Transcript of Necessitarian Accounts

all right we are continuing to talk about laws of nature Um talked about Hume right and his uh skepticism about sort of necessary connection what that concept even mean which seems to be um something that people want a concept people want to use when they're describing laws of nature something it will necessarily fall to the ground And Hume just couldn't figure out where we get this idea of necessary connection from Um then we had Schwarz who sort of developed that into a full-fledged theory a loss of nature right and his unregularity theory we called it in this account a law of nature is just a true description basically of things that happen there are a few more conditions and it had to be universal not just local um laws just descriptions there's no extra metaphysical oomph right the law of gravity isn't pushing things around or pulling them it's just describing how things behave Then we saw Armstrong who uh had some objections to regularity theory Um and now we're going to see Dretzky who's going to have more Uh I think Dresky he has some some ways to sort of cut to the heart of it I think in a in a different way than Armstrong discussed And uh then Dreski is going to offer another account which is a necessitarian account right it does invoke this idea of necessity and laws of need Okay so before Dretzky sort of attacks regularity theory he wants to uh you know convince you it's worth arguing against So um he sort of summarizes the motivation the reason you might want to believe regularity Um and he he formulates it something like this right so so we observe a lot of Fs being G's I think at this point you should be comfortable terminology could be swans being white objects falling towards accelerating towards zero m/ second squared gases expanding when he right so they have all these observations these correlations um he says according to the regularity theorist right um those observations alone are just never going to provide evidence for any claim that's any stronger than G's right ones are white um not going to give you or likeily white right so he sort of compares uh you know on behalf of the regularity theorist compares this impulse to make the claim stronger to like trying to somehow prove that all bachelors are unmarried surveying bachelors Um just walk up to say are you married or not you say no You say aha proof that bachelors are necessarily unmarried Um I mean that is true right it's an analytic statement so it's going to be necessarily true but you don't prove that it's necessary by just giving examples It's just the wrong kind of evidence for that sort of like modal claim Um and since observation is the only sort of evidence we have for laws of nature um it follows that the strongest claim we can ever make um about laws of nature is just the fact that yeah all solar white right all objects happen to accelerate at this uh at this value So a law again for the regularity theorist just a description of what it is But Resky wants to sort of poke at this problem and he must give some examples that show that um our concept of law what we're thinking about when we talk about a law of nature actually is going to have to be stronger than what regularity theorist claims it is And we've seen this um sort of method a few times in the course Very common method in philosophy where you take someone's account right regularity theorist or the deductive logical kind of explanation and you come up with an example that meets all their criteria for what should be a law of nature or a good explanation or whatever um we show that actually are really bad examples that sort of intuitively we think that does not should not count as a law should not count as an explanation Um he's going to do the same sort of thing Um and here one way that he points this out is uh he shows that laws are opaque They have opacity in a way that just universal generalizations of the regularity theorists not have Um so what do we mean by opacity what he means is that co-extensive predicates are interchangeable right in universal statements but they aren't interchangeable in laws That means that laws are opaque right whereas universal statements are transparent What the heck is a co-extensive predicate um so predicates are just sort of words descriptors right so um is green right is a diamond lives in San Diego right these are descriptions that we can apply to objects properties that objects have That's what a predicate is Um and sometimes they're co-extensive which means they pick out the same set of objects So if I were to say all creatures with a heart and all creatures with a kidney right so these are two separate predicates definitely even different concepts right and yet it just so happens all the things out there that have a heart also have a kidney So they're coextensive right pick out the same set of objects Um and in a universal statement that would be totally interchangeable So if I say um all creatures with a heart breathe oxygen uh I could substitute in all creatures with a kidney breathe oxygen would still come out true right it would be a perfectly good generalization Um but in the case of laws he wants to say that if you do that sort of switching out co-extensive predicates um you can lose sort of the law status of of the statement and his example is this uh all diamonds have a refractive index of 2.419 Um you may recall the a refractive index is just sort of the angle at which light sort of you send light through a diamond it's going to sort of bend come out at a different angle Um so this call this a law of nature right about diamonds uh it just so happens that all diamonds are mined in kimberly so this co-extensive predicate say things mined in kimberlite right that will also pick out all the diamonds um but Dretzky points out if we swap those terms out swap out those predicates if we say all things mined in kimberlite have a refractive index of 2.419 one n that should intuitively strike us as not being a law of nature right um that's sort of an accidental thing Um the reason that diamonds have