Let's say 200 years ago it was discovered that gold has the atomic number 79.
My claim: possibility is conceivability without known defeaters.
201 years ago it was possible (because it was conceivable) that gold had any atomic number except for the ones which they'd already mapped (hydrogen=1, helium=2 were known defeaters against gold being 1 or 2). Note: and they may have known of some upper bound of stability which it couldn't be bigger than. So it may have been possible for the atomic number to be greater than 2 but less that (e.g.) 250.
Today it is not possible that gold has any atomic number other than 79 because the notion of any other weight is defeated by the evidence we've collected. Today's child may think it is possible that gold could have any atomic weight, but the child's claim would be incorrect relative to what today's educated people know. Also, the well educated adult from 201 years ago's claim is incorrect relative to today's knowledge, but relative to their knowledge 201 year ago, it was correct.
Similarly, we can safely assume that many of our current claims about possible states of affairs will be false relative to some future level of knowledge. However, today they are perfectly assertable/true/acceptable. Frankly, I'd think in this view, possibility claims are only ever assertable, never true (although 'true' is an easy shorthand, just like how scientific theories and the existence of their entities are 'true').
Robust views of possibility are not needed to explain why we make statements about possibility. Possibility statements are certainly useful, given our lack of knowledge, need for personal accountability, and sometimes just unwillingness to perform the required calculation, so I wouldn't suggest we stop using them.
Possibility is thus either epistemic or instrumental and therefore isn't required in our metaphysics.
Kripke's claim: no.
Explain.
- Jason Christie
Subscribe to:
Post Comments (Atom)
10 comments:
Just so I get it: Am I right to think that Kripke argues that, in fact, it was not metaphysically possible 201 years ago that gold have any atomic number other than the one it in fact has/had. So, it may have been epistemically possible, it still wasn't metaphysically possible 201 years ago that gold had any atomic number other than 79?
Doesn't this suggest that there is a class of statements (maybe the theoretical identifications in science, for example) according to which there is, strictly speaking, only epistemic possiblity. Why do cases like this suggest the stronger claim that there is NO metaphysical possiblity whatsoever?
Adam, yes, I think so. Chris is the expert, but I think on Kripke's view, since gold=atomic number 79 is an important identity, it's not metaphysically possible that it has any other atomic number. What we've been pointing to when we've pointed to that thing we labeled gold has always been 'that thing with atomic number-79', we just didn't always know it (so only epistemically possible).
In regards to the second paragraph, are you able to produce a set of claims that this account cannot handle? If it can handle all the cases, great, it exhaustively explains all of our views on modality, which means we have no justified reason to include real possibility in our metaphysics. If it can't handle all the cases, then genuine modality may be required.***
I'd claim that this handles all the cases.
***There's the further option that we have no justified reason to include something in our metaphysics, but unbeknownst to us it's actually there. In this case, you'd still be unjustified in believing that it is there, given the stipulated lack of evidence. I'll just take it for granted that justification is a valued value when designing explanatory models.
I haven't read kripke's claims on this matter, but here's what he may be getting at:
Whether or not there are humans around, it's absolutely impossible for gold to be anything other than the element with atomic number 79. So, in some sense, we're right about our possibility claim and the people of 201 years ago were wrong. Keep in mind, we're right about a modal claim, and they're wrong about a modal claim. In a similar sense, there are probably modal claims that we too are wrong about. Under your proposed view this is impossible.
However, this is a result that merely points out a clash of intuition. I'm sure a proponent of your view would be willing to accept that we're (in the robust sense) wrong about all modal claims of the form "x could be other than it is".
I think it's worth pointing something out. Consider the above claim that all posative counter-factual modal claims are false. I'd say this would need more defense than "we could get by without it". Our primitive distinctions between "necessarily", "actually", and "possibly" are just as valid as our distinctions between "will be", "is" and "was". Frankly our ontology could get by without the latter with a simple explanation of why we see things in terms of time as well. But in some sense, we respect our fundamental rational judgement as data (even if it is defeasable).
as I said, clash of intuition.
There must be something I'm not fully getting here with respect to the distinction between metaphysical and epistemic possibility.
I can understand that it is not metaphysically possible, and never was, that water have the molecular structure XYZ. This is because water has, and always has had, the molecular structure H2O.
SO, if this is right, then the first part of the account of possiblity in the original post (according to which it was possible 201 years ago that gold have A.N.34) is off the mark. It never was possible.
However, gather up as much empirical evidence you like, and for as long as you like, and it still seems like the statement "it is metaphysically possible that I be one inch shorter than I in fact am" is true.
Or no?
Dan, on this account possibility is best read as assertability, not truth. [Since truth usually means a relation of correspondence between the statements (or propositions) and the way the universe actually is, whereas assertability is a relation between statements (or propositions) and a body of knowledge. My central claim denies that there can be anything for the statements to correspond to since possibility isn't really in the universe.]
Second, it's certainly possible that our current statements can be not assertable. If the reputable scientific community says they aren't assertable, then they aren't. Their claims can be assertable or not relative to some other (future?) community's knowledge. The claims of the current scientific community will always be assertable relative to themselves; it can't not be that way. Therefore current claims made by our scientific community can never be deemed 'false' at the time in which they are made, since those people who are making them are the same people as those who judge them.
