One of the reasons philosophers are prone to accept possible worlds into their metaphysical worldview is to find truthmakers for counterfactual claims. If I say “The cat is on the mat”, the truthmaker for the claim is the fact that the cat is on the mat. However, if I say “If I hadn’t caught that egg it would have hit the ground”, what is the truthmaker for this claim? Because the claim is about something that didn’t actually happen, we can’t just point out the truthmaker as we did with the cat being on the mat. So what grounds the truth of the counterfactual claim? Such questions have led philosophers to posit the existence of possible worlds to ground the truth claims of counterfactuals. So the idea is that there is some possible world where I failed to catch the egg and it splatters. It is this possible world that grounds the truth of the counterfactual claim.
But before we accept the existence of possible worlds into our metaphysics, we should ask ourselves whether counterfactual claims even need truthmakers. After all, not every speech act needs to have a truthmaker. Take commands, for example. If I say to you “Pick up that pen”, what is the truthmaker for this claim? It’s not clear what the truthmaker could be, since in commanding you to do something, I am not describing how the world is, but rather, trying to get you to do something.
So here’s an idea I had last night: what if counterfactuals are a species of command? If counterfactual claims are really commands, then we wouldn’t need to find truthmakers for them, and we wouldn’t need to say possible worlds exist. So how could counterfactual claims be commands? Well, my idea is to think of them as commands to imagine or commands to conceive. When I say to someone “If I hadn’t stopped watering the plant it would still be alive”, what I am implicitly doing is giving instructions on how to imagine something. So the idea is that counterfactuals are implicit commands written for the imagination. When I start talking to someone about how things might be or how things might go, what I am doing is giving their brain instructions on how to make an imaginary construct similar to the one in my head. And in the same way that commanding someone to pick up a pen doesn’t need a truthmaker, neither does commanding or instructing someone to imagine something. So on this view counterfactual claims are not truth apt.
My account of modality is not quite a Quinean skepticism about modal concepts. I think modal concepts are quite fine in philosophy, since it just seems self-evident that I am in fact capable of imaging how the past might have gone, how the future might go, or even imagining whole other realities. But I don’t think that the ability for us to think modally require the inclusion of possible worlds into our metaphysics. I don’t think it’s quite right to say possible worlds exist. Processes of imagination exist in our heads. But the intentional objects of such processes don’t need to exist. The imagination doesn’t need truthmakers. It’s only true that I am imagining some way the world could have been, but the imaginary construct does not itself need truthmakers, for the same reason that commands don’t need truthmakers. And counterfactual claims are just implicit commands or instructions on how to guide your imagination.
So in everyday conversation if someone asks me to consider a counterfactual and I say in response “That’s true”, this need not commit me to any sort of possible worlds. It could just be a convenient shorthand for “Yes, it’s true that I am capable of imagining what you just instructed me to imagine”. But I do not think we need to invoke actual truthmakers to make sense of counterfactual language and thought. Let’s reserve truthmakers for things like cats on mats, not abstract imaginary constructs like possible worlds.
I’m quite open to the possibility that this idea of counterfactuals as commands is deeply confused because of some logical quirk about counterfactuals that I am not aware of. I’m also not sure if it’s an original idea or not. But I thought it was a neat idea, and it’s kind of inspired by some of the stuff I have been reading lately about language being first and foremost a tool, which has led me to think about all sorts of other cognitive activities as tools, including Reason. I think you could see counterfactual thinking as a kind of cognitive tool that enables humans to engage in activities that we would otherwise be incapable of.