The basic problem of a theory of truth approximation is defining when a theory is
“close to the truth” about some relevant domain. Existing accounts of truthlikeness or
verisimilitude address this problem, but are usually limited to the problem of approaching
a “deterministic” truth by means of deterministic theories.Ageneral theory of truth
approximation, however, should arguably cover also cases where either the relevant
theories, or “the truth”, or both, are “probabilistic” in nature. As a step forward in
this direction, we first present a general characterization of both deterministic and
probabilistic truth approximation; then, we introduce a new account of verisimilitude
which provides a simple formal framework to deal with such issue in a unified way.
The connections of our account with some other proposals in the literature are also
briefly discussed.