Nomological Necessity and Theism
June 30, 2012 — 20:09

Author: Andrew Moon  Category: Existence of God  Tags: , , , ,   Comments: 25

In Where the Conflict Really Lies, which James Beebe has nicely reviewed, Alvin Plantinga discusses nomological necessity, the necessity had by physical laws. As he (and everybody else) points out, propositions like
2) Every sphere made of gold is less than 1/2 mile in diameter
are true and universal. However, there is a clear sense in which (2) is not necessary in the sense required for lawhood (the sort of necessity we call ‘nomological necessity’). On the other hand, the proposition that no object can increase from a velocity less than the speed of light to a velocity more than the speed of light is nomologically necessary. Also, it does not seem that this proposition is necessary in the broadly logical or metaphysical sense; the law seems contingent.
How are we to understand nomological necessity? Plantinga suggests:

The sense in which the laws of nature are necessary, therefore, is that they are propositions God has established or decreed, and no creature–no finite power, we might say–has the power to act against these propositions, that is, to bring it about that they are false (281).

(Moon’s comment: the second conjunct here seems to be entailed by the first; if God has “established or decreed the proposition”, then no finite power can make it false. So, the second conjunct is technically redundant, but I think it is still informative.) Plantinga goes on to illustrate,

It is as if God says: “Let c, the speed of light, be such that no material object accelerates from a velocity less than c to a velocity greater than c”; no creaturely power is then able to cause a material object to accelerate from a velocity less than c to one greater than c. The laws of nature, therefore, resemble necessary truths in that there is nothing we or other creatures can do to render them false… Though these laws are finitely violable, they are nevertheless contingent, in that it is not necessary, not part of the divine nature, to institute or promulgate just these laws. God could have created the world in such a way that the speed of light should have something quite different from c (281)

Plantinga later writes, while summing up the section,

Third, theism enables us to understand the necessity or inevitableness or inviolability of natural law: this necessity is to be explained and understood in terms of the difference between divine power and the power of finite creature. Again, from the point of view of naturalism, the character of these laws is something of an enigma. What is this alleged necessity that they display, weaker than logical necessity, but necessity nonetheless? (283)

Two questions. First, can anybody think of any problems with Plantinga’s theistic account? Second, I wonder if naturalists do have alternative accounts of nomological necessity. Plantinga does mention/cite how some naturalists have reduced nomological necessity to metaphysical necessity; I wonder if there are naturalists who don’t take this route. This is outside of my area, so I’m curious what other people know.

Comments:
  • Kevin

    Minor nitpick: it is more precise to formulate the example of “speed-limit” as the inviolable magnitude of 4-velocity vectors. Talking about the geometric speed of light without reference to the time dimension doesn’t adequately account for relativistic time dilation.
    While I don’t own a reference work about, and am not particularly conversant with, philosophic accounts of natural law, I do know that the following text is an excellent place to start: http://www.amazon.com/Philosophy-Science-Central-Martin-Curd/dp/0393971759

    July 1, 2012 — 14:09
  • Tg

    A related question: Would it be a theistic account of natural laws that construed them as shared causal powers or relations between universals, or whatever, but then added that God brings about these powers, relations, etc? I suspect that if the view is that the powers, etc, are not so much as intelligible or possible on naturalism, then the account must count as theistic. On the other hand, if the view is that such things are otherwise intelligible or possible, then theism is a little more incidental to the account. (Compare: do theistic botanists with otherwise the same views as atheistic botanists on flowers, have an alternative theistic account of the nature of flowers?)
    So I suspect that if there is something (particularly that governs the behavior of things) that God brings about when he says “such-and-such is a law” and that is intelligible or possible on naturalism, then the account isn’t exactly theistic, and the naturalist could posit that reality, whatever it be, but absent God, as an alternative account. Just my initial thought. But then perhaps I don’t understand Plantinga’s views here properly; I haven’t read the book.
    As for naturalists who do not reduce nomological necessity to metaphysical necessity, I think Armstrong would be an example (at least Armstrong around 1983) as would Lewis. But these views aren’t closely related to their views on naturalism or theism, I think.

