23 ideas
| 18806 | Frege thought traditional categories had psychological and linguistic impurities [Frege, by Rumfitt] |
| Full Idea: Frege rejected the traditional categories as importing psychological and linguistic impurities into logic. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by Ian Rumfitt - The Boundary Stones of Thought 1.2 | |
| A reaction: Resisting such impurities is the main motivation for making logic entirely symbolic, but it doesn't follow that the traditional categories have to be dropped. |
| 8490 | First-level functions have objects as arguments; second-level functions take functions as arguments [Frege] |
| Full Idea: Just as functions are fundamentally different from objects, so also functions whose arguments are and must be functions are fundamentally different from functions whose arguments are objects. The latter are first-level, the former second-level, functions. | |
| From: Gottlob Frege (Function and Concept [1891], p.38) | |
| A reaction: In 1884 he called it 'second-order'. This is the standard distinction between first- and second-order logic. The first quantifies over objects, the second over intensional entities such as properties and propositions. |
| 8492 | Relations are functions with two arguments [Frege] |
| Full Idea: Functions of one argument are concepts; functions of two arguments are relations. | |
| From: Gottlob Frege (Function and Concept [1891], p.39) | |
| A reaction: Nowadays we would say 'two or more'. Another interesting move in the aim of analytic philosophy to reduce the puzzling features of the world to mathematical logic. There is, of course, rather more to some relations than being two-argument functions. |
| 7755 | Singular terms refer, using proper names, definite descriptions, singular personal pronouns, demonstratives, etc. [Lycan] |
| Full Idea: The paradigmatic referring devices are singular terms, denoting particular items. In English these include proper names, definite descriptions, singular personal pronouns, demonstrative pronouns, and a few others. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 1) | |
| A reaction: This list provides the agenda for twentieth century philosophy of language, since this is the point where language is supposed to hook onto the world. |
| 8487 | Arithmetic is a development of logic, so arithmetical symbolism must expand into logical symbolism [Frege] |
| Full Idea: I am of the opinion that arithmetic is a further development of logic, which leads to the requirement that the symbolic language of arithmetic must be expanded into a logical symbolism. | |
| From: Gottlob Frege (Function and Concept [1891], p.30) | |
| A reaction: This may the the one key idea at the heart of modern analytic philosophy (even though logicism may be a total mistake!). Logic and arithmetical foundations become the master of ontology, instead of the servant. The jury is out on the whole enterprise. |
| 18899 | Frege takes the existence of horses to be part of their concept [Frege, by Sommers] |
| Full Idea: Frege regarded the existence of horses as a property of the concept 'horse'. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by Fred Sommers - Intellectual Autobiography 'Realism' |
| 4028 | Frege allows either too few properties (as extensions) or too many (as predicates) [Mellor/Oliver on Frege] |
| Full Idea: Frege's theory of properties (which he calls 'concepts') yields too few properties, by identifying coextensive properties, and also too many, by letting every predicate express a property. | |
| From: comment on Gottlob Frege (Function and Concept [1891]) by DH Mellor / A Oliver - Introduction to 'Properties' §2 | |
| A reaction: Seems right; one extension may have two properties (have heart/kidneys), two predicates might express the same property. 'Cutting nature at the joints' covers properties as well as objects. |
| 8489 | The concept 'object' is too simple for analysis; unlike a function, it is an expression with no empty place [Frege] |
| Full Idea: I regard a regular definition of 'object' as impossible, since it is too simple to admit of logical analysis. Briefly: an object is anything that is not a function, so that an expression for it does not contain any empty place. | |
| From: Gottlob Frege (Function and Concept [1891], p.32) | |
| A reaction: Here is the core of the programme for deriving our ontology from our logic and language, followed through by Russell and Quine. Once we extend objects beyond the physical, it becomes incredibly hard to individuate them. |
| 7388 | McGinn invites surrender, by saying it is hopeless trying to imagine conscious machines [Dennett on McGinn] |
| Full Idea: McGinn invites his readers to join him in surrender: It's just impossible to imagine how software could make a conscious robot. Don't even try, he says. Other philosophical experiments (involving China) "work" by dissuading readers from imagining. | |
| From: comment on Colin McGinn (The Problem of Consciousness [1991]) by Daniel C. Dennett - Consciousness Explained 14.1 | |
| A reaction: I agree with Dennett. If you don't try to imagine how robots might do it, you are also denied the right to try to imagine how brains might manage it. Admittedly this is hard, but good imagination needs study, effort, discussion, time, information... |
| 3185 | Multiple realisability rules out hidden essences and experts as the source of water- and gold-concepts [McGinn] |
| Full Idea: The multiple realisability emphasised by functionalists rules out the hidden essences (and the 'deferential' move in semantics) that one finds in the cases, for example, of "water" and "gold" emphasised by Kripke and Putnam. | |
| From: Colin McGinn (The Problem of Consciousness [1991], p.132) | |
| A reaction: Presumably if they are 'hidden', then the people to whom we 'defer' for our concepts can't actually know about the essences we are supposed to be discussing. You can mean essences without knowing them. Cf. Loch Ness Monster. |
| 9947 | Concepts are the ontological counterparts of predicative expressions [Frege, by George/Velleman] |
| Full Idea: Concepts, for Frege, are the ontological counterparts of predicative expressions. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.2 | |
| A reaction: That sounds awfully like what many philosophers call 'universals'. Frege, as a platonist (at least about numbers), I would take to be in sympathy with that. At least we can say that concepts seem to be properties. |
