theory of meaning, rather than the logic theory [Dummett] |
| Full Idea: A proof of soundess or completeness is a test, not so much of the logical theory to which it applies, but of the theory of meaning which underlies the semantics. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.310) | |
| A reaction: These two types of proof concern how the syntax and the semantics match up, so this claim sounds plausible, though I tend to think of them as more like roadworthiness tests for logic, checking how well they function. |
| 10245 | One geometry cannot be more true than another [Poincaré] |
| Full Idea: One geometry cannot be more true than another; it can only be more convenient. | |
| From: Henri Poincaré (Science and Method [1908], p.65), quoted by Stewart Shapiro - Philosophy of Mathematics | |
| A reaction: This is the culminating view after new geometries were developed by tinkering with Euclid's parallels postulate. |
| 10533 | We can't get a semantics from nouns and predicates referring to the same thing [Frege, by Dummett] |
| Full Idea: Frege is denying that on a traditional basis we can construct a workable semantics for a language; we can't regard terms like 'wisdom' as standing for the very same thing as the predicate 'x is wise' stands for. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Michael Dummett - Frege Philosophy of Language (2nd ed) Ch.14 | |
| A reaction: This follows from Idea 10532, indicating how to deal with the problem of universals. So predicates refer to concepts, and singular terms to objects. But I see no authoritative way of deciding which is which, given that paraphrases are possible. |
| 4893 | Frege was asking how identities could be informative [Frege, by Perry] |
| Full Idea: A problem which Frege called to our attention is: how can identities be informative? | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by John Perry - Knowledge, Possibility and Consciousness §5.2 | |
| A reaction: E.g. (in Russell's example) how is "Scott is the author of 'Waverley'" more informative than "Scott is Scott"? A simple answer might just be that informative identities also tell you of a thing's properties. "The red ball is the heavy ball". |
| 19061 | An explanation is often a deduction, but that may well beg the question [Dummett] |
| Full Idea: An explanation is often a deductive argument, with the fact needing explaining as its conclusion. ...But the conclusion is usually given in advance, and we may only believe the premisses because they plausibly explain the conclusion. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.296) | |
| A reaction: [compressed (Dummett's wordy prose cries out for it!)] I suppose this works better in mathematics, which is central to Dummett's interests. In the real world the puzzle is not usually logically implied by its explanation. |
| 18752 | 'The concept "horse"' denotes a concept, yet seems also to denote an object [Frege, by McGee] |
| Full Idea: The phrase 'the concept "horse"' can be the subject of a sentence, and ought to denote an object. But it clearly denotes the concept "horse". Yet Fregean concepts are said to be 'incomplete' objects, which led to confusion. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Vann McGee - Logical Consequence 4 | |
| A reaction: This is the notorious 'concept "horse"' problem, which was bad news for Frege's idea of a concept. |
| 22318 | Frege failed to show when two sets of truth-conditions are equivalent [Frege, by Potter] |
| Full Idea: Frege's account suffered from a lack of precision about when two sets of truth-conditions should count as equivalent. (Wittgenstein aimed to rectify this defect). | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 50 Intro |
| 4980 | The meaning (reference) of a sentence is its truth value - the circumstance of it being true or false [Frege] |
| Full Idea: We are driven into accepting the truth-value of a sentence as constituting what it means (refers to). By the truth-value I understand the circumstance that it is true or false. | |
| From: Gottlob Frege (On Sense and Reference [1892], p.34) | |
| A reaction: Sounds bizarre, but Black's translation doesn't help. The notion of what the whole sentence refers to (rather than its sense) is a very theoretical notion. 'All true sentences refer to the truth' sounds harmless enough. |
| 9180 | Holism says all language use is also a change in the rules of language [Frege, by Dummett] |
| Full Idea: Frege thought of a language as a game played with fixed rules, there being all the difference in the world between a move in the game and an alteration of the rules; but, if holism is correct, every move in the game changes the rules. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Michael Dummett - Frege's Distinction of Sense and Reference p.248 | |
| A reaction: Rules do shift over time, so there must be some mechanism for that - the rules can't sit in sacrosanct isolation. People play games with the language itself, as well as using it to play other games. |