It will be hard to get in the headspace of this view without first dropping the assumption that possibility statements are true or false via correspondence to the facts. Backbreaking problems in philosophy can be solved by switching truth for assertability.
Regarding the acceptability of "things can be other than they are." If I put my necessitarian hat on, that's an easy disagreement for many reasons. My central claim here that 'there is no such thing as real possibility' certainly coheres with determinism. However, in daily life we (foolishly?) consider things that happen to be contingent. So, the way things actually happened doesn't count as a defeater (relative to the beliefs of people as they go about their daily lives). But relative to a model which assumes determinism, yes, the claim that "things could have been other than they were" is not assertable.
However, fear not! Science will always be in the dark on some things, so there will always be a place for assertable possibility claims. Not knowing the causes of things, such as why things happened as they did yesterday, opens the door for possibility statements about yesterday. Plus, as I first mentioned, we (instrumentally) need to keep people accountable for their actions, and if we fully embrace determinism we can't do that, so our everyday speech has to allow possibility talk to be assertable. But that doesn't mean we need our metaphysics to be so. So, if we are really put to the question, we are determinists, but in daily life we have instrumental reasons for not acting/talking like we are.
As for the intuition thing, perhaps it is a clash. To me, if you can explain the happenings of the world without needing gods, and you can explain why people have visions, why almost every culture has some sort of deity, why so many people believe in them, etc., and if these explanations satisfactorily explain the data, then gods have been explained away and they shouldn't show up in metaphysics. Or, at least they shouldn't be there anymore than griffons and other fictional entities. I think that's what I'm up to here; trying to explain the uses of possibility without needing genuine possibility to do so. If this isn't deemed an acceptable way of eliminating something from metaphysics, well then yes, a clash of intuitions.
A question: what do you mean by "our fundamental rational judgments?"
Adam, what you've mentioned is Kripke's view, and yes, my view is not compatible with his. I'd claim he's off the mark with his robust metaphysics where none is required. His view also gives us no epistemic way to evaluate modal claims (I can't go check on uninstantiated events or possible worlds). Although his view might be intuitive (as correspondence views usually are), mine is reductionist, and reductionist views aren't intended to be intuitive. They are intended to be explanatory and useful. I can explain possibility such that our metaphysics has one less thing in it. (Most importantly) I can specify exactly when something is possible or not in a way which allows you to go out and check for yourself. Losing out on it being intuitive is, I think, a small price to pay; h20 is water is not intuitive either, but so what?
To reply to your 2nd question, we first need to setup an identity theory. Afterall, we can't determine how you *can* be without first determining who you are and what defines you. I'll try to follow what I think Kripke should be committed to, although he probably isn't for some silly reason such as 'people are importantly different from rocks'.
Insert some sort of identity theory:
If A#79=gold, then by rough analogy Adam's genes=Adam. Let's take this as one defining characteristic of Adam-hood. Any individual which has exactly Adam's genes is Adam. In order to be Adam, the individual must also have won 'most likely to be a long-haul truck driver' from Learning Is Cool high school in 2001 (Adam actually did this). There are other moments in Adam's life which singularly define Adam-hood, but none of them are height related and they are all kept consistent in the Adam who we imagine is 1" shorter.
Note: This ID theory doesn't need to be plausible; I just needed some ID theory to work with.
Background info:
Genes determine the max and min height of individuals and diet and maybe some other factors like injury determine where in that range they actually fall.
So, now let's say we empirically determine that Adam's genes give him a minimum height of 6'2 (when he is his current age, whatever that is). Adam's real height is currently 6'2 (I'm guessing, assume it is true). In other words, Adam had terrible nutrition growing up and grew to be the smallest height his genes allowed.
We can now say, plausibly I think, given our ID theory and the gathering of empirical information, it is *not* possible for Adam to be shorter than he actually is. He can be taller, given better nutrition, but not shorter. Although we can certainly imagine him being shorter, our knowledge of his genes, and our ID theory defeat this imaginable option. So, the gathering of empirical information actually has limited the (metaphysical) possibility.
If on the other hand your ID theory says: "There are no restrictions whatsoever on how Adam can be", then it's in principle impossible to ever specify a defeater and limit the possibilities (construed as I do) of how you can be. The effects of what empirical knowledge can limit depend on the ID theory being employed.
P.S. I don't expect that is actually Kripke's ID theory, but if A#79=gold, then Adam's genes=Adam isn't that crazy.
I've said way too much.
So assertability is a relation between propositions and a body of knowledge. Unless you abandon excluded middle, and these are meaningful propositions, these are either true or false. Under your view they are true or false relative to a body of knowledge, fine. I believe I acknowledged that much in the last post. This is, again epistemic possibility. I don't see any dissagreement there.
However, "things could have been other than they are" is not an epistemic possibility claim (on our current reading). It is to be judged in terms of truth. And it is either true of false (surely you agree with this, or else this debate is about nothing).
