What Is Randomness?
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The concept of randomness is central to many areas of scientific and mathematical study.
Despite the wide application of this concept to scientific experiment and explanation, no generally
accepted definition of randomness has yet been developed. The difficulty of constructing a theory
of randomness can be attributed in part to epistemological problems. The subjective experience of
unpredictability is closely connected to our understandings of randomness, but it is not a sufficient
condition for a definition, since a non-random event may be experienced as random if an observer is
constrained by epistemic limitations. The requirement, proposed by Antony Eagle, of an
intersubjective consensus on unpredictability in order to define an event as random, lessens but does
not resolve this difficulty. A definition of randomness as unpredictability is therefore useful in
considering the effects and applications of concepts of randomness, but problematic if we are
seeking to explain randomness in terms of possible ontological properties.
In spite of this, a theory that attempts to define randomness in terms of its intrinsic
properties rather than its observed effects is clearly necessary if randomness is to be seen as a
feature of reality, and not merely as a useful conceptual tool. This does not require that a theory of
randomness must apply to every sense in which we use the word. Rather, it is possible to
distinguish between varying uses of the term 'random' in differing contexts. Firstly, the qualities of
subjective experience which contribute to a belief that an event is 'random' may be analysed.
Secondly, the ways in which apparently random events might be demonstrated to have been
produced by non-random processes can be explored. A consideration of the relationship between
scientific knowledge and perceptions of randomness provides insight into the sorts of epistemic