Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
But although such an indication may not amount to proof in itself, yet it may be produced as evidence in conjunction with other indications, such for instance as the fact that the man with the bloodstain was the enemy of the murdered man, had threatened him previously or was in the same place with him. Add the indication in question to these, and what was previously only a suspicion may become a certainty.
On the other hand there are indications which may be made to serve either party, such as livid spots, swellings which may be regarded as symptoms either of poisoning or of bad health, or a wound in the breast which may be treated as a proof of murder or of suicide. The force of such indications depends on the amount of extraneous support which they receive.
Hermagoras would include among such indications as do not involve a necessary conclusion, an
Atalanta cannot be a virgin, as she has been roaming the woods in the company of young men.If we accept this view, I fear that we shall come to treat all inferences from a fact as indications. None the less such arguments are in practice treated exactly as if they were indications.