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February 27

Metaphysical necessity and the laws of nature

Just wondering: how common are philosophers (and scientists) who believe that the laws of nature are metaphysically necessary? Who are the specific people who support this view, and what arguments do they make? For the purposes of this question, I will especially focus on a strong view in which our world could not have had different laws or natural properties than it actually does/there are no metaphysically possible worlds with different laws or natural properties. This came up while I was reading Chalmers' paper "Does Conceivability Entail Possibility?" in which he claimed that such a position had no good reasons to support it and that philosophers such as Fine and Sidelle (who believed in a weaker notion of necessity themselves) dismissed it. I then read the Stanford Encyclopedia article on "Laws of Nature," which had a section of necessity, and mentioned Shoemaker, Swoyer, Fales, and Bird as supporters of the view that all laws are necessary truths.

The Stanford Encyclopedia article only mentioned those who took a certain dispositional essentialist view, "according to which dispositions have their casual powers necessarily." However, I found some people who might have a similar conclusion while coming at it from a different set of arguments. Alfie Collins, in https://www.academia.edu/34473191/Are_the_Laws_of_Nature_Metaphysically_Necessary , makes a case for metaphysical necessity on different grounds (that arguments against it are weak, that it removes the need for fundamental physical laws to have an explanation, and that it removes the need to assign probabilities to which of different physical laws would actually be true). He specifically criticized some of Chalmers' arguments as well. I also remember reading a book from Google Books in which someone took a necessitarian view, but unfortunately, I can't find out much about it. I don't remember much about it, including the author (even whether that author was a previously mentioned person or not) or the main positive arguments he gave for the necessitarian view. What I do remember is that he criticized the Twin Earth thought experiment and suggested evolutionary reasons why conceivability may not be a good guide to possibility. I don't remember finding or reading any others who took a necessitarian position, although I may just not have searched hard enough.

This is pretty long; I'm asking this because I'm thinking about expanding an article (or perhaps even creating a new one) about this topic, as several important philosophers seem to have weighed in on it. (I'm personally interested as well). I want to find the main sources and arguments necessary to write about this topic, and don't want to miss out on anything. Finding out how prominent and mainstream this view is will be good, so it can be explained according to NPOV, specifically the parts about reporting on views in proportion to their prominence among reliable sources. Diamond Blizzard talk 18:38, 27 February 2019 (UTC)[reply]

Which is the article you want to expand? (Just curious.) I looked at what other encyclopedias are saying in overviews and the two top hits both suggest this is a major topic.

Internet Encyclopedia of Philosophy says one of "two competing theories of Laws of Nature...is the Necessitarian Theory: Laws of Nature are the "principles" which govern the natural phenomena of the world." So your area is one of two main areas of interest per this source.
Stanford Encyclopedia of Philosophy says "Besides the basic question [(What is it to be a natural law?)], the recent literature has also focused on (i) whether laws supervene on matters of fact, (ii) the role laws play in the problem of induction, (iii) whether laws involve metaphysical necessity, and (iv) the role of laws in physics and how that contrasts with the role of laws in the special sciences." So your area is one of five main areas of interest per this source. You'll also get a bunch of references listed in the Necessity section. 70.67.193.176 (talk) 19:04, 27 February 2019 (UTC)[reply]

I'm thinking about which article to expand. Some candidates are Scientific law, Modal logic, or Contingency (philosophy). Or, as I said, it could possibly be a good idea to create a new article about this topic. As for the sources you mentioned:

The Internet Encyclopedia of Philosophy article does not seem to be about the sort of necessity I am talking about - it is, instead, whether the laws of nature are principles that compel things in our world or not, not whether there could be different laws of nature in other possible worlds or not.

