Regularity Comparativism about Mass in Newtonian Gravity Niels C.M. - - PowerPoint PPT Presentation

Regularity Comparativism about Mass in Newtonian Gravity Niels C.M. Martens

PSA 2016 Slides available at http://users.ox.ac.uk/~corp2044

5 Nov 2016

Outline

1

The Regularity Approach Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

2

Responses It doesn’t work Separability Eliminativism

Outline

1

The Regularity Approach

2

Responses

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Humean Supervenience

“

laws are parasitic on occurent facts

Earman, 1984”

“

Humean supervenience is named in honor of the greater [sic] denier of nec- essary connections. It is the doctrine that all there is to the world is a vast mosaic of local maters of fact, just one litle thing and then another. ... We have geometry: a system of external relations of spatio-temporal dis- tances between points. Maybe points of spacetime itself, maybe pointsized bits of mater or aether fields, maybe both. And at those points we have local qualities: perfectly natural instrinsic properties which require noth- ing bigger than a point at which to be instantiated. For short: we have an arrangement of qualities. And that is all. All else supervenes on that.

Lewis, 1986”

Niels Martens Regularity Comparativism 4/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Unpacking Humean Supervenience I

• 1. Separability

“The complete physical state of the world is determined by ... the intrinsic physical state of each spacetime point (or each point-like

• bject) and the spatio-temporal relations between those points.”

(Maudlin, 2007)

Informal Gloss: “[A]ll fundamental properties are [intrinsic] properties and ... spatio-temporal relations are the only fundamental external physical relations.”

Niels Martens Regularity Comparativism 5/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Unpacking Humean Supervenience II

1.a. Strong Absolutism about all non-spatiotemporal quantities 1.a.1 Absolutism Intrinsic quantities ground the ratios between those quantities. 1.a.2 Qantity Primitivism These quantities are fundamental. (Dees, MS) 1.b. 4D-fundamentalism The four-dimensional spacetime is fundamental.

(Keming Chen, MS)

Niels Martens Regularity Comparativism 6/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Unpacking Humean Supervenience III

• 1. Separability

“The complete physical state of the world is determined by ... the intrinsic physical state of each spacetime point (or each point-like

• bject) and the spatio-temporal relations between those points.”

(Maudlin, 2007)

• 2. Supervenience

“All facts about a world, including modal and nomological facts, [supervene on] its [complete] physical state.”

(Maudlin, 2007)

Niels Martens Regularity Comparativism 7/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Best Systems Account

Mill-Ramsey-Lewis

Popular way of cashing out the exact way in which the laws supervene on the mosaic Laws are theorems of the ‘best’ axiomatisations of the Humean mosaic best = ‘simplest’ + ‘strongest’

(Lewis, 1973; Earman, 1984)

Niels Martens Regularity Comparativism 8/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Regularity Relationalism

Response to i.a. Newton’s bucket (i.e. inertial effects) Core Idea: It is merely the truth of Newton’s laws in certain frames that privileges those frames, not the structure of absolute space. (Van Fraassen, 1970) Regularity Approach: Consider all possible reference frames that are naturally adapted to the mosaic: only in some frames will the best axiomatisations be Newton’s laws. Claim: those are the best laws overall. → Inertial frames & laws supervene as a package deal.

(Hugget, 2006)

Niels Martens Regularity Comparativism 9/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Comparativism

Comparativism: Denial of absolutism: quantity ratios are not grounded in intrinsic quantities Case study: mass Motivation: Ontological parsimony: throw away intrinsic masses Challenge: comparativism’s bucket

Niels Martens Regularity Comparativism 10/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Comparativism’s bucket

Fg = G mM

r2

ve =

• 2GM

r

v0 v0 F F

Double Mass

v0 v0 F F

(Baker, manuscripts; NCMM, manuscripts)

Niels Martens Regularity Comparativism 11/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Regularity Comparativism I

Absolutism-Comparativism debate concerns the relative fundamentality of intrinsic mass and mass ratios, but is ofen equivocated with the debate about the empirical meaningfulness of mass. Wiggle room: accept that the comparativism’s bucket argument proves that intrinsic mass is empirically meaningful, but insist that that can be accounted for without grounding mass ratios in intrinsic masses. Use the regularity approach

Niels Martens Regularity Comparativism 12/25

The Regularity Approach Responses Empiricism about laws of nature Regularity Relationalism Regularity Comparativism

Regularity Comparativism II

Core idea: Absolute mass scale is privileged because of the truth of Newton’s laws (incl. Gravitational Law) for that choice

• f scale, not because that scale is grounded in absolute masses.