the refractive index they do presumably is because of their molecular structure right um but being minding kimberlite um and I don't know a ton of geology but let's say that that's not that doesn't affect the molecular structure right um that's just sort of you know it's just sometimes there isn't it's an accidental that right the same set of objects have two same properties There's no lawful connection there between where something is mine and it's refractive index where there should be intuitively there is a lawful connection between substance that it is the sort of molecular structure it has and its refractive index So this is the opacity right you can't just switch out of terms being if you do Okay So this is opacity and if you can make the substitution then we'll call it transparent Um now if you're a philosophy major you may have encountered a different uh kind of opacity So we'll briefly sort of talk about that so we don't get too confused Um we talk about things like people's beliefs Um there's another kind of opacity Uh so for example if I said uh Lois believes Superman saved the day right well if she doesn't know that Superman is Clark Kent then it might actually be false to say that she believes Clark Kent saved the day right um so in the case of belief sort of when it's filtered through somebody's belief um swapping out co-extensive predicates like that can turn a true statement into a false statement Um now it's slightly different in the case of laws right it doesn't turn a true generalization into a false generalization but what it does do is it turns a law into a non-law right by switching out these So it's a different kind of opacity We're still going to call it opacity Now um regularity theorists are not without their response to this sort of objection Um and Dresky sort of summarizes he sort of lumps their general he says this is what they tend to say um tend to say okay you know we note this opacity issue right but they want to say this is not indicative of some fundamental difference between laws and universal generalizations uh rather it's it's just kind of a function of the way we tend to use laws right and they say if you add sort of an ext extra condition right this how we use um the generalization then you won't get this problem so they'll add an extra condition and different people offer different um options right but Dresky list spy right it might be so a law might be universal generalization that is highly confirmed right or it might be widely accepted have uh good explanatory potential It might have deductive integration with a larger set of statements So that means sort of like that it's um there's a whole sort of set of laws and and conditions that you can make derivations from Might be its sort of usefulness for prediction Um so sort of like Dresky sort of lumps these all together says "Okay regularity theorists they get around this opacity problem by saying a law is a universal truth plus and you might see how that could sort of help right so um take explanatory potential um fact that diamonds have this have this uh refractive index Um right you link that up with some laws about the molecular structure of diamonds and and we have sort of we can do sort of a deep explanation of why it has the refractive index it has um if you used things mind in Kimberly instead um it's not going to be as explanatory it's not going to be as helpful you're not going to really understand the deep reason why it has a refractive index buzz um it might be more helpful for prediction right to talk about diamonds rather than just stuff finding Kimberly uh so yeah maybe this helps right but Dresky's not going to buy it um so here he's he's going to tell us necessitarianism right so here here's here's the basic we're going to come back to these some objections to regularity theory but here Dresky wants to sort of lay it on the line what he thinks his view is right um so he wants to argue that this opacity comes right arises not because of like the regularity theorist says some sort of extra fact about the way we happen to use scientific laws who wants to say it's because laws right basic concept of what a law is we all kind of believe in our hearts it's not a relationship between sets of objects it's not a relationship between all the things that happen to be diamonds and all the things that happen to have a particular refractive index rather it's relationship between fness and genus right diamondness right the property of being a diamond and the property of having a particular index Right it's these properties that have this necessary relationship and the objects that have those properties will also have that relationship But it's not in virtue of the objects themselves It's in virtue of the properties This distinction between um a property sort of taken by itself an object having a property might be slightly weird to you because you might think well all there is in the universe is objects Um extra thing right properties on their own that the property of diamond and this floating free of objects Um and yeah it's a little weird Um we'll talk about it later right trex is gonna say you just kind of have to swallow that because um everything else makes sense in this view and regularity theory is so bad that used to it Um okay So what is this distinction again between sort of the property of diamondness and the property and just sort of the set of objects that happen to be diamonds well for any object that happens to be a diamond um there's going to be a lot of predicates that you can apply to it Right it may have the predicate of being owned by Nate predicate of being kept in a box um of being set in a ring right um but none of that is true of it sort of in virtue of it being a diamond right it being a diamond doesn't sort of like pale or necessitate it being owned by Nate But we do want to say that it has the refractive index it has in virtue of it being a diamond right if it has a diamond it's guaranteed to have that refractive index descitated Um and so there seems to be a special subset of the properties right