_ratio; disciplina, ratio et disciplina; ars_—system.
_ad artem redigere aliquid_—to systematise.
_ad rationem, ad artem et praecepta revocare aliquid_ (De Or. 1.
41)—to systematise.
_arte conclusum esse_—to have been reduced to a system.
_ratio et doctrina_—systematic, methodical knowledge.
_artificio et via tradere aliquid_—to give a scientific explanation of
a thing.
_artificiose redigere aliquid_—to treat with scientific exactness; to
classify.
_ad rationis praecepta accommodare aliquid_—to treat with scientific
exactness; to classify.
_totam rationem evertere_ (pass. _iacet tota ratio_)—to upset the
whole system.
_ratione et via, via et ratione progredi, disputare_ (Or. 33. 116)—to
proceed, carry on a discussion logically.
_novam rationem ingredi_—to enter on a new method.
_a certa ratione proficisci_—to be based on a sound principle.
_a falsis principiis proficisci_—to start from false premises.
_ad philosophorum_ or _philosophandi rationes revocare aliquid_—to
deal with a subject on scientific principles.
_perpetuitas et constantia_ (Tusc. 5. 10. 31)—logical consistency.