I believe a central dissagreement here is an epistemological one (haha, sorry to state the obvious). Your aim is explaining data, mine is obtaining truth. While creating theories to explain data is a big part of that, it's not the whole story. If something is believed to exist for alternate reasons, then it's actually a drawback to a theory if it's excluded. I'm sure you'd claim that any alternate reason would count as data, but I'm thinking more in terms of evidence. The difference being, evidence is not explained, rather it yeilds justification. As far as justification goes, I see more evidence against determinism than for it (even within science, definitely otherwise). To chalk up all that to ignorance seems quite a leap to me. I don't doubt it makes a tidier metaphysics (a metaphysics without time would also be cleaner), but that's rarely a pivotal point when discussing a philosophical claim. What you seem to take as the most important guide to truth I see as a mere matter of philosophical elegance or utility (as you stated was one of your goals).
p.s. fundamental rational judgements I'd say are rational judgements not derived from other propositions that yeild justification to a claim
Defend your honour!
Although arguments have been leveled against me, Chris finds his students have not yet provided the key reason(s) why all possibility claims cannot be purely an epistemic matter. In other words, why not metaphysical necessity in all things, and possibility claims are gaps in our knowledge? Prove that your summer wasn't spent twiddling your thumbs talking about nonsense (although the beer was an upside; I'd rather twiddle my thumbs with a beer than without).
My challenge is this: give me an example that possibility as purely epistemic/scientific ignorance cannot explain.
The ones provided have danced around the issue, but I think I can handle them. Chris firmly believes that the argument is out there.
Adam, I'll get back to you on the formal stuff later.
Dan, I want to keep this clean for the defense of your honour, so only a short reply. If the claim 'Things could have been other than they are' is a metaphysical claim to be judged in terms of truth, then it is false. Necessarily false in fact (just as all things are necessarily exactly as they are). If it is an epistemic claim, it is assertable.
As far as I can tell from what you have said, the view you defend is either that there is no metaphysical possibility in reality, or that everything is metaphysically necessary and that possibility 'claims' are just gaps in our epistemic aquaintance with (necessary) reality. I suspect it's the latter; I don't see how it could be both.
I also think it has been established that Kripke/Putnam arguments would block the first interpretation. So, I'll assume the second (this is partly why I had been asking for a formal argument).
A second thing that I'm not sure about is what a 'robust' metaphysics of possibility is. I think a better way to understand what's going on in modal metaphysics is as a debate between competing metaphysical views on how best to account for our ontological commitments. But your view is ontologically committed to possibility as much as a modal realist is committed to possibility, so long as necessity implies possibility. If everything is metaphysically necessary, then everything is metaphysically possible. What I think your view might be getting at is some sort of extreme essentialism about the actual world. What I don't get, I think, is the move from the claim that the actual world is necessarily the way the actual world is (which might be true, I guess) to the assumption that it is not possible that some other *way* be actual.
It seems also like it is important to note that the apparatus of modality that you find objectionable, or a realist commitment to possible worlds, is thought by some philosophers to be good for more than just giving an account of modality. We might, for instance, believe in possiblia because we think that possiblia are needed to capture what thought in general is about (not just modal thought). This is Bricker's line, for instance.
So, if you think that possiblia can be used to provide an account of intentionality generally, and modality derivatively, then this seems like another reason to be ontologically committed to possibilia.
1) It's the latter.
2) robust possibility I was using to denote an ontology which is committed to some things being contingent. A shorthand I should have done without for the sake of clarity.
"What I don't get, I think, is the move from the claim that the actual world is necessarily the way the actual world is (which might be true, I guess) to the assumption that it is not possible that some other *way* be actual."
It seems to me uncontroversial that the only 2 reasons why anything would ever be justifiably posited would be if (a) we have good evidence for it, or (b) we need it for explanation.
So my counterquestion is, do we have (a)? It seems to me to be, in principle, impossible to have evidence for uninstantiated situations. How could you ever get that? When a die is rolled and comes up 3, I have access to the object which has 3 as its upward facing side, and I have access to my thoughts about the other options. I don't, and can't, have access to the event of it having been rolled a 2 (at the same time).
Although we can think of uninstantiated things, that isn't good evidence. We can think of ghosts, unicorns, and 90' rats attacking the cheese moon too, but presumably they don't exist.
What about (b)? I'm trying to give an account of possibility which is purely epistemic and mind dependent.
This is I suspect, coincidentally, conceptual turn stuff. I'm saying all there is is our concept of possibility; there is no real (reason for accepting) possibility.
"We might, for instance, believe in possiblia because we think that possiblia are needed to capture what thought in general is about (not just modal thought)."
That seems to me to be putting the cart in front of the horse, but yes, that _could_ be a good reason. Since I don't know the argument I can't comment on it, but I hope it doesn't say something like 'we need possibilia genuinely out there, because only if it's out there can we think about it.' That would be gross.
P.S. I actually like Lewis' model for counterfactuals; it's a useful model. Lewis was a realist about his model because he wanted his account to be reductive. That makes sense actually; if it is a useful model and we have no other ways of explaining things, that's a good reason to be a realist.
Post a Comment