Even before the water=H2O discovery is was conceptually coherent/conceivable that electrolysing water yields hydrogen.
But lots of other things were conceivable before the discovery. The narrowing is that, in terms of the correct explanation, the possibility that you get sodium and chlorine is no longer tenable .
And it was and is conceivable to levitate a frog as there is no contradiction in this idea.
Yet the average person would say it isn’t possible.
Conceivability isn’t one thing.
Philosophers treat conceivability as a strict lack of contradiction, ordinary people make a judgement based on a bunch of things including background beliefs in physics.
Conceivability isn’t one thing even in one person. One person can make a judgement in terms of pure non contradiction, or in terms of common sense assumptions, or in terms of some sophisticated scientific theory , if they know it.
“Yet the average person would say it isn’t possible.”
I’d distinguish conceivability from possibility. In the case of possibility there are many types: logical possibility (no logical contradiction), broad logical possibility (no conceptual incoherence), nomological possibility, physical possibility, etc. Most people would probably agree that levitating frogs are logically possible, broadly logically possible, but not physically or nomologically possible as this would contradict the laws of physics.
It’s less clear to me that there are many different types of conceivability. But even if they are: the type I care about in the post above is something like “forming a mental model of”.
“But lots of other things were conceivable before the discovery. The narrowing is that, in terms of the correct explanation, the possibility that you get sodium and chlorine is no longer tenable .”
Most people would probably agree that levitating frogs are logically possible, broadly logically possible, but not physically or nomologically possible as this would contradict the laws of physic
Most people would make a snap judgement , and not have any idea about the different kinds of conceivability and possibility.
But lots of other things were conceivable before the discovery. The narrowing is that, in terms of the correct explanation, the possibility that you get sodium and chlorine is no longer tenable .
Yet the average person would say it isn’t possible.
Conceivability isn’t one thing.
Philosophers treat conceivability as a strict lack of contradiction, ordinary people make a judgement based on a bunch of things including background beliefs in physics.
Conceivability isn’t one thing even in one person. One person can make a judgement in terms of pure non contradiction, or in terms of common sense assumptions, or in terms of some sophisticated scientific theory , if they know it.
“Yet the average person would say it isn’t possible.”
I’d distinguish conceivability from possibility. In the case of possibility there are many types: logical possibility (no logical contradiction), broad logical possibility (no conceptual incoherence), nomological possibility, physical possibility, etc. Most people would probably agree that levitating frogs are logically possible, broadly logically possible, but not physically or nomologically possible as this would contradict the laws of physics.
It’s less clear to me that there are many different types of conceivability. But even if they are: the type I care about in the post above is something like “forming a mental model of”.
“But lots of other things were conceivable before the discovery. The narrowing is that, in terms of the correct explanation, the possibility that you get sodium and chlorine is no longer tenable .”
I see, that’s a helpful example.
Most people would make a snap judgement , and not have any idea about the different kinds of conceivability and possibility.