  This paper discusses the dual interpretation of the Jeffreys--Lindley's
paradox associated with Bayesian posterior probabilities and Bayes factors,
both as a differentiation between frequentist and Bayesian statistics and as a
pointer to the difficulty of using improper priors while testing. We stress the
considerable impact of this paradox on the foundations of both classical and
Bayesian statistics. While assessing existing resolutions of the paradox, we
focus on a critical viewpoint of the paradox discussed by Spanos (2013) in
Philosophy of Science.