| 19064 | Holism is not a theory of meaning; it is the denial that a theory of meaning is possible [Dummett] |
| Full Idea: In the sense of giving a model for the content of a sentence, its representative power, holism is not a theory of meaning; it is the denial that a theory of meaning is possible. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.309) | |
| A reaction: This will obviously be because sentences just don't have meaning in isolation, so their meaning can't be given in terms of the sentences. |
| 4981 | The reference of a word should be understood as part of the reference of the sentence [Frege] |
| Full Idea: I have transferred the relation between the parts and the whole of the sentence to its reference, by calling the reference of the word part of the reference of the sentence, if the word itself is part of the sentence. | |
| From: Gottlob Frege (On Sense and Reference [1892], p.35) | |
| A reaction: Since Frege says the reference of a true sentence is simply to truth, words have reference insofar as they make contributions to attempts at stating truths. |
| 17002 | Frege's 'sense' is ambiguous, between the meaning of a designator, and how it fixes reference [Kripke on Frege] |
| Full Idea: Frege should be criticised for using the term 'sense' in two senses. He takes the sense of a designator to be its meaning; and he also takes it to be the way its reference is determined. …They correspond to two ordinary uses of 'definition'. | |
| From: comment on Gottlob Frege (On Sense and Reference [1892]) by Saul A. Kripke - Naming and Necessity lectures Lecture 1 | |
| A reaction: Stalnaker quotes this, but seems unconvinced that Frege is guilty. If the 'meaning' largely consists of a way of determining a reference, Frege would be in the clear. |
| 18778 | Every descriptive name has a sense, but may not have a reference [Frege] |
| Full Idea: It may perhaps be granted that every grammatically well-formed expression representing a proper name always has a sense. But this is not to say that to this sense there also corresponds a reference. | |
| From: Gottlob Frege (On Sense and Reference [1892]), quoted by Bernard Linsky - Quantification and Descriptions 3.1 | |
| A reaction: Presumably this concerns fictional names such as 'Pegasus'. It seems to be good simple evidence for the distinction between sense and reference. |
| 7805 | Frege started as anti-realist, but the sense/reference distinction led him to realism [Frege, by Benardete,JA] |
| Full Idea: In the Grundlagen of 1884 Frege was an anti-realist, but in Grundgesetze of 1893 he is a realist, who has profited by his interim discovery of the sense/reference distinction. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by José A. Benardete - Logic and Ontology | |
| A reaction: This is the germ of the new realist philosophy which seems to be growing out of Kripke and co's causal theory of reference. The very notion of reference is realist (hence Russell's realism). |
| 4976 | The meaning (reference) of 'evening star' is the same as that of 'morning star', but not the sense [Frege] |
| Full Idea: The meaning (reference) of 'evening star' is the same as that of 'morning star', but not the sense. | |
| From: Gottlob Frege (On Sense and Reference [1892], p.27) | |
| A reaction: Max Black translates 'bedeutung' as 'meaning', but nowadays everyone calls it 'reference'. This is Frege's crucial distinction, which greatly clarified analytical philosophy. Nevertheless, is it a sharp distinction? E.g. referring to a fictional name? |
| 4977 | In maths, there are phrases with a clear sense, but no actual reference [Frege] |
| Full Idea: The expression 'the least rapidly convergent series' has a sense but demonstrably there is no reference, since a less rapidly convergent series (for any given series) can always be found. | |
| From: Gottlob Frege (On Sense and Reference [1892], p.28) | |
| A reaction: A nice example. 'The second Kennedy assassin' has a clear meaning, but does it have a reference? The meaning 'points at' a possible reference. We yet discover an identity. |
| 4979 | We are driven from sense to reference by our desire for truth [Frege] |
| Full Idea: The striving for truth drives us always to advance from the sense to the thing meant (the reference). | |
| From: Gottlob Frege (On Sense and Reference [1892], p.33) | |
| A reaction: As in, we want to know the reference of 'the person who shot Kennedy'. I always perk up if truth is mentioned in a discussion of language, because it reminds us of the point of the whole thing. In 'Is he the best man?' I have the reference, not the truth. |
| 15597 | Frege's Puzzle: from different semantics we infer different reference for two names with the same reference [Frege, by Fine,K] |
