Thanks, so to get back to the original question of how to describe the different effects of divergence and convergence in the context of MW, here’s how it’s seeming to me. (The terminology is probably in need of refinement).
Considering this in terms of the LW-preferred Many Worlds interpretation of quantum mechanics, exact “prediction” is possible in principle but the prediction is of the indexical uncertainty of an array of outcomes. (The indexical uncertainty governs the probability of a particular outcome if one is considered at random.) Whether a process is convergent or divergent on a macro scale makes no difference to the number of states that formally need to be included in the distribution of possible outcomes. However, in the convergent process the cases become so similar that there appears to be only one outcome at the macro scale; whereas in a divergent process the “density of probability” (in the above sense) becomes so vanishingly small for some states that at a macro scale the outcomes appear to split into separate branches. (They have become decoherent.) Any one such branch appears to an observer within that branch to be the only outcome, and so such an observer could not have known what to “expect”—only the probability distribution of what to expect. This can be described as a condition of subjective unpredictability, in the sense that there is no subjective expectation that can be formed before the divergent process which can be reliably expected to coincident with observation after the process.
Thanks, so to get back to the original question of how to describe the different effects of divergence and convergence in the context of MW, here’s how it’s seeming to me. (The terminology is probably in need of refinement).
Considering this in terms of the LW-preferred Many Worlds interpretation of quantum mechanics, exact “prediction” is possible in principle but the prediction is of the indexical uncertainty of an array of outcomes. (The indexical uncertainty governs the probability of a particular outcome if one is considered at random.) Whether a process is convergent or divergent on a macro scale makes no difference to the number of states that formally need to be included in the distribution of possible outcomes. However, in the convergent process the cases become so similar that there appears to be only one outcome at the macro scale; whereas in a divergent process the “density of probability” (in the above sense) becomes so vanishingly small for some states that at a macro scale the outcomes appear to split into separate branches. (They have become decoherent.) Any one such branch appears to an observer within that branch to be the only outcome, and so such an observer could not have known what to “expect”—only the probability distribution of what to expect. This can be described as a condition of subjective unpredictability, in the sense that there is no subjective expectation that can be formed before the divergent process which can be reliably expected to coincident with observation after the process.
With the caveat that I’m not a physicist, and don’t understand much of the math involved—yes, this seems to be correct.
Though note that quantum physics operates on phase space; if two outcomes are the same in every respect, then they really are the same outcome.