So there's this world. Take the world to be everything. That is, everything there is. Worlds aren't planets, they're whole realms of being. So everything that you think of as true is true of this world. Now take one of those truths...for instance, Joe Biden is vice president. Now, you might want to say that the proposition expressed by the sentence "Joe Biden is vice president" has interesting properties besides being true. It also has the property of being contingent. That is, it didn't have to be true, and that's an interesting difference between the proposition expressed by "Joe Biden is vice president" and "all triangles are trilateral". The latter proposition couldn't have been false, or, as we say it, it is necessarily true. Additionally, even though the proposition expressed by "Sarah Palin is vice president" is false, it's not false in the same way that "the sum of seven and four is seven" is false", for the former is possible. It could have been true, and the latter couldn't have been. But what is contingency? what is possibility? what is necessity? Well, before trying to figure out what those properties are we might try to figure out how the predicates is necessary, is contingent, and is possible contribute to the truth conditions of sentences in which they appear. Here's what I mean by that: think of the truth conditions for "Robert sits." That sentence is true if a person, named Robert, is sitting. Think of all of the possible situations in which 'Robert sits' is true, and what they all have in common; that common ground amounts to the truth conditions for 'Robert sits'. Now consider "in the rain", and imagine attaching that to our original sentence, "Robert sits", so now we've got, 'Robert sits in the rain'. The truth conditions for that sentence have been affected; whereas earlier, all of the situations in which Robert was sitting met the truth conditions for Robert sits, now all of those situations in which it wasn't raining where Robert sits have been disqualified. The truth conditions have tightened up, so that only situations in which it's raining where Robert sits survives. That's the effect that 'it is raining' had upon the truth conditions of 'Robert sits'. Now...what were we talking about again?
Oh, right. Possibility. So now think of the truth conditions for 'Robert sits'. Now: 'Possibly Robert sits'. What has changed? Well now we've got a more liberal sentence, a sentence which is true in circumstances where Robert isn't sitting (maybe he's swimming) but where he could have been (if he had gotten out of the pool when the life guard yelled at him). So what's just happened? what is the influence of 'Possibly...' upon the truth conditions of a sentence?
Oh, right. Possibility. So now think of the truth conditions for 'Robert sits'. Now: 'Possibly Robert sits'. What has changed? Well now we've got a more liberal sentence, a sentence which is true in circumstances where Robert isn't sitting (maybe he's swimming) but where he could have been (if he had gotten out of the pool when the life guard yelled at him). So what's just happened? what is the influence of 'Possibly...' upon the truth conditions of a sentence?
One common way to model that influence is in terms of possible worlds. So, remember we were talking about our world, which contains everything that is. but there are other ways that the world could have been. For instance, I could be standing right now. Or McCain could have won the election. Or the gravitational constant could have been slightly different. Or there could have been only two objects. These are all, what we call, possible worlds. They are extraordinarily useful. They allow us to make sense of the contribution that qualifiers like 'necessarily' and 'possibly' make to sentences. Something is necessarily true if its true at all possible worlds. something is possibly true if it's true at at least one possible world. Something is contingently true if its false at this world but true at some other possible world.
There's much to be said about possible worlds. There is much work to which they can be put. Not only are they useful in talking about modality (neccessity, possibility) but also properties (sets of possible individuals, or functions from worlds to sets of individuals) propositions (sets of possible worlds, on some views), reference (who does t pick out on world w?) and etc.
What's most interesting to me is that worlds have all of the properties of the perspectives that I introduced last week. There are the locii of truth (that is, propositions are true at worlds) and they can diverge from one another concerning which propositions are true (p can be true at w and false at w'). What's more, among the things true from our perspective (on our world) there are interesting categories to divide the truths into, the necessary and the contingent. To parsing out the contingent truths from the necessary truths is to investigate the fluidity, the flexibility in reality as such, and what reality as such would permit, while to return our focus to the necessary truths would be to investigate the immutability and the inescapability of certain features of reality as such. The fact that I am sitting is an interesting fact about the way that the world is, but it's not an interesting fact about what is inescapably the case just in virtue of the way reality in itself is. On the other hand, that all triangles are trilateral actually is an interesting feature, not just of our world, but of any possible world, and thus a feature of reality at its very core.
As a species of perspectives, possible worlds invite the same questions of ontological status and privelege as other perspectives. There is a strong intuition that the world we are on (the actual world) is more real than all of the worlds that are possible but are not actual. This mainstream view would either attempt to claim that there is no need for the theoretical work that possible worlds do, or else they want to try and reap all of the benefits from possible worlds using only the resources of an ontology according to which only the actual world exists. These latter strategists often invoke abstracta.
We might wonder whether there are ineliminable modal facts, that is, propositions constitued, in part, by modal concepts like neccessity or possibility, which could not be reduced, recast, or translated into non-modal concepts.
So those are possible worlds, and there's a taste of my style of worrying about possible worlds. This strikes many as a rather silly way to worry about it, but its motivated by a sense that our world isn't so snubnosed and monolithic as to unproblematically and unqualifiedly be constructed out of actualistic resources. There's something fluid, flexible, bendable about the way the world is, and that this is an ineliminable feature of the way that things are. Modality is here to stay, and the resources necessary to make sense of it deserve our respect and consideration.
Or maybe it isn't and they don't. But in ane event, I'll have a lot to say about possible worlds.
There's much to be said about possible worlds. There is much work to which they can be put. Not only are they useful in talking about modality (neccessity, possibility) but also properties (sets of possible individuals, or functions from worlds to sets of individuals) propositions (sets of possible worlds, on some views), reference (who does t pick out on world w?) and etc.
What's most interesting to me is that worlds have all of the properties of the perspectives that I introduced last week. There are the locii of truth (that is, propositions are true at worlds) and they can diverge from one another concerning which propositions are true (p can be true at w and false at w'). What's more, among the things true from our perspective (on our world) there are interesting categories to divide the truths into, the necessary and the contingent. To parsing out the contingent truths from the necessary truths is to investigate the fluidity, the flexibility in reality as such, and what reality as such would permit, while to return our focus to the necessary truths would be to investigate the immutability and the inescapability of certain features of reality as such. The fact that I am sitting is an interesting fact about the way that the world is, but it's not an interesting fact about what is inescapably the case just in virtue of the way reality in itself is. On the other hand, that all triangles are trilateral actually is an interesting feature, not just of our world, but of any possible world, and thus a feature of reality at its very core.
As a species of perspectives, possible worlds invite the same questions of ontological status and privelege as other perspectives. There is a strong intuition that the world we are on (the actual world) is more real than all of the worlds that are possible but are not actual. This mainstream view would either attempt to claim that there is no need for the theoretical work that possible worlds do, or else they want to try and reap all of the benefits from possible worlds using only the resources of an ontology according to which only the actual world exists. These latter strategists often invoke abstracta.
We might wonder whether there are ineliminable modal facts, that is, propositions constitued, in part, by modal concepts like neccessity or possibility, which could not be reduced, recast, or translated into non-modal concepts.
So those are possible worlds, and there's a taste of my style of worrying about possible worlds. This strikes many as a rather silly way to worry about it, but its motivated by a sense that our world isn't so snubnosed and monolithic as to unproblematically and unqualifiedly be constructed out of actualistic resources. There's something fluid, flexible, bendable about the way the world is, and that this is an ineliminable feature of the way that things are. Modality is here to stay, and the resources necessary to make sense of it deserve our respect and consideration.
Or maybe it isn't and they don't. But in ane event, I'll have a lot to say about possible worlds.
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