Complexity heuristics possibly work to some extent here. If A is a hypothesis of comparable complexity to B, then you at least have some basis for assigning them comparable prior probabilities.
If A can be conveniently split into A1 and A2, then the child hypotheses are often more complex than A in that they each require some additional property on top of A. This isn’t always the case, but in the exceptional cases it’s likely more useful to consider one or both of the child hypotheses to be “primary” instead of A.
This is all very rough, since complexity is usually only defined up to some constant and is relative to some sort of specification model, but it’s something that isn’t necessarily contingent on observations of the world. If you’re an entity that is considering probabilities and hypotheses at all, the concept of measuring complexity is likely already accessible to you.
Complexity heuristics possibly work to some extent here. If A is a hypothesis of comparable complexity to B, then you at least have some basis for assigning them comparable prior probabilities.
If A can be conveniently split into A1 and A2, then the child hypotheses are often more complex than A in that they each require some additional property on top of A. This isn’t always the case, but in the exceptional cases it’s likely more useful to consider one or both of the child hypotheses to be “primary” instead of A.
This is all very rough, since complexity is usually only defined up to some constant and is relative to some sort of specification model, but it’s something that isn’t necessarily contingent on observations of the world. If you’re an entity that is considering probabilities and hypotheses at all, the concept of measuring complexity is likely already accessible to you.
This is a good point. I neglected to address this possibility.