This section had the purpose of introducing the so-called
Bayesian reasoning (that is, in reality, nothing more than just
probabilistic reasoning) with an aseptic, simple
example, that shows however the ingredients needed
to update our opinion on the light of new
At this point the role of the priors and
of the evidence in forming our
opinion about the hypotheses of interest should be clear.
Note also how I have used on purpose
several expressions to mean essentially the same thing,
expressions that involve words such as `probability', `belief',
`plausibility', `credibility', `confidence', and so on.