  This is a review of the issue of randomness in quantum mechanics, with
special emphasis on its ambiguity; for example, randomness has different
antipodal relationships to determinism, computability, and compressibility.
Following a (Wittgensteinian) philosophical discussion of randomness in
general, I argue that deterministic interpretations of quantum mechanics (like
Bohmian mechanics or 't Hooft's Cellular Automaton interpretation) are strictly
speaking incompatible with the Born rule. I also stress the role of outliers,
i.e. measurement outcomes that are not 1-random. Although these occur with low
(or even zero) probability, their very existence implies that the no-signaling
principle used in proofs of randomness of outcomes of quantum-mechanical
measurements (and of the safety of quantum cryptography) should be
reinterpreted statistically, like the second law of thermodynamics. In
appendices I discuss the Born rule and its status in both single and repeated
experiments, and review the notion of 1-randomness introduced by Kolmogorov,
Chaitin, Martin-Lo"f, Schnorr, and others.
