An Argument Against Concrete Possible Worlds
When we say that something could have happened differently, what do we actually mean?
David Lewis proposes an answer to this question. In non-technical terms, he proposes that when we talk about possibilities, or what could have happened, we’re saying that there exists a world where that does happen.
For example, if I said “my cousin could have been an engineer”, Lewis says that what I mean by this is that there exists a world in which my cousin actually is an engineer. Similarly, if I say “it is possible for that tree to be struck by lightning”, Lewis says that what I mean by this is that there exists a world in which that tree is struck by lightning.
Now, it may be that the possible world that I’m talking about is actually our own world. That is, it may be that the tree I was talking about is actually struck by lightning. In that case, I would realize that the possible world I was talking about before (where the tree is struck by lightning), is actually our own world.
Because of situations like this, Lewis is very careful to point out that when we say something is “actual” or “real”, it just means that we’re talking about the world that we live in. In each of those other worlds, if someone talks about what’s “actual” or “real”, they’re talking about the world that they live in. Since we live in this world, everything that happens in this world is actually happening — it’s real — to us.
The idea that other possible worlds exist in the same way that this world exists is called concretism. The name comes from the idea that those possible worlds are “concrete” because they exist in the same way our world does. They’re not just “abstract” concepts.
I don’t think that concretism is correct. What follows is my argument as to why I think Lewis and other people who believe in concretism are wrong.
First of all, I think this theory is just one possible way of looking at what we mean when we say that something could have happened or that something is possible. I think there are many different theories, and all of them might be right.
To state this slightly more explicitly, I think it’s possible that concretism is wrong.
However, concretism can deal with that. Since I merely think that it’s possible that concretism is wrong, concretism says that there’s some other world in which concretism is wrong. What would that look like? Well, in that world, when other people say that something is possible, they wouldn’t mean that there’s a world that exists in which that event takes place. They would mean something else. In that world, concretism would be wrong.
This works just fine for concretism, and I think it’s a common first response that people make when they hear my argument.
But I want to push this line of reasoning slightly further. Not only do I think that it’s possible that concretism is wrong, I think that it’s possible that concretism is actually wrong.
If we assume that it’s possible that concretism is actually wrong, then it follows that
- There exists a world in which concretism is wrong (because it’s possible)
- We’re in that world (because it’s the actual world)
- Thus, concretism is actually incorrect (since we’re in the world where concretism is wrong)
Now, it may seem as though I just assumed that concretism is incorrect and then used that to prove that concretism is incorrect. However, if you’ll look carefully, you’ll see that that’s not my assumption. My assumption is that it’s possible that concretism is actually incorrect.
To me, at least, it seems highly unlikely that concretism is the only actually correct theory. It seems extremely likely, or, at the very least, possible that some other theory is actually correct.
But my proof above shows that if you believe that it’s possible that concretism is actually wrong, then it logically follows that concretism is actually wrong.
This means that if you’re going to believe in concretism, you are forced to believe that no other theory is possible. To me, that seems like an extremely bad standpoint to take as a philosopher.
Overall, my general critique is that any theory about what possibility means should allow for at least the possibility that the theory itself is actually incorrect. Unfortunately, concretism does not do this. If I assume that it’s possible that concretism is actually wrong, concretism tells me that it is wrong. And I think there are a lot of people who believe that it’s possible that concretism may actually be wrong, but still believe that concretism is a plausible theory. This critique shows that those two beliefs are logically incompatible.
Why I may be wrong:
It could be that I am incorrect in my interpretation of the term “actual”. For example, it might be that according to concretism, when we say “it’s possible that concretism is actually wrong”, concretism interprets that to mean that there exists some world, where, for the people in that world, concretism is actually wrong. That is, the interpretation is exactly the same as the earlier (non-actual) case of “it’s possible that concretism is wrong”.
However, if this is the interpretation, then it seems like concretism is not allowing us to say anything about our own world. We’re always stipulating things about other worlds that are never our own world. And to me, that’s not what possibility means. Often times when talking about possibilities, we’re talking about our own world. If I say “it’s possible that this tree is actually dead”, I’m not saying that there exists some other world in which the tree is dead, and for those people, the tree is dead. I’m saying that the tree may be dead to me, in my world.
Personally, I hope that this critique is weaker than it appears to be to me. I rather like thinking that when people say lines like “it’s possible that things could have gone better”, there’s some world out there where things actually did go better.
If you happen to see some flaw in my argument, or if I’m misrepresenting what concretism is, please let me know in the comments.
Also, please note that I try really hard to make these ideas accessible to everyone, so no matter how old you are, or what you’ve studied, I’d love to hear your thoughts on this. My goal is to spark conversation about these ideas, especially since they’re so commonly used in philosophy.