The Stanford Encyclopedia of Philosophy article is one I already read and mentioned. Diamond Blizzard talk 19:16, 27 February 2019 (UTC)[reply]

Sorry for missing that you'd mentioned Stanford; I checked for links in your question and missed the plain text reference. I hope you find what you need. 70.67.193.176 (talk) 22:13, 28 February 2019 (UTC)[reply]

Physicists have been debating the Anthropic principle. I'm not sure what would count as evidence for or against metaphysical necessity... AnonMoos (talk) 00:39, 28 February 2019 (UTC)[reply]

It depends on what is meant by the "metaphysical necessity of natural laws". If one means "the necessity that nature has the laws that it has now", then that is the anthropic principle. If one means "the necessity that nature has laws of some sort, in an arbitrary sense, without any particular set of laws being correct, just that it has some absolute laws", that's a different question. --Jayron 32 00:42, 28 February 2019 (UTC)[reply]

@AnonMoos and Jayron32: I'm talking about whether it is necessary that our world has its specific set of laws. I'm also not talking about the anthropic principle, either. Proponents of the anthropic explanation generally believe that other universes could (or even do) have different laws of physics, just that those laws cannot support life/observers. The philosophical view I am discussing says that there could be no other universes/worlds with different laws of nature in the first place at all, and I have written the arguments of some of its supporters above. It should be noted that the arguments for the latter position often depend more on general principles and rational arguments then empirical evidence (even if they support a posteriori necessities and that scientists need empirical evidence to determine what the specific laws of nature are).

Also, just to make it clear, I am not looking for other Wikipedia editors' personal viewpoints or arguments (unless the editor happens to be a notable person). I am looking for more sources than what I have already found (if there are more supporters) and a summary of notable views, which will help me write about this topic on Wikipedia. I suppose that significant counterarguments against this position will also be important to find. This is a philosophical argument, and I do not expect it to be completely settled anytime soon. Diamond Blizzard talk 02:00, 28 February 2019 (UTC)[reply]

I don't believe that I gave any opinion on the matter; I asked a clarifying question so I could better work at helping find you references. --Jayron 32 11:33, 28 February 2019 (UTC)[reply]

Look into Max Tegmark's "mathematical universe hypothesis",[1] which is imho silly, but it's aimed at your question, I would say. 173.228.123.166 (talk) 05:42, 28 February 2019 (UTC)[reply]

I've heard about that hypothesis before, 173.228.123.166. To me, at least, it seems to be the opposite of the position that I was originally discussing - the MUH essentially says that all mathematically coherent universes are not only possible, but do actually exist. Necessitarianism about the laws of nature states, in contrast, that some logically/mathematically coherent universes do not and cannot exist, if they have different laws of nature from our own. I was looking for counterarguments as well, and that counts as one. However, as the MUH is an extreme minority view and I do not remember seeing any dialogue between its supporters and the necessitarians I just mentioned, I do not think it would really be worth mentioning in what I am thinking to write.

It seems that no respondents really understand what the view I am talking about entails. I am not trying to offend anyone here, it is probably just that it is a minority philosophical view that relatively few people actually think about unless they are philosophers. (BTW, I do not believe in necessitarianism myself. It is just that this view has been discussed by a number of prominent philosophers, so I suspect it could be notable and deserve to be written about on Wikipedia).

My TL;DR summary of it: Our laws of nature are metaphysically necessary, not contingent. Even if other sets of laws of nature are logically possible (as in noncontradictory), they could never actually exist, even in another world. Different philosophers have different reasons for believing this claim. There are also counterarguments, of course. Diamond Blizzard talk 17:19, 28 February 2019 (UTC)[reply]

@AnonMoos and Jayron32: I just wrote what might be a clearer, TL;DR explanation right above this. I have also previously mentioned how this position is distinct from things such as the anthropic principle or the mathematical universe hypothesis. You might want to see the articles I mentioned in the original question, as they give a decent explanation of this specific position. Diamond Blizzard talk 17:25, 28 February 2019 (UTC)[reply]

I really think you should look closer at the so-called "strong" version of the anthropic principle as espoused by Barrow and Tippler specifically (and not the weaker versions that deal with "fine tuning" of the universe). As I understand Barrow and Tippler, the entire thesis of their work The Anthropic Cosmological Principle is pretty close to what you say; that the universe we exist in is the only possible universe and the set of laws that govern it are the only possible set of laws. The weaker version, Brandon Carter's, is only a restatement of survivorship bias. The Barrow and Tippler "strong" version is essentially what you're saying, that the universe's current set of laws is not one among a possible set of laws, but the only set of laws that could possibly exist. Tippler was highly criticized for his conclusions, I note, but I think they are close to what you're looking for. If not, can you clarify? Can you explain how the Tippler/Barrow universe is different from the one you are looking for? --Jayron 32 17:32, 28 February 2019 (UTC)[reply]

