24 ideas
| 6855 | Interesting philosophers hardly every give you explicitly valid arguments [Martin,M] |
| Full Idea: Notice that very few philosophers - certainly almost none of the ones who are interesting to read - give you explicitly valid arguments. | |
| From: Michael Martin (Interview with Baggini and Stangroom [2001], p.134) | |
| A reaction: I never thought that was going to happen in philosophy. What I do get is, firstly, lots of interesting reasons for holding beliefs, and a conviction that good beliefs need good reasons, and, secondly, a really coherent view of the world. |
| 6856 | Valid arguments can be rejected by challenging the premises or presuppositions [Martin,M] |
| Full Idea: Putting forward a valid argument isn't necessarily going to succeed in getting someone to see things your way, because if they don't accept the conclusion, they ask which premises they should reject, or whether an illegitimate assumption is being made. | |
| From: Michael Martin (Interview with Baggini and Stangroom [2001], p.136) | |
| A reaction: Valid arguments are still vital. It is just that good philosophers realise the problem noted here, and spend huge stretches of discussion on establishing acceptance of premises, and showing that there are no dodgy presuppositions. |
| 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. |
| 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. |
| 6857 | An error theory of perception says our experience is not as it seems to be [Martin,M] |
| Full Idea: You can end up with an error theory of perception, which says our experience is not as it seems to be, as bizarre as that might be. | |
| From: Michael Martin (Interview with Baggini and Stangroom [2001], p.140) | |
| A reaction: This is because of the clash between subjective and objective aspects of perception. It is an enticing proposal, just the sort of thing I pay philosophers to come up with. Given oddities like blindsight, I think it should be taken seriously. |
| 7440 | Secondary qualities are microscopic primary qualities of physical things [Armstrong] |
| Full Idea: I argue for the direct identification of the secondary qualities with microscopic primary qualities of physical things. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xxii) | |
| A reaction: This sounds a bit like the eliminativism which Armstrong rejects. This seems in danger of mixing questions about the nature of mental events with questions about the nature of externally perceived objects. |
| 7437 | Consciousness and experience of qualities are not the same [Armstrong] |
| Full Idea: Consciousness and experience of qualities are often run together - a serious mistake, I think. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvii) | |
| A reaction: A difficult claim to evaluate. Can we experience redness without being conscious of it? Could there be consciousness (e.g. of concepts) which didn't involve any qualities? I suspect that qualities are more basic than intentionality or consciousness. |
| 7434 | Behaviourism is false, but mind is definable as the cause of behaviour [Armstrong] |
| Full Idea: Behaviourism is false, but one is not far from the truth if one defines the mind as the cause of behaviour. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvi) | |
| A reaction: As Putnam says, if you cut all the efferent (outgoing) nerves, you would have a mind with no behaviour at all. I would say my mind is full of stuff that never affects my behaviour. However, influencing behaviour is certainly the main function of a mind. |
| 7436 | The manifestations of a disposition need never actually exist [Armstrong] |
| Full Idea: The manifestations of a disposition have the particularly mysterious property (metaphysically speaking) that they need not exist - which makes them rather like intentional objects. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvii) | |
| A reaction: His example is a brittle glass which never shatters. This problem seems to require the mention of conditional and counterfactual statements in the description of the actual world, which rather increases the workload for philosophers. |
| 7429 | Causal Functionalism says mental states are apt for producing behaviour [Armstrong] |
| Full Idea: I speak of my view as the Causal version of functionalism, which asserts that mental states are states apt for the production of certain ranges of behaviour and, in some cases, apt for being produced by certain ranges of stimuli. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xiv) | |
| A reaction: This effectively makes a mental state a place in a flowdiagram (and hence the mind is software). It says nothing about what qualities the mental states have which make them apt for this role. Full explanations need more than the function. |
| 7438 | A causal theory of mentality would be improved by a teleological element [Armstrong] |
| Full Idea: I now think, following Lycan, that my Causal theory of mentality would be strengthened (perhaps eliminating some potential counter-examples) by the addition of a teleological element. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xviii) | |
| A reaction: For Lycan, see Idea 6533. Armstrong has begun to realise that merely specifying the causal role of a mental state is too thin as an explanation. Teleology widens the notion of function. I also want to know about the properties that make it possible. |
| 7431 | The identity of mental states with physical properties is contingent, because the laws of nature are contingent [Armstrong] |
| Full Idea: Granted the contingency of the laws of nature, the identification of dispositions with their categorical bases can be contingent only. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvi) | |
| A reaction: Personally I am not willing to grant the contingency of the laws of nature, but I suppose Armstrong is right about identity if he is right about laws. Presumably an identity could happen to be invariant across possible worlds, without being necessary. |
| 7432 | One mental role might be filled by a variety of physical types [Armstrong] |
| Full Idea: If the mental is just that which plays a causal role then there is the possibility, which may even be an empirical possibility, that the causal role of tokens of the same mental type should be filled by tokens of significantly different physical types. | |
| From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xiv) | |
| A reaction: This allows for multiple realisability in a physicalist framework. Fear has the same role in all animals, but may be realised in physically different ways. I go further, and say that two mental states could differ, while playing the same role. |
| 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. |
| 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?' |
| 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. |