Ideas from 'On What Grounds What' by Jonathan Schaffer [2009], by Theme Structure

[found in 'Metametaphysics' (ed/tr Chalmers/Manley/Wasserman) [OUP 2009,978-0-19-954600-8]].

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1. Philosophy / E. Nature of Metaphysics / 1. Nature of Metaphysics
Modern Quinean metaphysics is about what exists, but Aristotelian metaphysics asks about grounding
                        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.
1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
If you tore the metaphysics out of philosophy, the whole enterprise would collapse
                        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.
2. Reason / B. Laws of Thought / 6. Ockham's Razor
We should not multiply basic entities, but we can have as many derivative entities as we like
                        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.
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
If 'there are red roses' implies 'there are roses', then 'there are prime numbers' implies 'there are numbers'
                        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.
7. Existence / C. Structure of Existence / 1. Grounding / a. Nature of grounding
Grounding is unanalysable and primitive, and is the basic structuring concept in metaphysics
                        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.
7. Existence / C. Structure of Existence / 5. Supervenience / a. Nature of supervenience
Supervenience is just modal correlation
                        Full Idea: Supervenience is mere modal correlation.
                        From: Jonathan Schaffer (On What Grounds What [2009], 2.2)
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
The cosmos is the only fundamental entity, from which all else exists by abstraction
                        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.
7. Existence / E. Categories / 4. Category Realism
Maybe categories are just the different ways that things depend on basic substances
                        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)
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
There exist heaps with no integral unity, so we should accept arbitrary composites in the same way
                        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.
The notion of 'grounding' can explain integrated wholes in a way that mere aggregates can't
                        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.
10. Modality / E. Possible worlds / 1. Possible Worlds / b. Impossible worlds
Belief in impossible worlds may require dialetheism
                        Full Idea: One motivation for dialetheism is the view that there are impossible worlds.
                        From: Jonathan Schaffer (On What Grounds What [2009], 2.3)
11. Knowledge Aims / B. Certain Knowledge / 2. Common Sense Certainty
'Moorean certainties' are more credible than any sceptical argument
                        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.