18 ideas
13734 | Modern Quinean metaphysics is about what exists, but Aristotelian metaphysics asks about grounding [Schaffer,J] |
Full Idea: On the now dominant Quinean view, metaphysics is about what there is (such as properties, meanings and numbers). I will argue for the revival of a more traditional Aristotelian view, on which metaphysics is about what grounds what. | |
From: Jonathan Schaffer (On What Grounds What [2009], Intro) | |
A reaction: I find that an enormously helpful distinction, and support the Aristotelian view. Schaffer's general line is that what exists is fairly uncontroversial and dull, but the interesting truths about the world emerge when we grasp its structure. |
13751 | If you tore the metaphysics out of philosophy, the whole enterprise would collapse [Schaffer,J] |
Full Idea: Traditional metaphysics is so tightly woven into the fabric of philosophy that it cannot be torn out without the whole tapestry unravelling. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.3) | |
A reaction: I often wonder why the opponents of metaphysics still continue to do philosophy. I don't see how you address questions of ethics, or philosophy of mathematics (etc) without coming up against highly general and abstract over-questions. |
13743 | We should not multiply basic entities, but we can have as many derivative entities as we like [Schaffer,J] |
Full Idea: Occam's Razor should only be understood to concern substances: do not multiply basic entities without necessity. There is no problem with the multiplication of derivative entities - they are an 'ontological free lunch'. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
A reaction: The phrase 'ontological free lunch' comes from Armstrong. This is probably what Occam meant. A few extra specks of dust, or even a few more numbers (thank you, Cantor!) don't seem to challenge the principle. |
18812 | Split out the logical vocabulary, make an assignment to the rest. It's logical if premises and conclusion match [Tarski, by Rumfitt] |
Full Idea: Tarski made a division of logical and non-logical vocabulary. He then defined a model as a non-logical assignment satisfying the corresponding sentential function. Then a conclusion follows logically if every model of the premises models the conclusion. | |
From: report of Alfred Tarski (The Concept of Logical Consequence [1936]) by Ian Rumfitt - The Boundary Stones of Thought 3.2 | |
A reaction: [compressed] This is Tarski's account of logical consequence, which follows on from his account of truth. 'Logical validity' is then 'true in every model'. Rumfitt doubts whether Tarski has given the meaning of 'logical consequence'. |
13344 | X follows from sentences K iff every model of K also models X [Tarski] |
Full Idea: The sentence X follows logically from the sentences of the class K if and only if every model of the class K is also a model of the sentence X. | |
From: Alfred Tarski (The Concept of Logical Consequence [1936], p.417) | |
A reaction: [see Idea 13343 for his account of a 'model'] He is offering to define logical consequence in general, but this definition fits what we now call 'semantic consequence', written |=. This it is standard practice to read |= as 'models'. |
13343 | A 'model' is a sequence of objects which satisfies a complete set of sentential functions [Tarski] |
Full Idea: An arbitrary sequence of objects which satisfies every sentential function of the sentences L' will be called a 'model' or realization of the class L of sentences. There can also be a model of a single sentence is this way. | |
From: Alfred Tarski (The Concept of Logical Consequence [1936], p.417) | |
A reaction: [L' is L with the constants replaced by variables] Tarski is the originator of model theory, which is central to modern logic. The word 'realization' is a helpful indicator of what he has in mind. A model begins to look like a possible world. |
13741 | If 'there are red roses' implies 'there are roses', then 'there are prime numbers' implies 'there are numbers' [Schaffer,J] |
Full Idea: We can automatically infer 'there are roses' from 'there are red roses' (with no shift in the meaning of 'roses'). Likewise one can automatically infer 'there are numbers' from 'there are prime numbers'. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
A reaction: He similarly observes that the atheist's 'God is a fictional character' implies 'there are fictional characters'. Schaffer is not committing to a strong platonism with his claim - merely that the existence of numbers is hardly worth disputing. |
13748 | Grounding is unanalysable and primitive, and is the basic structuring concept in metaphysics [Schaffer,J] |
Full Idea: Grounding should be taken as primitive, as per the neo-Aristotelian approach. Grounding is an unanalyzable but needed notion - it is the primitive structuring conception of metaphysics. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.2) | |
