233. Quod populus postremum jussit, id jus ratum esto. That which a people has last ordained shall be the established law.
(See Steph. Comm. I. p. 43, and Max. No. 137.)
* 234. Quod turpi ex causâ promissum est, non valet. An immoral (illegal or base) consideration will not support a promise (i.e., a contract).
So also one founded on an impossible or purely moral consideration.
(See Chitty on Contracts, 16th ed. p. 4, and Maxs. Nos. 80 and 82.)
* 235. Quoties in verbis nulla est ambiguitas, ibi nulla expositio contra verba fienda est. When there is no ambiguity in the language of an instrument, no interpretation is to be made contrary to the words.
It is a rule that parol evidence contrary to the express written language itself is excluded, and the instrument itself is the only criterion of the intention of the parties. Parol evidence may be admissible to explain, but not to contradict or override, the express written contents of an instrument.
(See Chitty on Contracts, 16th ed. p. 116.)
236. Quoties idem sermo duas sententias exprimit ea potissimum accipiatur, quae rei gerendae aptior est. When the same expression carries two meanings, that shall be preferred which is the more fitted to elucidate the subject-matter.
This is one of the numerous rules for the construction of legal documents. (See Max. No. 26.)