I’m confused about what your goal is in making the kind of predictions you’re talking about. If, for example, you’re betting money on the outcome of your upcoming fencing bout, your estimate of how likely you are to win should include all hypotheses about possible paths to victory, and any of those paths should qualify as a validation of your prediction. If the decision you want to make is about something other than the outcome of the bout, e.g. how well you fence, then you should make a prediction about that instead.
In other words, the fencing bout looks like a toy example and I don’t understand what non-toy examples it’s supposed to be illustrating.
I’m confused about what your goal is in making the kind of predictions you’re talking about. If, for example, you’re betting money on the outcome of your upcoming fencing bout, your estimate of how likely you are to win should include all hypotheses about possible paths to victory, and any of those paths should qualify as a validation of your prediction. If the decision you want to make is about something other than the outcome of the bout, e.g. how well you fence, then you should make a prediction about that instead.
In other words, the fencing bout looks like a toy example and I don’t understand what non-toy examples it’s supposed to be illustrating.
The placebo effect is perhaps exemplary? Many interventions do work, but their mechanism isn’t the expected one, which can lead to poor decisions.