A reaction: [he cites K.Fine 1991] I find that this simple claim clarifies the discussions of Kit Fine, where you are not always quite sure what the game is. I agree fully with it. It makes metaphysics interesting, where cataloguing entities is boring. |
13747 | Supervenience is just modal correlation [Schaffer,J] |
Full Idea: Supervenience is mere modal correlation. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.2) |
13744 | The cosmos is the only fundamental entity, from which all else exists by abstraction [Schaffer,J] |
Full Idea: My preferred view is that there is only one fundamental entity - the whole concrete cosmos - from which all else exists by abstraction. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
A reaction: This looks to me like weak anti-realism - that there are no natural 'joints' in nature - but I don't think Schaffer intends that. I take the joints to be fundamentals, which necessitates that the cosmos has parts. His 'abstraction' is clearly a process. |
13739 | Maybe categories are just the different ways that things depend on basic substances [Schaffer,J] |
Full Idea: Maybe the categories are determined by the different grounding relations, ..so that categories just are the ways things depend on substances. ...Categories are places in the dependence ordering. | |
From: Jonathan Schaffer (On What Grounds What [2009], 1.3) |
13742 | There exist heaps with no integral unity, so we should accept arbitrary composites in the same way [Schaffer,J] |
Full Idea: I am happy to accept universal composition, on the grounds that there are heaps, piles etc with no integral unity, and that arbitrary composites are no less unified than heaps. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.1 n11) | |
A reaction: The metaphysical focus is then placed on what constitutes 'integral unity', which is precisely the question which most interested Aristotle. Clearly if there is nothing more to an entity than its components, scattering them isn't destruction. |
13752 | The notion of 'grounding' can explain integrated wholes in a way that mere aggregates can't [Schaffer,J] |
Full Idea: The notion of grounding my capture a crucial mereological distinction (missing from classical mereology) between an integrated whole with genuine unity, and a mere aggregate. x is an integrated whole if it grounds its proper parts. | |
From: Jonathan Schaffer (On What Grounds What [2009], 3.1) | |
A reaction: That gives a nice theoretical notion, but if you remove each of the proper parts, does x remain? Is it a bare particular? I take it that it will have to be an abstract principle, the one Aristotle was aiming at with his notion of 'form'. Schaffer agrees. |
13749 | Belief in impossible worlds may require dialetheism [Schaffer,J] |
Full Idea: One motivation for dialetheism is the view that there are impossible worlds. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.3) |
13740 | 'Moorean certainties' are more credible than any sceptical argument [Schaffer,J] |
Full Idea: A 'Moorean certainty' is when something is more credible than any philosopher's argument to the contrary. | |
From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
A reaction: The reference is to G.E. Moore's famous claim that the existence of his hand is more certain than standard sceptical arguments. It sounds empiricist, but they might be parallel rational truths, of basic logic or arithmetic. |
3161 | If mind is just an explanation, the explainer must have beliefs [Rey on Dennett] |
Full Idea: If something has beliefs only if something else is disposed to "treat it" (i.e. think of it) as though it does, then we seem at least to have an infinite regress of appeals to believers. | |
From: comment on Daniel C. Dennett (works [1985]) by Georges Rey - Contemporary Philosophy of Mind 3.2.1 | |
A reaction: This sounds like a serious difficulty for behaviourists, but is not insurmountable. We need a community of interlocking behaviours, with a particular pattern of behaviour being labelled (for instrumental convenience) as 'beliefs'. |
3177 | You couldn't drive a car without folk psychology [Dennett] |
Full Idea: Folk psychology is indispensable for driving a car, which would be terrifying if we didn't assume there were psychologically normal people behind the wheels. | |
From: Daniel C. Dennett (works [1985]), quoted by Georges Rey - Contemporary Philosophy of Mind p.133 n35 | |
A reaction: Nice example. If someone is approaching you from the front on your side of the road, should you assume that they are 'psychologically normal'? Does psychology imply behaviour, or vice versa? |
13345 | Sentences are 'analytical' if every sequence of objects models them [Tarski] |
Full Idea: A class of sentences can be called 'analytical' if every sequence of objects is a model of it. | |
From: Alfred Tarski (The Concept of Logical Consequence [1936], p.418) | |
A reaction: See Idea 13344 and Idea 13343 for the context of this assertion. |