    July 1, 2012 — 14:16
  • Andrew Moon

    Kevin,
    Thanks, and as you noted, it is minor; nothing stands or falls on that bit.
    Tg,
    Well, I don’t think Plantinga’s saying that naturalists don’t have an account of laws, but that they don’t have an account of what it is for laws to be necessary. This may also help:

    The philosopher David Armstrong at one time spoke of laws as involving a necessitating relationship among universals: a law is just the expression of a certain necessary relationship between universals. But, as David Lewis pointed out, naming this relation “necessity” doesn’t tell us much.

    Interestingly, after this citing of Armstrong (“What is a Law of Nature?, 1985), Plantinga goes on to say, “Armstrong later decided that the laws of nature are logically necessary after all, prompted no doubt by the difficulty of saying what this other brand of necessity might be” (280). He unfortunately doesn’t give a citation.
    God’s establishing or decreeing some proposition is what it is for that proposition to be necessary; this explains why no finite creature can violate the law (make the proposition false). We cannot make false what God determines to be true. As far as I can tell, this is a uniquely theistic account; I think I didn’t understand you where you seemed to imply that a naturalist could make use of it.

    July 1, 2012 — 21:41
  • Clayton Littlejohn

    So God decrees that every sphere of gold is less than 1 mile in diameter. Infidels try time and time again to make a giant sphere to violate this decree and God strikes them with lightning. Seems to me that (2) isn’t a law, but we have a decree backed by the sort of violence that prevents its violation. Counterexample? That seems to depend upon whether a decree is necessary or sufficient. If intended tobe sufficient, we have a counterexample. If only necessary, I suspect the example just shows hat this “account” is not terribly illuminating.

    July 2, 2012 — 3:22
  • I don’t think that on the theistic account these decrees and backed by any violence. God maintains these physical laws by preserving all of creation according to these “decrees”. So God has set up (or created or established) the physical universe in such a way that the speed of light is the universal speed limit, say.
    As for (2) not being a law, Andrew said as much in the original post when he said, “However, there is a clear sense in which (2) is not necessary in the sense required for lawhood”

    July 2, 2012 — 4:00
  • 1. This seems to make the content of each divine promise into a law of nature. But it doesn’t seem correct to say that it is a law of nature that all those who accept Christ and live according to the Spirit are saved, or that bread and wine changes into Christ’s body and blood at Mass, or that the Pope does not err in ex cathedra pronouncements.
    2. Moon: ‘the second conjunct here seems to be entailed by the first; if God has “established or decreed the proposition”, then no finite power can make it false. So, the second conjunct is technically redundant, but I think it is still informative.’ Actually, given Plantinga’s Molinism, you do need the second conjunct. Given Molinism, we can say that God established or decreed the proposition that David would freely accept the kingship of Israel. He did this by noting that the conditionals of free will are such that if David is put in certain circumstances, he will accept the kingship, and then deliberately putting David in those circumstances so that he might accept the kingship. But it is not a law of nature that David would freely accept the kingship, and David had the power to refuse. Similarly on Calvinism or Thomism we can say that God can cause someone to freely do something, in such a way that in some important sense the person could have acted otherwise.
    3. So it’s important to Plantinga’s view that both conjuncts be there. I wonder how explicitly on Plantinga’s view God has to will that no creature should have such-and-such a power. Suppose God chooses to create no creature. Then is he implicitly willing that no creature should have a power to make a cake, because there not being any creature entails that no creature has the power to make a cake? If so, then in a world where there is nothing but God, it is a law of nature that there are no cakes. And that doesn’t seem right. So it’s not enough that God should will something that entails that no creature can do something to make a law. So God has to explicitly will that no creature be able to do it. But now what evidence do we actually have that God explicitly willed, say, that no creature have the power to make something go faster than light?
    4. Couldn’t an angel do something contrary to a law of nature? If so, the account fails, since angels are creatures.
    5. A minor tweak is needed. Plausibly, anything that’s metaphysically necessary, say that 2+2=4 or that God exists, is also nomologically necessary. But God surely doesn’t decree that God exist or that no creature should have the power to make 2+2 not be 4. So the account needs to be extended. Maybe the things that God decrees in the way Plantinga describes should count as primitively nomologically necessary, and then anything that follows of metaphysical necessity from primitively nomologically necessary propositions counts as nomologically necessary.

    July 2, 2012 — 9:27
  • Andrew Moon

    Hi Roland,
    Thanks for the note. I think that Clayton was saying that in his supposed/alternate scenario (where God strikes down infidels, (2) would still not be a law. But according to Plantinga’s account, it’s supposed to be.
    Clayton and Alex,
    Very nice comments. I wouldn’t’ve thought of those on my own (or at least it would have taken me longer). I’ll think about them, and if I have anything else to say, I’ll post a comment.

