  The sequence of the primes $p$ for which a variety over $\mathbb{Q}$ has no
$p$-adic point plays a fundamental role in arithmetic geometry. This sequence
is deterministic, however, we prove that if we choose a typical variety from a
family then the sequence has random behavior.
  We furthermore prove that this behavior is modelled by a random walk in
Brownian motion. This has several consequences, one of them being the
description of the finer properties of the distribution of the primes in this
sequence via the Feynman-Kac formula.
