_ratione, doctrina_ (opp. _usu_) _aliquid cognitum habere_—to have a
theoretical knowledge of a thing.
_ad artem, ad rationem revocare aliquid_ (De Or. 2. 11. 44)—to reduce
a thing to its theoretical principles; to apply theory to a thing.
_doctrinam ad usum adiungere_—to combine theory with practice.
_in rebus atque in usu versatum esse_—to have had practical experience.
_usu_[1] _praeditum esse_—to possess experience.
_magnum usum in aliqua re habere_—to have had great experience in a
thing.
_multarum rerum usus_—varied, manifold experience.
_usu rerum (vitae, vitae communis) edocti sumus_—we know from
experience.
_experti scimus, didicimus_—we know from experience.
_usu cognitum habemus_—we know from experience.
_res ipsa, usus rerum (cotidie) docet_—everyday experience tells us
this.
_(rerum) imperitum esse_—to have had no experience of the world.
_multa acerba expertus est_[2]—he has had many painful experiences.
_usus me docuit_—experience has taught me.
[1] Not _experientia_, which in classical prose means attempt, proof.
[2] _experiri_ is only used of personal experience.