The Problems of Essentialist Natural Necessity

How absolute are the laws anyway?

The Puzzle of Laws and The Appeal of Natural Necessity

There is a divide in the essentialist-dispositionalist literature regarding natural (or physical) necessity: whereas some authors¹ take natural necessity to be a mere species of metaphysical necessity – they are “necessitarians” about laws of nature – others² take natural necessity to be distinct from metaphysical necessity – they are “contingentist” about laws of nature, that is, they take them as exemplars of a softer or weaker type of necessity that grants them some form of contingency.

The latter authors’ use of the term “natural necessity” is mainly motivated by an attempt at accommodating two antithetical intuitions which seem to pervade our thought regarding the laws of nature. As John T. Roberts has put it, “laws of nature resemble necessary truths in some respects, but they resemble contingent truths in others”³. Whereas “they resemble necessary truths by being extremely resilient under counterfactual suppositions: for the most part, however differently things might have gone, we tend to assume that the laws of nature would still have held”, they “resemble contingent truths in that we seem to have no trouble imagining, conceiving of, and even solving physics problems about situations in which nature is governed by a different set of laws, and the actual laws of nature are false”⁴. These two intuitions create a puzzle: whereas, on the one hand, one wants to preserve the seeming metaphysical contingency of laws, there also seems to be something necessary to them.

By positing natural necessity as distinct from metaphysical necessity, some essentialists try to have their cake and eat it too. That is, they try to maintain all the advantages that come from having a necessitarian view of natural necessity without letting go of laws’ seeming contingency.

I shall argue that, at least if one accepts a broadly essentialist-dispositionalist picture of laws, that is not possible. That is, essentialism requires necessitarianism, and in trying to preserve one without the other, one will only fall into the problems that essentialism was meant to solve in the first place.

Nevertheless, within a broadly general essentialist-dispositionalist picture of nature, contingency is still preserved at the appropriate level, rendering necessitarianism about laws unproblematic. By grounding laws in the essences of natural kinds, essentialism helps us stress that metaphysical principles – such as the essences of substances – are more fundamental than the natural laws studied by physical science, ultimately grounding them and elucidating the necessary structures that make those natural regularities possible.

A Clarification on Necessitarianism

E. J. Lowe is one of the representatives of the “contingentist” side of the debate. While accepting a broadly essentialist-dispositionalist account of laws, Lowe rejects the thesis that the laws of nature are necessary. He argues that there is natural necessity and “it is only a species of relative necessity. To say that a state of affairs is “naturally necessary” is merely to say that it is a state of affairs which must be the case given the laws of nature”⁵.

One of the reasons Lowe rejects the metaphysical necessity of laws of nature is that it seems to entail that they are true in all possible worlds, whereas “many philosophers have strong intuitions that natural laws are not necessary in the strongest possible sense—that a natural law which obtains in this, the actual world, need not obtain in every possible world”⁶. However, it should be clear that the essentialist-necessitarians don’t need to hold that the laws of nature are true in every possible world.

There are two possible ways of interpreting the necessity of laws. The strong interpretation is Lowe’s: a law of nature, such as “salt dissolves in water”, is true in every possible world, even those with no salt or water.

But what essentialist necessitarians usually mean by the necessity of laws is weaker: they hold that a law such as “salt dissolves in water” is true in every possible world in which the law’s referring expressions are not empty. That is, that law of nature is only true if salt and water exist in that world. With that said, one could indeed imagine worlds in which something very similar to salt does not dissolve in something very similar to water. But, according to the essentialist, they would be neither salt nor water.

Lowe’s Circularity Problem

Having clarified the essentialist-necessitarian thesis, we can investigate Lowe’s essentialist-contingentist account of natural necessity.

One of the greatest problems that any defender of natural necessity has to face is the circularity problem. This problem arises from the fact that any attempt at defining natural necessity has to limit the worlds one assesses to the ones with the “same basic nature as our world”⁷.

But as John Foster puts it,

“if we make it a requirement of a world's sharing the basic nature of our world that it should share its nomological organization, then, of course […], the law-sustained regularities in our world will extend to all worlds in the relevant range. But this will be so in a way that is wholly trivial and of no help in illuminating the sense in which the regularities are necessary”⁸.

Lowe recognizes this problem:

“one cannot non-circularly explain this notion of necessity in terms of truth in all worlds in which the actual laws of nature obtain, if one appeals to the very notion of necessity in question in explaining what constitutes a law”⁹.

Lowe avoids the problem by grounding laws in natural kinds. This provides him with an independent account of the necessity of the laws themselves and thus enables him to escape the vicious circle of natural necessity. However, it is not clear that he can do this whilst maintaining that natural necessity is distinct from metaphysical necessity.

All natural kinds or essentialist theorists, Lowe included, agree that laws of nature are grounded in the essences of properties and, as such, they are the source of their necessity (be it natural or metaphysical).

