So if there’s one subject I’m not too familiar with in PHIL 460, it’s laws of nature. It’s not that they’re actually that hard to understand, but Dretske is just so darn confusing. ;_;
So, what’s the problem with laws of nature? It’s in the definition — what is a law of nature? Is it just a true generalisation, as a regularist would say, that holds across all time and all places? Is the ideal gas law an actual law? What about the law of supply and demand? Or the Law of the Conservation of Energy? What about mathematical laws? So many questions!
The empiricist response would be that laws are actually a sub-class of true generalisations. So laws may imply true generalisations, but true generalisations don’t necessarily imply laws (i.e., the regularists are wrong).
Fred Dretske is one guy who tackled this problem by appealing to universals to distinguish laws from no-laws. He says we should make a singular statement about properties and quantities and use that as a law. If you look at pV = nRT, this makes sense. That law is all about the relationships between properties and quantities. Dretske puts his kind of law in the form: F-ness –> G-ness (because all F’s are G’s). The law implies the universal generalisation (x)(Fx entails Gx), but the generalisation on its own doesn’t imply that F-ness necessitates G-ness. But WHY? Why is F-ness –> G-ness so special? How does it relate to the universal generalisation?
He writes a lot that takes down opposing views, but I’m still not really sure why he thinks his is necessarily true. This is why I’m really confused about this topic. But anyway…
He goes on to say a lot of things about what laws are, including that they are opaque statements. Well, what does that mean? Opaque statements are special statements that don’t maintain their truthfulness if you substitute their coextensive properties. So “it is the case that all hairy creatures have hair” is transparent but “necessarily, all hairy creatures have hair” is opaque. WHAT. This somehow proves that laws can’t just be universal truths. I have no idea what’s going on with this argument, but basically universal truths are transparent and laws are opaque, therefore universal truths don’t imply laws.
Everyone gets this argument except me, clearly, because the regularists respond to it by saying that laws ARE universal truths… only with an extra somethin’ somethin’ that explains the opacity. So by a regularist account, a law = universal truth + X, where X is a magical factor that accounts for opacity. X is often said to be some pragmatic or epistemic virtue, like having a high degree of confirmation (epistemic) or predictive use (pragmatic).
Dretske says NOPE, X can’t be epistemic or pragmatic, because laws don’t begin to be laws when we become aware of them. I think this is actually his best argument (maybe because it’s one that I actually understand). He quite rightly says:
“We discover laws, we do not invent them — although, of course, some invention may be involved in our manner of expressing or codifying these laws.”
He goes on to say that laws can be confirmed by instances, whereas universal generalisations cannot receive confirmation for next-case induction if you phrase them as (x)(Fx entails Gx). He says that for F-ness –> G-ness, though, you can have positive instances that raise the probability that the next F will be G. I thought I understood this but turns out it’s actually kind of confusing.
There’s a coin-toss example where you assume a fair coin, but when you flip it 9 times you find it lands heads all 9 times. What’s the probability that the next flip will result in heads? It’s the same as before you started – 50%. The flipping trials did not increase the next case probability.
What if you made a mini-law that the coin was asymmetrical in some aspect, resulting in a heads bias? Then there could be next-case confirmation, and you could say the chance that the 10th flip would result in heads is greater than 50%. This is supposed to demonstrate that positive instances can raise the probability of the law but not of a universal generalisation.
He also says that laws explain and universal generalisations don’t. It might be a universal truth that all ravens are black, but it doesn’t tell you WHY all ravens are black. Universal generalisations just summarise instances, and don’t tell you anything about them. Laws supposedly explain stuff. He moves on really quickly from this point so I haven’t got much to say.
His next point, which is also pretty strong, is that universal generalisations can’t support counterfactuals and laws can. The example given is about all dogs being born at sea being cocker spaniels.
Universal generalisation: All dogs ever born at sea have been and will be cocker spaniels.
Law: It is a law that dogs born at sea are cocker spaniels.
In the first case, we can think of cases where we bring other dogs out to sea and breed them. Would we get cocker spaniel pups if we bred two Dalmatians at sea? Why would anyone say this unless they thought that this person knew some crazy law that prevents other types of dogs from being born at sea, so it is the law that is presumed to ensure the “continuance of a past regularity” and that supports the counterfactual. Lolwhat. No idea what’s gong on, but sure. The law supports the counterfactual and the universal generalisation doesn’t because it’s based on some sort of law. I like cocker spaniels?
FINALLY, he says that laws have modal import and universal generalisations don’t. Laws say what MUST happen (like actual laws in the field of law) and generalisations just describe what happens.
There are a lot of objections to Dretske, including the question of how we can confirm and know laws in the first place. Also, we still don’t know why the abstract relation between universal F-ness and G-ness implies the universal generalisation. What makes it so special? As has been pointed out by C. S. Lewis (and quoted elsewhere):
“[L]abelling the relevant relation a ‘necessitation relation’ cannot by itself create a necessary link between the related things, anymore than calling someone ‘Armstrong’ can give them mighty biceps…”
I.e., just ’cause Dretske says that the N-relation (the relation between F-ness and G-ness) implies a universal generalisation, doesn’t make it true.
There’s also an objection related to counterlegals, and the idea that laws could be different and we can imagine them being different. This is difficult to represent if laws are relations between abstract properties, and difficult to explain if laws that exist in our world don’t exist elsewhere. If F-ness –> G-ness is only true on Earth, it’s not a law because it doesn’t support counterfactuals. If F-ness –> G-ness is true EVERYWHERE, then laws are the same in other worlds and everywhere. If F-ness –> G-ness if true in some places but not others, then why should we prefer that over (x)(Fx entails Gx)?
So in the end, what is a law of nature? I don’t know. Maybe Nancy Cartwright has some answers?
Scientific Student 