# Messina, J. (2017): Kant's necessitation account of laws and the nature of natures

@Incollection{messina2017,
author = {Messina, James},
title = {Kant’s Necessitation Account of Laws and the Nature of Natures},
booktitle = {Kant and the Laws of Nature},
shorttitle = {Kant’s Necessitation Account of Laws and the Nature of Natures},
editor = {Massimi, Michela and Breitenbach, Angela},
publisher = {Cambridge University Press},
pages = {131-149},
year = {2017},
file = {~/Library/Mobile Documents/iCloud~com~sonnysoftware~bot/Documents/be-library/messina2017_Kant’s_Necessitation_Account_of_Laws_and_the_Nature_of_Natures.pdf},
doi = {},
url = {http://ebooks.cambridge.org/ref/id/CBO9781316389645},
langid = {},
abstract = {},
keywords = {kant; laws; necessity; natures; essence}}


Cool paper with a useful overview of the “necessitation account” of laws of nature, as opposed to either a “best systems interpretation” of Kitcher or the “derivation account” of Friedman.

the so-called Necessitation Account (NA), aspects of which have been defended by Watkins and Kreines. According to Watkins, “laws of nature are nothing other than the laws of the natures of things. That is, the laws of nature that hold in a given world are a function of the natures that are instantiated in that world” (Watkins 2005: 335). Kreines speaks of particular laws obtaining in virtue of the nature of specific kinds of things. | He uses the example of the solubility of salt. If indeed it is a law that salt is soluble, this is so because of the nature of the kind salt (Kreines 2009: 531–532). Anything with this nature will necessarily be disposed to dissolve in water. (136-37)

Messina initially suggests that NA is naturally read as a “bottom-up” account of natural laws. The difference between bottom-up and top-down accounts is that for bottom-up accounts “laws supervene on the natures and/or essential properties of objects” while for top-down accounts

Historically, top-down models of laws invoked God as a legislator, identifying laws of nature with features of God’s will, such as divine general volitions on the Occasionalist position. Contemporary top-down models of laws invoke universals that stand in sui generis necessitating relations to each other, relations that vary from possible world to possible world, resulting in corresponding changes to the laws. (137)

James is a bit wishy-washy on what his exact view is. He says that his view advocates a bottom-up approach at several points (e.g. 141, 145, 147). But really his view is a kind of “no-priority” or coeval approach where

Kant holds that natures cannot exist apart from their associated laws, and those laws cannot exist apart from (must be realized within) their associated natures. (147)

So - I think James is right that natures cannot exist without correlative laws, but wrong to think that natures are coeval with laws. Stating exactly why is tricky. But James’s view really makes best sense as a kind of no-priority view. I think there is priority. The natures are prior to the laws. They ground the laws. But it is also true that whenever nature N exists so does law L. Laws supervene on natures, and natures ground laws. Natures and laws are ontologically coeval – one cannot exist without the other. But natures grounds laws – it is because the nature is the way that it is that we have the relevant law and not vice versa.

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