Liberalisation: Replace the absolutist Humean mosaic by a mosaic consisting of fundamental mass ratios. Ontological ‘coordinates’: Consider all possible choices of an absolute mass scale. Regularity Approach: Claim: Only for one choice of the absolute mass scale will the laws be the best axiomatisation, and those laws are Newton’s laws & the Gravitational Law. → Mass scale & laws supervene as a package deal.

Niels Martens Regularity Comparativism 13/25

Outline

1

The Regularity Approach

2

Responses

The Regularity Approach Responses It doesn’t work Separability Eliminativism

It doesn’t work

A disanalogy with regularity relationalism?

For any choice of mass scale, equally simple laws can be found, simply by adjusting the value of Newton’s Constant. Regularity relationalism:

L(co) = LNG(co) + Lcorr(co) L(cbs) = LNG(cbs) L(cbs) are the best laws overall

Regularity comparativism:

LNG(c′

• (G)) + Lcorr(c′
• ) = LNG(c′
• (G′)): as ‘good’ as LNG(c′

bs(G))

No unique mass scale picked out by regularity approach

Does not mater. All pairs of scale & law that are picked out are equally fine. cf. several inertial frames

Niels Martens Regularity Comparativism 15/25

The Regularity Approach Responses It doesn’t work Separability Eliminativism

Separability

Comparativism violates Separability Liberalise/Generalise Separability, or give it up altogether

Niels Martens Regularity Comparativism 16/25

The Regularity Approach Responses It doesn’t work Separability Eliminativism

Generalising Separability

Analogous quantum debate Give up on 4D-fundamentalism Generalised Separability (GS): quantify over points in configuration space instead (Albert, 1996) Why care about GS? Or Separability? Albert, Lewis, Einstein: classical world is manifestly separable

(Maudlin, 2007)

Inductive argument Why would this motivate GS? If GS, Separability is still violated.

Niels Martens Regularity Comparativism 17/25

The Regularity Approach Responses It doesn’t work Separability Eliminativism

Giving up on separability

Separability & Supervenience are logically independent, but can Supervenience be motivated independently from Separability?

“

Humean supervenience is named in honor of the greater [sic] denier of necessary connections.

Lewis, 1986”

Niels Martens Regularity Comparativism 18/25

The Regularity Approach Responses It doesn’t work Separability Eliminativism

Giving up on separability

Separability & Supervenience are logically independent, but can Supervenience be motivated independently from Separability? Humean Empiricism: dislike of necessary connections

“

Prima facie, the kind of world that violates Separability is one in which there are necessary connections between distinct ex- istents: that is, in which there are fundamental and irreducible relations between pointlike things.

Dewar, manuscript”

Niels Martens Regularity Comparativism 18/25

The Regularity Approach Responses It doesn’t work Separability Eliminativism

Giving up on separability

Separability & Supervenience are logically independent, but can Supervenience be motivated independently from Separability? Humean Empiricism: dislike of necessary connections

• > motivates Humean Supervenience as a package deal

Ontological parsimony (Hugget, 2006)

Not clear that non-separable mosaics are more parsimonious Not clear that Supervenience is more parsimonious than Governing Law This motivation leads to Eliminativism

Niels Martens Regularity Comparativism 18/25

The Regularity Approach Responses It doesn’t work Separability Eliminativism

Non-ad-hoc criterion & Eliminativism

Why stop at reducing intrinsic masses? Why not eliminate mass altogether (i.e. give up Qantity Primitivism)? Regularity Eliminativism (Hall, manuscript)