that something can have have a much deeper relationship or lawike relationship and not any true generalization is going to have everything right if we if it were the case the regularity theorist seems to think that we were just talking about groups of objects um then this should be a law right so suppose imagine I'm a super rich sort of super villain I buy up every diamond in the world I keep them in a big box in my secret vault Okay Um so if you said okay everything in a box in Nate's secret vault that would pick out all the diamonds right if I if I had bought them all put them in the box Um it absolutely shouldn't be a law of nature that everything in a box and Nate's secret vault has a refractive index of 2.419 right um tomorrow I could put a marble in there and all of a sudden right that's not going to be true We want laws right to again should have something to do with the fact that they're diamonds not right not with some extra some fact that accidentally picks out the same group of um and Gretzky wants to say yeah that's because the property of diamondness doesn't entail anything about being in my vault right um so if laws are relationships among properties then you're not going to get it's not going to turn out that that's a law that everything in my vault refractive indexes So on the necessitarian view you don't get these bad laws these generalizations that aren't laws And so this is the necessitarian view Um laws are relationships between properties Um later in the in the David Lewis paper we're going to have to talk about sort of more subtle differences between properties and universals For now we don't need to worry so much about it Um okay so we have laws and we have universal generalizations And Dresky says they're different Hence the regularity You know these are two different things Um laws will entail universal generalizations Um but they aren't going to be identical to them and they're not going to be entailed by them So if it's a law right that all diamonds have a refractive index 419 and we also have the extra sort of fact non-law but fact that all diamonds are mined in kimberly then you will get um entail that all things mined in kimberly have index of 2.419 419 that will be a true generalization but it will not be a law again this weird I mentioned this weirdness of like how what is diamondness apart from being a diamond and uh we'll get back to that but before we get back to that Dresky Dresky knows this especially for people that are into metaphysics and they find it very hard to swallow any kind of like sort of like the like metaphysically weird properties He knows it's going to be problematic for some people So he wants to prove to you how hopeless regularity theory is and then he's going to just buy into the existence of time in this overall It's it's just the only way to go So let's look again at how hopeless regularity theory is for him Okay Um here's one problem and I we saw in Armstrong too Uh laws support counterfactuals right and just pure universal generalizations don't um right universal generalizations talk about what is the case but they don't help us too much in talking about what could be the case right if things were done So Dresky's example is um maybe for all we know it's true that all dogs born at sea have been cocker Daniels right suppose that's true um we shouldn't take that to entail that if I oxen on the boat right and the oxin had a baby that it would give birth to a um right that's a that seems false right but the problem is that it seems to be somehow um entailed by the regularity theory right um another example Just because all the marbles in a bag are red right it doesn't imply that if this marble that I hold in my hand if I put it in the bag it would be red right so a blue marble doesn't actually become red by added to a bag So again um these generalizations these just statements of what is don't seem to help us uh predict or talk about what could be There's another way to think about the difference between generalizations and laws and that's about how do we confirm laws right um so suppose uh I want to I have the hypothesis that everyone in this room is over 30 right pick out of some everyone in there is over 30 well if that's just a description of what is right just a generalization then I can confirm that by myself walking into the room because I'm over Right so I've just increased the probability that everyone in the room is over 30 Um but intuitively you show up that's not a good way of confirming the hypothesis right i just made it happen I just walked in the room to make it happen Um doesn't actually affect it doesn't say anything about the probability of the next person entering the room being over 30 It's very useless thing Um right so these just generalizations these statements of things that happen to be facts they're not super explanatory Right what you really want science is is an explanatory hypothesis So if I said this room is hosting my 20th high school reunion right then now we do have some explanatory right um relation between the property of being a 20th high school reunion and being a room full of people over 30 right so laws should explain the world They don't just describe right and we see this in the way that they are confirmed You can have good confirmation right which is confirming laws that are explanatory And you have this really trivial kind of confirmation that you I guess apparently could do if laws were only generalizations but you shouldn't because it's a bad way to confirm Here's just a nice quote So he says "The fact that every F is G fails to explain why any F is G." And it fails to explain it not because its explanatory efforts are through feeble who have attracted our attention but because the explanatory attempt is never even made So the fact that all men are mortal does not explain why you and I are mortal It says in the sense of implies that we are mortal but it doesn't even suggest why this might Right so again these generalizations they're not even trying to explain anything They're just saying what happens to be the case And