| Full Idea: Frege's Puzzle: If two sentences convey different information, they have different semantic roles, so the names 'Cicero' and 'Tully' are semantically different, in which case they are referentially different - but they are not referentially different. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Kit Fine - Semantic Relationism 2.A | |
| A reaction: [this is my summary of Fine's summary] Given the paradox, the question is which of these premisses should be challenged. Fregeans reject their being referentially different. Referentialists reject the different semantic roles. |
| 15155 | Expressions always give ways of thinking of referents, rather than the referents themselves [Frege, by Soames] |
| Full Idea: For Frege, expressions always contribute ways of thinking of their referents, rather than the referents themselves, to the thoughts expressed by sentences. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Scott Soames - Philosophy of Language 1.16 | |
| A reaction: I have some sympathy for Frege. It always strikes me as daft to think that if I say 'my dustbin is empty', the dustbin becomes 'part' of my sentence. Sentences don't contain large plastic objects. |
| 11126 | 'Sense' gives meaning to non-referring names, and to two expressions for one referent [Frege, by Margolis/Laurence] |
| Full Idea: Frege notes that an expression without a referent ('Pegasus') needn't lack a meaning, since it still has a sense, and the same referent (Eric Blair) can be associated with different expressions (George Orwell) because they convey different senses. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by E Margolis/S Laurence - Concepts 1.3 | |
| A reaction: A nice neat summary of the value of Frege's introduction of the sense/reference distinction, which seems to me to be virtually undeniable (a rare event in modern philosophy). |
| 8164 | Frege was the first to construct a plausible theory of meaning [Frege, by Dummett] |
| Full Idea: Frege was the first to construct a plausible theory of meaning, that is, a theory of how a human language functions. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Michael Dummett - Thought and Reality 1 | |
| A reaction: Presumably Frege had an advantage because he was the first to distinguish sense from reference, and hence to identify the subject-matter of the theory. Essentially Frege's theory is that of truth-conditions. |
| 9817 | Earlier Frege focuses on content itself; later he became interested in understanding content [Frege, by Dummett] |
| Full Idea: Earlier Frege was interested solely in the content of our statements, not in our grasp of that content. His notion of 'sense' from 1891 onwards, has to do with understanding; the sense of an expression is something we grasp. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Michael Dummett - Frege philosophy of mathematics Ch.2 | |
| A reaction: The important point must be that the later theory depends on the earlier, so we can hardly give theories of understanding, if we don't have a view about what it is that is understood. |
| 8171 | Frege divided the meaning of a sentence into sense, force and tone [Frege, by Dummett] |
| Full Idea: Frege distinguished three components of the meaning of a sentence: sense, force and tone; he used no single term for 'linguistic meaning' in general. ...The sense is only what bears on the truth or falsity of what the sentence expresses. | |
| From: report of Gottlob Frege (On Sense and Reference [1892]) by Michael Dummett - Thought and Reality 3 | |
| A reaction: Modern theories of meaning seem to assume that there is one item called 'meaning' which needs to be explained, but presumably this is 'strict and literal meaning', leaving the rest to pragmatics. |
| 4954 | Frege uses 'sense' to mean both a designator's meaning, and the way its reference is determined [Kripke on Frege] |
| Full Idea: Frege should be criticised for using the term 'sense' in two senses. For he takes the sense of a designator to be its meaning; and he also takes it to be the way its reference is determined. | |
| From: comment on Gottlob Frege (On Sense and Reference [1892]) by Saul A. Kripke - Naming and Necessity lectures Lecture 1 | |
| A reaction: This criticism doesn't surprise me, as heroic pioneers like Frege seem to have been extremely unclear about what they were claiming. Kripke has helped, but we still need some great mind to step in and sort out the mess. |
| 7304 | Frege explained meaning as sense, semantic value, reference, force and tone [Frege, by Miller,A] |
| Full Idea: Frege analysed the intuitive notion of meaning in terms of the notions of sense, semantic value, reference, force and tone. | |
| From: report of Gottlob Frege (On Sense and Reference [1892], Pref) by Alexander Miller - Philosophy of Language Pref | |
| A reaction: This suggests that there are two approaches to the explanation of meaning: either a simple identity with some other mental fact, or an analysis (as here) into a range of components. I remain open-minded on that. |