Exactly. So the question becomes what qualifies as an equivalent macro state. In the computations relating to, say, the formation of life, that is very far from being clear. For questions related to the structure of the universe, it is even less so.But if a huge multitude of micro states give an identical macro state, then the probability of that macro state emerging is very, very, high.
So, for example, many calculations ask what the probability of some specific protein forming would be. That amounts to calculating a micro state. The appropriate macro state is finding the probability that some protein doing a similar job would be formed. Even this is usually not the correct question, though.
A better question is what the probability is that a system of interacting proteins and nucleus acids will form that allows for reproduction. The difficulty is that we have absolutely no idea how to even approach that question.
So, there are at least two issues: one is what qualifies two micro states as equivalent macro states. The other is a lack of a good probability measure for determining probabilities.
Understood. But we need to be sure that any calculation done is for a reasonable macro state and not for a micro state. So, calculation of specific results is NOT appropriate. Instead, calculation of some result similar is the appropriate one.How high is the probability of a billion grains of sand being randomly arranged in such a way as to yield a sandy beach? Compare that with the probability of all the matter and energy in the universe being randomly arranged in such a state as to initiate the Big Bang.
And even that assumes there is an appropriate probability measure for determining probabilities. In many situations that is not the case.