Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
These four schemes or forms of action which I then called general bases fall into two classes as I have
Legal questions necessarily have a larger number of species, since there are many laws and a variety of forms. In the case of one law we rely on the letter, in others on the spirit. Some laws we force to serve our turn, when we can find no law to support our case, others we compare with one another, and on others we put some novel interpretation.
Thus from these three bases we get three resemblances of bases: sometimes simple, sometimes complex, but all having a character of their own, as, for instance, when questions of the letter of the law and its intention are involved, for these clearly come under conjecture or quality; or again where the syllogism is involved, for this is specially connected with quality; or where contradictory laws are involved, for these are on the same footing as the letter of the law and intention; or yet again in cases of ambiguity, which is always resolved by conjecture.