In M1, vision depends on light, which is blocked by eyelids. Therefore in M1, we predict that closing my eyes leads to a blackout of vision. In M2, vision depends on something else, which is not blocked by eyelids. Therefore in M2, we predict that closing my eyes does not lead to a blackout of vision.
At some later time, an event occurs in M1: specifically, I close my eyelids. At the same time, I have a blackout of vision. This increases my confidence in the predictive power of M1.
So far, so good.
At the same time, an identical event-pair occurs in M2: I close my eyes and my vision blacks out. This decreases my confidence in the predictive power of M2.
If I’ve understood you correctly, both the realist and the instrumentalist account of all of the above is “there are two models, M1 and M2, the same events occur in both, and as a consequence of those events we decide M1 is more accurate than M2.”
The realist account goes on to say “the reason the same events occur in both models is because they are both fed by the same set of externally realized events, which exist outside of either model.” The instrumentalist account, IIUC, says “the reason the same events occur in both models is not worth discussing; they just do.”
OK. So, say I have two models, M1 and M2.
In M1, vision depends on light, which is blocked by eyelids. Therefore in M1, we predict that closing my eyes leads to a blackout of vision. In M2, vision depends on something else, which is not blocked by eyelids. Therefore in M2, we predict that closing my eyes does not lead to a blackout of vision.
At some later time, an event occurs in M1: specifically, I close my eyelids. At the same time, I have a blackout of vision. This increases my confidence in the predictive power of M1.
So far, so good.
At the same time, an identical event-pair occurs in M2: I close my eyes and my vision blacks out. This decreases my confidence in the predictive power of M2.
If I’ve understood you correctly, both the realist and the instrumentalist account of all of the above is “there are two models, M1 and M2, the same events occur in both, and as a consequence of those events we decide M1 is more accurate than M2.”
The realist account goes on to say “the reason the same events occur in both models is because they are both fed by the same set of externally realized events, which exist outside of either model.” The instrumentalist account, IIUC, says “the reason the same events occur in both models is not worth discussing; they just do.”
Is that right?