so you want to if you're going to be a necessitarian of the type right that Dreadsky endorses and you think about laws relationships between properties you're going to solve all these problems right so the property of being a diamond is what entails its refractive index right again property of being a diamond has a certain molecular structure that's going to tell you what the refractive index will be The property of where it was mined is not going to explain anything allow you to predict anything Um being a 20th high school reunion is what entails and explains why the room is full of people over there Um counterfactual So if this rock were a diamond right so suppose I'm holding a piece of granite right i can say well if it were a diamond it would have this particular refractive index Again universal generalizations don't help us factuals because they only describe what is the case Um on this necessitarian view as laws relationships between universals uh doesn't turn out to be a law that all dogs born at sea are cocker spananiels Um again there's no connection between the property of being born at sea and being a cocker spaniel Um none of this depends on us and what we know right properties are out there whether right we know them or not they exist relationships between them exist and that the laws are there for us to discover right but they're not in any way sort of like dependent on human investigation And he does this sort of metaphor which may be helpful for some people right if you're having trouble with this idea of like what and how how do we have a universal that's different from an object that has the property like what are we talking about so he describes universals as like a political office right so um you know you have president governor whatever I think over here I have the California the executive branch all the various offices the governor lieutenant governor secretary of state legislative branch and so on So different objects can fill those offices right so we change every four years or so But that doesn't change how those people behave in certain ways So they their behavior is constrained by the office itself right and there are relationships that hold between the offices regardless of who fills those offices It's all set up in the state constitution So he kind of wants to say universals in the laws their relations they're sort of like constitution right that the universe is constitution and whatever object may fill those roles or instantiate those properties is not um what makes the law a law right it's the relationships between those offices And again this isn't the same sort of necessity as uh analytic necessity So all bachelors are unmarried This is just true in virtue of the concept of being a bachelor and being married and sort of like a logical necessity based on the meanings of the terms But laws of nature are not logically necessary in the way that 2 plus 2 equals 4 is logically necessary right um maybe that's a a better example than the bachelor's unmarried Anyways but it's not remember back to Hume right week one um it's not like contradict contradictory to imagine that a diamond has a different attractive index in it So in the in the way that it would probably be contradictory I think to think of a bachelor as being unmarried Um these laws are not sort of laws of logic They're laws of nature They could be otherwise right um but they just happen to be the way they are Um okay So they're not necessary in they're necessary in a one way not logically necessary but what we call nomologically necessary right they are um nomalological again you encountered that word in the DNx model of explanation as laws so whatever necessity is involved is conditional on the nature of prophecys if you're filling the office of being an object near the earth then um you will necessarily accelerate towards the earth 9.81 81 meters per second You know once we understand what it is to be a a G and to be an F then right there's a law to the effect that all G Fs are G's And if you're a G you must be an F And it allows us though the the leeway to understand what it means to say well if I were an F I would be a G even if I'm not an F So if I were sheriff of Los Angeles County I would be required to enforce the laws implemented by the state legislative body That would be the case for anyone that happened to be the sheriff right um those counterfactuals totally make sense if you think about as relationships of offices instead of sort of the way object and just these universal generalizations can't capture this right they only talk about what is tell us what could happen Okay so this for Dresky is why laws explain laws are relationships between universals And this is sort of a nice quote I thought So the period of a pendulum decreases when we shorten the length of the bob Not just because all pendulums do that but because the period and the length are related in a particular fashion right um again this is the ex this conception of laws gives us some explanations right rather than just saying "Oh uh that's a law because that's what things do right?" Okay so back to what the heck what is diamondness right what are you talking about right aren't there just diamonds in the world there's no extra property of diamonds I believe in that Um and there's lots of talk about this in the world of metaphysics We're not going to get into it Um Dresky doesn't really get into it either He says "Look without universals you just don't get good laws right you just get these generalizations that are kind of like um don't do all the things we want laws to do." And he says "You don't you want laws of nature?" Right they're good things They help do a lot They explain the world They help us predict So um says "Get over it." Right there are universals Um in the next lecture we are going to Lewis and he's going to have an account that is a sort of regularity account that tackles just this weirdness and he wants to say I I don't have to believe in universals in order to get all the good stuff out of laws of we will look at that one in the next lecture