    July 2, 2012 — 10:33
  • Andrew Moon

    Clayton and Alex,
    Note that Plantinga’s not giving an account of lawhood, but an account of the necessity of lawhood; given that p is a law, what is it for that law to be necessary? His account answers that. So, I don’t think Plantinga’s committed to saying that (2) (in Clayton’s scenario) is a law of nature or that each divine promise is a law of nature (as Alex mentions). I’ll have to think about the other comments some more.
    -Andrew

    July 2, 2012 — 12:02
  • Tg

    I don’t know whether this would answer your question, but you might try looking at Marc Lange’s paper , ‘Laws and Their Stability’. John Roberts has a paper, ‘Some Laws of Nature are Metaphysically Contingent’, trying to show that even on scientific essentialism there are some contingent laws. That account could secure necessary laws as well as contingent laws. And I take it that that the accounts are pretty consistent with theism as well as naturalism.

    July 2, 2012 — 12:53
  • Mike Almeida

    I find Plantinga’s claims here puzzling. Why would we need an account of the necessity of natural laws? Laws are exceptionless regularities by definition. The reason no finite creature can violate a law of nature is that, divine decree or not, were one to do so, it would not be a law. So the necessity of these laws is a property of laws whether you’re a necessitarian about natural laws or a regularity theorist or anything in between. It’s not a contingent feature of laws that they disallow violation by finite beings (or anyone else). So what is he explaining? Further, the ‘necessity’ of natural laws that issues from God’s decree is no less consistent with there being the sorts of “law violation” by finite beings needed to preserve freedom in deterministic worlds. If you happen to be an old fashioned compatibilist (a lewis style compatibilist, say) you will argue that same way and no less effectively. If L is a natural law of w, and given L it is determined that finite being S does A in w, S can (is able to, has the power to or whatev) do other than A. But S’s doing so occurs in w’ (not w) and L is “violated” in w’ (not w). In short, S can act in such a way that (as we all know) were S to do so, L would not be a law. So there is nothing about divinely decreed laws that makes the familiar old fashioned compatibilist position any less tenable (NB: I’m not claiming it is (or isn’t) tenable or that anyone should (or should not) be an o.f. compatibilist). Divine decrees don’t make it any less possible to “violate laws” in the way needed to preserve o.f. compatibilism. So, whether you are a regularity theorist or a Plantingan theorist about laws, the way in which they are inviolable is the same, and the way in which they are “violable” is the same.

    July 2, 2012 — 14:49
  • Heath White

    I am actually quite friendly to Plantinga’s view, but I can see someone objecting to it as ad hoc or non-explanatory. Consider that there are laws of physics, laws of chemistry, laws of biology, etc., and corresponding senses of physical necessity, chemical necessity, biological necessity, etc. We might ask what differentiates these necessities. One answer would be polytheistic: there is a physics god whose decrees constitute physical necessity, a chemistry god whose decrees constitute chemical necessity, a biology god etc. etc.
    A pretty good reply to this suggestion is that such a polytheist is just making things up. I think the atheist would be tempted in the same direction toward Plantinga’s suggestion. My thought is that Plantinga’s suggestion might be taken seriously after you already have some reason to believe in a God, but not as free-standing evidence in its own right.

    July 2, 2012 — 19:13
  • Andrew Moon

    Heath,
    Just to be clear, Plantinga is not trying to make an inference to the best explanation, arguing that God is the best explanation of the necessity of laws. Instead, he is trying to show, in this chapter, a concord between theism and some aspect of science (the necessity of laws).

    July 2, 2012 — 22:46
  • Andrew
    Ah I see. Apologies to Clayton… I misread.

    July 3, 2012 — 1:24
  • Clayton Littlejohn

    Another gripe. It is common for people to say that laws support counterfactuals in ways that accidental generalizations do not. If you are a necessitarian about laws, it is easy to see how this is supposed to work. It is tricky to see how you could do this without necessitarianism, but people have tried it using contingent relations between universals. I can see why someone might be skeptical of any attempt to explain how a law could support a cf without any appeal to necessitarianism about laws, but surely there would be something deeply disappointing about a proposed solution that simply invokes the deity. So, how does P pull it off? If he accepts the necessitarian view, God would be otiose. If he rejects the necessitarian view, what arehis grounds for doing so? How does God help explain how a law supports a cf (e.g.,if this metal had been heated, it would expand?)