@Jayron32: I don't know that much about Tippler and Barrow, but from what I've read, their argument does seem to be the claim that the only physical laws that could possibly exist at all are ones compatible with life. I believe that yes, this would count as a variant of necessitarianism about the laws of nature. (At least, unless they believed that other laws of nature could also support life, which I don't think they did. I would not agree with such a statement, but I'm just talking about their beliefs). I was previously trying to differentiate necessitarianism from the Weak Anthropic Principle, which is the more common version of the Anthropic Principle. The WAP often states that universes with other laws of physics are possible, but that we could not be in one of them because they could not support life/observers.(Although note that not everybody believes that only our laws of physics could support observers, so in a broader sense, it means that we could only find ourselves in a universe that could support observers). It should also be noted that necessitarians about the laws of physics don't necessarily believe in the Strong Anthropic Principle.

For the ones I listed above, four are dispositional essentialists. They believe that properties, such as mass and charge, have their dispositions necessarily, so, for instance, mass must obey gravity and charge must repel alike and attract not alike. However, not all dispositional essentialists are necessitarians about the laws of nature - after all, perhaps properties such as "schmass" and "scharge," say, could occur in other worlds and have different dispositions, creating essentially the same thing as different physical laws. You would have to believe, in addition, that only properties that exist in our world are metaphysically possible, which only a few support.

Alfie Collins is interesting because he is not a dispositional essentialist, as far as I can tell. His necessitarianism comes from different reasons. He claims that arguments against it are weak, that it removes the necessity of explaining fundamental laws of nature, likely an impossible task, that it similarly removes the necessity of assigning probabilities to different laws of nature obtaining, and that it is easier to use the uncontroversial laws of nature for what is possible and impossible than controversial conceivability. I also previously found a Google Book with a necessitarian author. Unfortunately, I can't find the book again, and I don't remember the author's name (even if he was a previously mentioned philosopher). Perhaps someone here can find it, or any other people who believe in strong necessitarianism, or any notable criticisms, so I can get more sources than I was able to find with various Google searches. Diamond Blizzard talk 17:56, 28 February 2019 (UTC)[reply]

Diamond_Blizzard -- there's no need to keep at-signing me; I pretty much said what I had to say above, you said that you're not interested in personal opinions, and I really don't have opinions or knowledge about the purely philosophical side of things (which is immune from any empirical confirmation or disconfirmation) in any case (though I know something about physics). AnonMoos (talk) 18:30, 1 March 2019 (UTC)[reply]

Sorry about that, I won't ping you from now on. Diamond Blizzard talk 18:57, 1 March 2019 (UTC)[reply]

Diamond Blizzard, maybe one could say the MUH argues the opposite of essentialism. Scott Aaronson gives a friendly but skeptical review of Tegmark's book in his blog post here and then (somewhat) debates Tegmark himself in the comment section, so you might like that post. E.g. he asks "Is there any Level II or IV multiverse hypothesis that says: sure, the mass of electron might be a cosmic accident, with at best an anthropic explanation, but the mass of the Higgs boson is almost certainly not such an accident? Or that the sum or difference of the two masses is not an accident?" which is sort of like your question, if I understand it. 173.228.123.166 (talk) 08:18, 3 March 2019 (UTC)[reply]

There are also other arguments based on the existing laws of physics in our own universe alone. One can e.g. argue along the lines of the simulation hypothesis. Many variants of such an an argument are possible. One can argue that our own brains simulate a virtual world and that we actually only experience events in this virtual world and not the real world. By construction this virtual world evolves in lockstep with the real world, but the correspondence between the real world and the virtual world generated by the brain isn't perfect and in case of certain mental conditions, the difference can be quite large. One can then argue that Tegmark's MUH restricted to computable universes could then be true, because one can consider computers simulating any particular member of the ensemble of all computable universes within our own universe. All possible simulations must then actually be carried out somewhere in our universe. This could be true if the universe is large enough or will continue to exist for a large enough time. Count Iblis (talk) 22:03, 5 March 2019 (UTC)[reply]