Thank you for giving me feedback about how my question was ambiguous. Sorry for the confusion, and I reformulated my question.
Reformulation: Let's say a black box is giving me a real number every second in a truly random way.
By truly random, I mean that there is no way for one to predict what number will come next.
But I don't yet know if the black box is giving me numbers in a random way or in some way with a pattern.
Is there any way for me to prove that the black box is giving me numbers in a truly random way?
Eric's numbers are random because he is affected by quantum physics. His numbers are also pseudorandom in the sense that there is an internal biological (neurological) process by which he is selecting numbers, but that process is unknown.
– Myridium May 26 '21 at 19:34