Ontologically parsimonious No motivation for Qantity Primitivism anyway Removes problems with mass & charge swapping (Esfeld)

Non-ad-hoc criterion needed to block further reduction (Pooley,

2013)

Not a problem for regularity relationalism (pace Pooley) Problem for comparativism: throwing away the massive baby with the bath water “Transcendental” argument

Narlikar, 1939

Niels Martens Regularity Comparativism 19/25

The Regularity Approach Responses It doesn’t work Separability Eliminativism

Non-ad-hoc criterion & Eliminativism

Niels Martens Regularity Comparativism 19/25

Conclusion

1

RC uses the Mill-Ramsey-Lewis Best Systems Account in an atempt to have the absolute mass scale supervene on a comparativist mosaic together with the laws of Newtonian Gravity as a package deal.

2

Although the regularity approach does not in fact succeed in picking out a unique absolute mass scale, all of the ‘mass scale + law’ pairs that it picks out are equally fine.

3

RC is manifestly non-separable. Humean Empiricists cannot give up Separability without losing Supervenience as well. Ontological parsimony might provide an independent motivation for Supervenience.

4

The regularity approach favours regularity eliminativism over regularity comparativism, which is fatal for comparativism.

References

D.Z. Albert (1996), ‘Elementary Qantum Metaphysics’, in J.T. Cushing et al. (eds.) Bohmian Mechanics and Qantum Theory: An Apraisal, 277-284, Kluwer Academic Publishers D.J. Baker, ‘Some Consequences of Physics for the Comparative Metaphysics of Qantity’, Manuscript

• N. Dewar (2015), ‘What the Humean cannot say about

entanglement’, manuscript

• J. Earman (1984), ‘Laws of Nature: The Empiricist Challenge’, in

D.M. Armstrong, R. Bogdan (ed.), Profiles, Vol.4, Dordrecht:

• D. Reidel Publishing Company.
• N. Hall, ‘Humean Reductionism About Laws of Nature’,

Manuscript

References - continued

• N. Hugget (2006), ‘The Regularity Account of Relational

Spacetime’, Mind 115:457

• D. Lewis (1973), Counterfactuals, Cambridge, MA: Harvard

University Press

• D. Lewis (1986), Philosophical Papers, Vol. ii, Oxford: OUP

N.C.M. Martens, Transfer & Confirmation of Status Dissertations, Oxford University, Manuscripts

• T. Maudlin (2007), ‘Why Be Humean?’, in The Metaphysics

Within Physics, Clarendon Press (UK)

References - continued

• T. Maudlin (2007b), ‘The Whole Ball of Wax’, in The Metaphysics

Within Physics, Clarendon Press (UK) V.V. Narlikar (1939), ‘The Concept and Determination of Mass in Newtonian Mechanics’, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Series 7, 27(180):33-6

• O. Pooley (2013), ‘Substantivalist and Relationalist Approaches

to Spacetime’, in R. Baterman (ed.) The Oxford Handbook of Philosophy of Physics, Oxford: OUP B.C. Van Fraassen (1970), An Introduction to the Philosophy of Time and Space, New York: Columbia University Press

Extra Slide: Regularity Relationalism in more detail

Leibnizian-Humean mosaic: Leibnizian spatial relations of the particles over time & their fundamental intrinsic properties such as mass and charge. Ontological coordinate frames:

Adapted frame: adapted to a reference body if that body is at rest at the origin of the frame Adapted frames + all frames related to those adapted frames by arbitrary continuous spatially rigid transformations

Best System Coordinates: Subset of ontological coordinate frames which correspond to the axiomatisations that are best

• verall (i.e. Newton’s laws). That is, the inertial frames.

Extra slide: Explanatory Circularity

Should we be surprised that the regularity approach retrieves the correct laws and mass scale? No! Puting the cart before the horse Trajectories are explanandum, not explanans Generic problem of Humean Supervenience (Maudlin, 2007b)