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*above*zero that is the threshold.

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lurflurf

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For example the probability of rolling ten cubic dice and having them all match is about 10^-7 it probably won't happen on your first try, but if you take several million attempts it might and after a billion attempts it will may have happened several times.

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abovezero that is the threshold.

The mathematical theory of probability assumes a contiguous set of probablities from ##0## to ##1##. There is no way to test whether this applies to the physical universe or whether probablities associated with physical processes are discrete in some way. Although, it's difficult to see why they would be discrete.

Unlike the other posters above, I would dispute that events with zero probability occur in real physical processes. This is a potential misapplication of probablity theory to physical processes.

For example, the simple mathematical statement: Let ##f(x) = \sin x##, defines a function infinite in extent. But, you can never physically have such an infinite sine function in reality. Likewise, "Let ##X## be a random variable uniformly distributed on ##[0, 1]## defines a mathematical object ##X##. But, such an ##X## cannot be conjured so easily in the real universe.

Likewise, "let E be an event with zero probability" seems to me a mathematical statement, conjuring a mathematical object, but cannot (necessarily) be shown to conjure a physical event.

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Stephen Tashi

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My original question had more to do with probability in physical events (chemistry, biology, geology, etc.) within the limits of our observable portion of whatever 'multiverse' might exist in reality.

There is no fixed relation between the probability of an event and the actual frequency with which the event happens. A fixed relation would contradict the concept of probability. For example, if you pick a number p and declare that an event with probability p cannot actually happen, then the probability of the event

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