    July 3, 2012 — 3:23
  • Clayton Littlejohn

    Quick addition. This follows up on Tg’s post.
    On P’s view, what is God supposed to have done in establishing a law? There’s the decree and then there’s everything subsequent to it. Should we think of the law as something established as a _consequence_ of the decree or is P’s view that the law includes the decree itself? If the former, then it isn’t clear why the naturalist cannot take on board P’s view of what a law is. Maybe P means the latter. Then it’s clear why the naturalist cannot help herself to P’s view. (It’s also clear that his view isn’t well stated on this reading since he says, “we can think of the necessity of natural law both as a consequence and also as a sort of measure of divine power”.)
    If P means the latter, then it seems that P does indeed have a strange view of laws. I might be wrong about this, but I don’t think P has at any point argued against the necessitarian view of laws and hasn’t argued that there aren’t the necessary relations between universals that those in this camp take laws to be. If there were necessary relations between universals of the sort that the necessitarian thought constituted a law, it seems they would hold independent from any divine decree. What would the decree add? I don’t see that it would add much of anything at all.
    There might be interesting ways of filling in the details to formulate an interesting view (e.g., if P had engaged with Shoemaker), but this section goes by far too quickly.

    July 3, 2012 — 4:42
  • Clayton:
    The support of counterfactuals should follow from nomic necessitation. Suppose we have a true material conditional:
    (a) If A, then B
    such that the whole conditional (a) is more necessary than the negation of the antecedent A. Then I think we can conclude:
    (a) Were it that A, it would be that B.
    I am thinking here something like: Paradigmatic empirical claims (e.g., I am sitting now) are less necessary (indeed, not necessary at all) than nomic claims and paradigmatic nomic claims (e.g., massive objects attract) are less necessary than metaphysically necessary claims.
    Being entailed by the decrees of God is then a grade of necessity, and hence when a material conditional follows from the decrees of God, but the negation of its antecedent does not (and does not have some other, stronger kind of necessity either), the corresponding subjunctive conditional also goes.
    The only problem with this version is that in a two-sided deterministic universe it yields backwards conditions. But that conclusion has been defended by Bennett and isn’t a knock-down argument against the position, especially since determinism is in fact false.
    By the way, my principle of when one can go from a material conditional to a subjunctive conditional can also yield non-trivial per impossibile counterfactuals whenever we have a grade of necessity stronger than metaphysical necessity. E.g., definitional necessity, or first order provability.

    July 3, 2012 — 8:26
  • Mike Almeida

    It is common for people to say that laws support counterfactuals in ways that accidental generalizations do not. If you are a necessitarian about laws, it is easy to see how this is supposed to work. It is tricky to see how you could do this without necessitarianism
    I’m (still) not sure what this has to do with necessitariansim. Regularity theorists might just as easily say the same thing,viz. that laws support counterfactuals. All you need for that claim to be true–at least on the recieved views of counterfactuals–is that worlds in which laws (whatever the correct metaphysics happens to be) are broken are typically very distant worlds. Laws weigh heavily in assessing similarity. Regularity theorists agree with this, of course. But what basis could a regularity theorist have for making such a claim? They have the same basis for such a claim as anyone else does: we look at the way counterfactuals are in fact evaluated and we discover that we laws typically matter a lot to similarity. There is no way in which the metaphysics of laws figures into the assessment of these counterfactuals. Not that I can see anyway.

    July 3, 2012 — 10:32
  • Mike Almeida

    Plantinga’s claim above also has nothing to do, that I can tell, with the metaphysics of laws.
    The sense in which the laws of nature are necessary, therefore, is that they are propositions God has established or decreed, and no creature–no finite power, we might say–has the power to act against these propositions, that is, to bring it about that they are false
    The fact that no creature–no finite power, we might say–has the power to act against these propositions, that is, to bring it about that they are false has to do with the fact that they are laws. It has nothing to do with the metaphysics of laws.
    Just an incidental note: I know what it means to say that a law is inviolable. But I have no idea what it means to say that a law is necessary in some ‘weaker sense’ than metaphysically necessary. For instance, that a proposition P (which is a law in W) also holds in 25 other worlds does not make it true that P is necessary in any sense (weak or strong) that I can think of. It’s a contingent proposition.

