§557. CLAUSES WITH QUīN AND QUōMINUS

The original meaning of quīn is how not? why not? ( quī-nē), and when used with the Indicative or (rarely) with the Subjunctive it regularly implies a general negative. Thus, quīn ego hōc rogem? why should n't I ask this? implies that there is no reason for not asking. The implied negative was then expressed in a main clause, like nūlla causa est or fierī nōn potest. Hence come the various dependent constructions introduced by quīn.

Quōminus is really a phrase ( quō minus), and the dependent constructions which it introduces have their origin in the relative clause of purpose with quō and a comparative (see § 531. a).