This happens because, “If Fs have essential natures then they must behave in certain ways, so long as Fs exist. The descriptions of their behaviour must be true, so long as the description concerned entails that Fs exist”¹⁰. But this seems to entail metaphysical necessity, not Lowe’s natural necessity. There will be no world in which Fs exist but the laws that characterize their behaviour do not obtain.

As Bigelow Ellis and Lierse put it, if “we explain the necessity of laws in terms of the essential properties of natural kinds [… it is not] possible for a natural kind to have different essential properties from those it does in fact possess - if one of its properties could be absent, it would not be an essential property”¹¹. Thus, whatever is true in virtue of the essential properties of a natural kind or substance must hold whenever that natural kind or substance exists.

As such, Lowe’s solution to the circularity problems seems to entail a form of necessitarianism, not of natural necessity as he understands it. So how does Lowe get to natural necessity as a solution to the circularity problem?

Whereas the necessitarian argues that the laws governing Fs will obtain insofar as Fs exist, Lowe holds that a “law L for Fs might be true in w1 and false in w2 even though Fs exist in both worlds”¹². In this sense, laws would indeed be contingent, even if naturally necessary. As such, Lowe believes “that water—that very substance—could, very arguably, exist in a possible world in which there was not a natural law that water dissolves common salt”¹³. How so? According to Lowe, it is not part of the essence of water that it dissolves salt. As he puts it:

“it is part of the essence of water that it consists of hydrogen and oxygen atoms in the ratio of two to one; but the point is that I consider that the laws governing hydrogen and oxygen atoms are quite conceivably different in different possible worlds—that these laws are not metaphysically necessary states of affairs, but merely contingent ones).”¹⁴

Setting aside Bird’s argument for the necessity of salt dissolving in water¹⁵ (and Lowe’s not-that-convincing response to it¹⁶), there seems to be a deeper trouble, noted by Oderberg¹⁷, in Lowe’s general reasoning.

Lowe argues that just as it “is part of the essence of water that it consists of hydrogen and oxygen atoms in the ratio of two to one”, the essence of an electron is to be negatively charged. Lowe even considers these to be, in a sense, metaphysically necessary laws of nature since both water and electrons are partially defined that way (H2O and negatively charged, respectively). As Armstrong has noted,¹⁸ it is questionable whether these “composition laws” are genuine laws of nature.

Either way, they are certainly taken, in Lowe’s ontology, to be real definitions and, as such, metaphysically necessary laws. At the same time, he takes salt dissolving in water to be a contingent truth. This creates a problem as “Lowe appears to adhere to a ‘governing’ conception of the contingent natural laws, according to which they determine kinds of object to behave in certain ways, but where the kinds themselves are ontologically independent of those laws in the sense that the identity of those kinds does not depend on the laws in which they figure”¹⁹.

But in embracing a governing conception of the contingent natural laws, Lowe’s theory of laws of nature ends up falling into the problems of other accounts (such as DTA) that essentialism was supposed to deal with in the first place.

One of the most attractive features of essentialist-dispositionalist accounts of laws is their capacity of explaining what, in DTA accounts, is left unexplained: the necessary character of laws. They do this by making that necessity relation immanent to natural kinds. As such, laws do not govern kinds but rather flow, emerge or supervene (as one prefers) from them.

On the immanentist picture, to which essentialists subscribe, “what ‘ties’ kinds to attributes in a law-like way is part of the very essence of those kinds, without which tie those kinds would be something other than what they are”²⁰. But if one unknots that tie, one will have to give another explanation for that governing relation. And what exactly is doing the governing? A universal, a relation between universals, a platonic form?

We go back to the great problem with the DTA account. A law of nature may indeed be an irreducible dyadic relation of necessitation holding between universals. But what explains that relation of necessity between universals? As Bigelow et al., echoing the witty David Lewis, put it: “labelling the relevant relation a 'necessitation relation' cannot by itself create a necessary link between the related things, any more than calling someone 'Armstrong' can give them mighty biceps”²¹. After all, universals – or any other abstract object – are causally inert.

The essentialist deals with this problem by grounding that same nomic necessitation relation in the essences of things. Instead of being ultimately analyzable or primitive, that relation merely derives from the natures of the natural kinds involved in that relation.

In order to preserve the contingent character of natural laws, Lowe creates a hybrid theory that ends up with the problems that his essentialist-dispositionalist account was supposed to deal with. He takes some laws to be metaphysically necessary because they describe immanent facts about kinds. But he takes other laws about those same kinds to be metaphysically contingent and “these contingent laws cannot be immanent to the natures of what they govern [because] if they were, they would not be contingent”²². However, even if he takes these laws to be naturally necessary, Lowe will not be able to non-circularly explain their necessity because they are not immanent to kinds.

Laws Are Not the Place for Contingency

Going back to the puzzle of laws, it does not seem to be possible, as natural necessitarians like Lowe want to, to have the cake and eat it too. We may very well be able to ground and explain the laws of nature, but that will be at the cost of necessitarianism. However, it is not clear that that is a problem, especially if one subscribes to an essentialist ontology (as Lowe does).