    July 3, 2012 — 11:07
  • Mike:
    “I have no idea what it means to say that a law is necessary in some ‘weaker sense’ than metaphysically necessary.”
    Consider claims like: “For a human to survive, it is necessary that she have nutrition, hydration and oxygen.” This is a necessity claim, but it is not a metaphysical necessity claim, since it is metaphysically possible for humans to survive without nutrition, hydration or oxygen. The necessity here is a weaker one than the metaphysical one. Ordinary language includes senses of “necessary” that are weaker than metaphysical necessity. Isn’t that all one needs to make sense of the claim that a law is necessary in some weaker sense?
    On my view, possibility is grounded in the powers of things. Stronger senses of possibility correspond to restricting the powers that can be used in the grounding. Thus, creaturely possibility is possibility grounded in the powers of creatures. Stronger senses of possibility then correspond to weaker senses of necessity.

    July 3, 2012 — 11:50
  • Dianelos Georgoudis

    Alex,
    How do you understand metaphysical possibility? My understanding is that metaphysical possibility refers to possible states of the actual world (whereas logical possibility to any world which does not entail internal contradictions). But this understanding does not comport with your “it is metaphysically possible for humans to survive without nutrition, hydration or oxygen”.

    July 3, 2012 — 14:18
  • Mike Almeida

    On my view, possibility is grounded in the powers of things. Stronger senses of possibility correspond to restricting the powers that can be used in the grounding.
    Alex,
    I asked how it could be that ‘laws’ are necessary in some weaker sense. I still can’t see how. I don’t think the examples you offer are really examples of weak necessities. They are just conditional metaphysical necessities: e.g., Metaphysically necessary [Humans of the sort we find in @ survive only if they have nutrition]. It’s not another special sort of necessity. And that’s good since we shouldn’t be multiplying modalities anyway.
    On the other claim, I’m inclined to agree that possibility is grounded in powers (in some sense), since I’m inclined to deny brute possibilities. Roughly, I’m inclined to deny the distinction between a world being actualizable and a world being possible. For what it’s worth, Plantinga affirms brute possiblities, and maintains that distinction (which has an important role in his FWD). If you think that possibility is grounded in powers, you probably have a nice modal rebuttal to FWD.

    July 3, 2012 — 15:18
  • Mike:
    “I don’t think the examples you offer are really examples of weak necessities. They are just conditional metaphysical necessities”
    Well, that’s one theory of weaker necessities, that they are just conditional metaphysical necessities. I don’t think it’s the correct theory of weaker necessities, though. 🙂
    That’s an interesting objection to the FWD, by the way.

    July 3, 2012 — 19:38
  • Clayton Littlejohn

    “I’m (still) not sure what this has to do with necessitariansim. Regularity theorists might just as easily say the same thing,viz. that laws support counterfactuals. All you need for that claim to be true–at least on the recieved views of counterfactuals–is that worlds in which laws (whatever the correct metaphysics happens to be) are broken are typically very distant worlds.”
    I didn’t want to say that one needs the necessitarian view to understand how the cfs come out as true, only that one desiderata of an adequate account of laws is that there’s a non-cheesy way for the cfs to come out as true. Easy to see how this should work if, say, you endorsed Shoemaker’s view. Not at all clear how this comes out as true on the divine decree account.

    July 4, 2012 — 14:35
  • Clayton:
    Plantinga can still do the same thing about counterfactuals are regularity theorists, but perhaps with a different closeness measure. One way to do that is to take a closeness measure that weighs more explanatorily prior similarities more heavily. Then since the decrees in question are explanatorily very fundamental–they condition more particular decrees as well as particular events–they will get carried over into counterfactual scenarios.
    In my Worlds book, I have suggested that regularity theorists should probably put a greater weight on temporally prior similarity, as Lewis’s non-time-weighted account fails (given Adam Elga‘s counterexamples as well as mine). So all Plantinga has to do is to replace temporal priority with explanatory priority.

    July 5, 2012 — 8:56
  • I don’t know whether this would answer your question, but you might try looking at Marc Lange’s paper , ‘Laws and Their Stability’. John Roberts has a paper, ‘Some Laws of Nature are Metaphysically Contingent’, trying to show that even on scientific essentialism there are some contingent laws.

    October 6, 2012 — 22:57
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