| 10319 | An assertion about the concept 'horse' must indirectly speak of an object [Frege, by Hale] |
| Full Idea: Frege had a notorious difficulty over the concept 'horse', when he suggests that if we wish to assert something about a concept, we are obliged to proceed indirectly by speaking of an object that represents it. | |
| From: report of Gottlob Frege (Function and Concept [1891], Ch.2.II) by Bob Hale - Abstract Objects | |
| A reaction: This sounds like the thin end of a wedge. The great champion of objects is forced to accept them here as a façon de parler, when elsewhere they have ontological status. |
| 8488 | A concept is a function whose value is always a truth-value [Frege] |
| Full Idea: A concept in logic is closely connected with what we call a function. Indeed, we may say at once: a concept is a function whose value is always a truth-value. ..I give the name 'function' to what is meant by the 'unsaturated' part. | |
| From: Gottlob Frege (Function and Concept [1891], p.30) | |
| A reaction: So a function becomes a concept when the variable takes a value. Problems arise when the value is vague, or the truth-value is indeterminable. |
| 9948 | Unlike objects, concepts are inherently incomplete [Frege, by George/Velleman] |
| Full Idea: For Frege, concepts differ from objects in being inherently incomplete in nature. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.2 | |
| A reaction: This is because they are 'unsaturated', needing a quantified variable to complete the sentence. This could be a pointer towards Quine's view of properties, as simply an intrinsic feature of predication about objects, with no separate identity. |
| 7768 | The truth conditions theory sees meaning as representation [Lycan] |
| Full Idea: The truth conditions theory sees meaning as representation. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 9) | |
| A reaction: This suggests a nice connection to Fodor's account of intentional thinking. The whole package sounds right to me (though the representations need not be 'symbolic', or in mentalese). |
| 7766 | Meaning must be known before we can consider verification [Lycan] |
| Full Idea: How could we know whether a sentence is verifiable unless we already knew what it says? | |
| From: William Lycan (Philosophy of Language [2000], Ch. 8) | |
| A reaction: This strikes me as a devastating objection to verificationism. Lycan suggests that you can formulate a preliminary meaning, without accepting true meaningfulness. Maybe verification just concerns truth, and not meaning. |
| 7764 | Could I successfully use an expression, without actually understanding it? [Lycan] |
| Full Idea: Could I not know the use of an expression and fall in with it, mechanically, but without understanding it? | |
| From: William Lycan (Philosophy of Language [2000], Ch. 6) | |
| A reaction: In a foreign country, you might successfully recite a long complex sentence, without understanding a single word. This doesn't doom the 'use' theory, but it means that quite a lot of detail needs to be filled in. |
| 7763 | It is hard to state a rule of use for a proper name [Lycan] |
| Full Idea: Proper names pose a problem for the "use" theorist. Try stating a rule of use for the name 'William G. Lycan'. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 6) | |
| A reaction: Presumably it is normally used in connection with a particular human being, and is typically the subject of a grammatical sentence. Any piece of language could also be used to, say, attract someone's attention. |
| 4972 | I may regard a thought about Phosphorus as true, and the same thought about Hesperus as false [Frege] |
| Full Idea: From sameness of meaning there does not follow sameness of thought expressed. A fact about the Morning Star may express something different from a fact about the Evening Star, as someone may regard one as true and the other false. | |
| From: Gottlob Frege (Function and Concept [1891], p.14) | |
| A reaction: This all gets clearer if we distinguish internalist and externalist theories of content. Why take sides on this? Why not just ask 'what is in the speaker's head?', 'what does the sentence mean in the community?', and 'what is the corresponding situation?' |
| 7770 | Truth conditions will come out the same for sentences with 'renate' or 'cordate' [Lycan] |
| Full Idea: A Davidsonian truth theory will not be able to distinguish the meaning of a sentence containing 'renate' from that of one containing 'cordate'. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 9) | |
| A reaction: One might achieve the distinction by referring to truth conditions in possible worlds, if there are possible worlds where some cordates are not renate. See Idea 7773. |
| 7773 | A sentence's truth conditions is the set of possible worlds in which the sentence is true [Lycan] |
| Full Idea: A sentence's truth conditions can be taken to be the set of possible worlds in which the sentence is true. | |
| From: William Lycan (Philosophy of Language [2000], Ch.10) | |
| A reaction: Presumably the meaning can't be complete possible worlds, so this must be a supplement to the normal truth conditions view proposed by Davidson. It particularly addresses the problem seen in Idea 7770. |
| 7774 | Possible worlds explain aspects of meaning neatly - entailment, for example, is the subset relation [Lycan] |
| Full Idea: The possible worlds construal affords an elegant algebra of meaning by way of set theory: e.g. entailment between sentences is just the subset relation - S1 entails S2 if S2 is true in any world in which S1 is true. | |
| From: William Lycan (Philosophy of Language [2000], Ch.10) | |
| A reaction: We might want to separate the meanings of sentences from their entailments (though Brandom links them, see Idea 7765). |
| 8491 | The Ontological Argument fallaciously treats existence as a first-level concept [Frege] |
| Full Idea: The ontological proof of God's existence suffers from the fallacy of treating existence as a first-level concept. | |
| From: Gottlob Frege (Function and Concept [1891], p.38 n) | |
| A reaction: [See Idea 8490 for first- and second-order functions] This is usually summarised as the idea that existence is a quantifier rather than a predicate. |