According to essentialism, laws of nature are relations between properties that supervene on properties, potencies, causal powers of substances or natural kinds. That is, laws are not ontologically primitive. And if one treats laws as “ontologically derived entities . . . and not as a fundamental category in the ontology”²³, there is still room for contingency, it is just not found at the level of laws.

Laws are contingent in the sense that they concern – or supervene on – objects that are contingent. As such, the world could be otherwise if the natural kinds that populate it were otherwise.

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Bibliography

Armstrong, David. What is a Law of Nature? Cambridge University Press, 1983.

Bigelow, John, Brian Ellis, and Caroline Lierse. "The World as One of a Kind: Natural Necessity and Laws of Nature." The British Journal for the Philosophy of Science 43, no. 3 (1992): 371-388.

Bird, Alexander . "Necessarily, salt dissolves in water." Analysis 61, no. 4 (2001): 267–274 .

Ellis, Brian. Scientific Essentialism. Cambridge University Press, 2001.

Fine, Kit. "Varieties of Necessity." In Conceivability and Possibility, by Tamar Szabo Gendler and John Hawthorne, 253-281. Oxford: Oxford University Press, 2002.

Foster , John . The Divine Lawmaker: Lectures on Induction, Laws of Nature, and the Existence of God. Oxford: Clarendon Press, 2004.

Lowe, E. J. The Four-Category Ontology: A Metaphysical Foundation for Natural Science . Oxford : Oxford University Press , 2005.

Oderberg, David. Real Essentialism. New York: Routledge, 2007.

Oderberg, David. "The Impossibility of Natural Necessity." In Ontology, Modality, and Mind: Themes from the Metaphysics of E. J. Lowe, by Alexander Carruth, Sophie Gibb and John Heil, 73-93. Oxford : Oxford University Press , 2018.

Roberts, John T. . "Some Laws of Nature are Metaphysically Contingent." Australasian Journal of Philosophy 88, no. 3 (2010): 445-457.

Tabaczek, Mariusz. Emergence: Towards A New Metaphysics and Philosophy of Science. Indiana: University of Notre Dame Press, 2019.

1. We will mostly consider: Bigelow, John, Brian Ellis, and Caroline Lierse. "The World as One of a Kind: Natural Necessity and Laws of Nature." The British Journal for the Philosophy of Science 43, no. 3 (1992): 371-38; Bird, Alexander. "Necessarily, salt dissolves in water." Analysis 61, no. 4 (2001): 267–274; Ellis, Brian. Scientific Essentialism. Cambridge University Press, 2001; Oderberg, David. Real Essentialism. New York: Routledge, 2007; Oderberg, David. "The Impossibility of Natural Necessity." In Ontology, Modality, and Mind: Themes from the Metaphysics of E. J. Lowe, by Alexander Carruth, Sophie Gibb and John Heil, 73-93. Oxford: Oxford University Press, 2018.

2. We will mostly consider: Lowe, E. J. The Four-Category Ontology: A Metaphysical Foundation for Natural Science. Oxford: Oxford University Press, 2005; and Fine, Kit. "Varieties of Necessity." In Conceivability and Possibility, by Tamar Szabo Gendler and John Hawthorne, 253-281. Oxford: Oxford University Press, 2002.

3. Roberts, John T. "Some Laws of Nature are Metaphysically Contingent." Australasian Journal of Philosophy 88, no. 3 (2010): 445.

4. Ibid.

5. Lowe, E. J. The Four-Category Ontology: A Metaphysical Foundation for Natural Science, 147–148.

6. Ibid. 142

7. Foster, John. The Divine Lawmaker: Lectures on Induction, Laws of Nature, and the Existence of God (Oxford: Clarendon Press, 2004), 90.

8. Ibid.

9. Lowe, E. J. The Four-Category Ontology: A Metaphysical Foundation for Natural Science, 148.

10. Oderberg, David. The Impossibility of Natural Necessity, 74.

11. Bigelow, John, Brian Ellis, and Caroline Lierse. The World as One of a Kind: Natural Necessity and Laws of Nature, 379.

12. Oderberg, David. The Impossibility of Natural Necessity, 74.

13. Lowe, E. J. The Four-Category Ontology: A Metaphysical Foundation for Natural Science, 132.

14. Ibid.

15. Bird, Alexander. Necessarily, salt dissolves in water.

16. Lowe, E. J. The Four-Category Ontology: A Metaphysical Foundation for Natural Science, 165-166.

17. Oderberg, David. The Impossibility of Natural Necessity, 77-82.

18. Armstrong, David. What is a Law of Nature? (Cambridge University Press, 1983), 138.

19. Oderberg, David. The Impossibility of Natural Necessity, 81.

20. Ibid.

21. In Bigelow, John, Brian Ellis, and Caroline Lierse. The World as One of a Kind: Natural Necessity and Laws of Nature, 377.

22. Oderberg, David. The Impossibility of Natural Necessity, 82.

23. Tabaczek, Mariusz. Emergence: Towards A New Metaphysics and Philosophy of Science (Indiana: University of Notre Dame Press, 2019), 244.