I keep wanting to think that David Chalmers, in a brilliant insight (zombie argument), figured out precisely what’s wrong with modal logic instead of proving anything about consciousness. But without being able to make that stick, perhaps he did indeed disprove physicalism. I just came across this post from last year on Reality Conditions discussion “possibility”.
Dennett is cited saying,
Smiling demons, cow-sharks, Blockheads, and Swampmen are all, some philosophers think, logically possible, even if they are not nomologically possible, and these philosophers think this is important. I do not.
And there is some discussion on how science would be skeptical of distinquishing between metaphysical and nomological necessity.
I’d like to say that logical possibility, as entailed by conceivability doesn’t see far enough down the road and what might at first seem logically possible might not be once more facts are on the table. But what other thought roads besides zombies and swampmen might such a position seal off?
What about the Flying Speghetti Monster? Surely he isn’t nomologically possible. Are we inclined to say that in some circumstances, depending on what our point is, we can rely on mere logical possibility? In this case, we might backpedal and say that we can make the same point with Russell’s teapot which isn’t quite so fanciful. But is Russell’s teapot nomologically possible? It seems physically possible, but even given the contingency of the laws of nature, it probably isn’t (or wasn’t) since it had to get into orbit by real, physical means.
But to back off further would amount to destroying the thought experiment as the whole point is to trade credulity on conceivability. Even in a reductio ad absurdum, we must bank on the possibility of our wacky scenario.
And what about innocent counterfactuals? Yes, I could have spared the two Hell’s Angels bikers in the bar last night, but I was really mad about their opinions on dual-sports. My brain had to be in the state it was. The more facts revealed on the incident, when understood all the way through, pretty much lock the events of last night into exactly what they were.
In everyday scenarios we back off on counterfactuals all the time. Yeah, the guy didn’t have to thrust the knife for the 15th time – ohhh, he wasn’t on his medications? And we also, depending on our vested interests, can be either extraordinarily sympathetic to or skeptical of logical possibilities.
I don’t know what the answer is, just throwing it out.