This seems to me like an extended case of a BinomiaL ProbabilitY DistributioN;
the outcomes are either success or failure, so I can see how people might argue that each has 50% happening.
Let n=# of trials, and s=the successful/favorable outcome (the one we want). By definition, the "probability" of 's' equals the frequency of 's' in n#trials, as n approaches infinity (we get more and more trials). By law of large numbers, the probability of 's' approaches the theoretical probability of 's', and thus we may not always get the 50% probability for success or failure, if, for example, there are 3 ways to succeed but 7 ways to fail.
The 50% theory here may also be just a case where, to simulate each outcome (success/failure), we flip a penny. The theoretical probability of success may be, for example, 3/7, but we may get 50% if we flip a penny to determine success/failure---rather than a 10-sided die with 3 faces for success and 7 for failure.
We can argue 50% probability for outcomes which either happen or don't happen, but only if each such outcome has equal likelihood of occurring, because 50%chance success means 50%chace failure as well.
In my opinion, by philosophy, we do not "know" exactly what each subsequent outcome will be in the course of an experiment (with binomial outcomes), for example; we can only guess and make calculations as to which is more "probable". However, theoretical probability cannot 100% predict the outcome of the next trial (it can guess, but not with 100% accuracy!) (It seems nature takes its own course ). Because we are not completely "sure" of outcomes in upcoming trials, people might argue that we cannot really use theoretical probability at all to exactly predict the next outcome, and only assume that just 'cause there are only two outcomes with an uncertain "exact" probability, we cannot use theoretical probability at all (because it's not exact!)! Thus, we are left only to assume that each outcome has 50% occurring, because we are "equally-unsure" of the exact chance of failure and the exact chance of success!
(Well, what do you guys think

? I understand the viewpoint of people who argue 50%-50%chance theory (or whatever it is called), but i don't think "probability" is really the best word to describe this position)
CronoSpark said:
It might change... that is if we get a "super" computer that can "instantly" compute every single aspect in the universe... and then we can see what other factors are able to change our probability.
But then i think...suppose we could develop such a computer! =>if we analyze every possible variable...down to the smallest particle..."exactly"----would it actually turn out that, down to this smallest level of influence...the probability of influence will actually be 50%-50% (either "influence" or "no influence" binomial outcome)? (by "smallest influential variable"...i mean even the "stuff" that exist in the beginning of time that influenced..then influenced...then influenced...(well, you get the point)..everything up until present)? (to make things easier, assuming that only a single variable is under examination...which influenced everything else, and was not influenced at all by anything which came before it---)
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You know the saying that goes, "We do know anything for certain..."; well, i wonder if this might apply to this 50%-50% probability idea. According to this saying (and
not taking into account probability, which is uncertain!), can we be certain at least that we have exactly equal uncertainty for any event? If so, then binomially, then the 50%-50% theory makes some sense. The central idea here is that we are either 100% certain about the event, or uncertain (i.e., 0% certain) about it; what do YOU think?
I think this should be in the philosophy post/section.