Institutio Oratoria

while there can be no proof except such as is derived from things consequent or things opposite, which must be sought for either in the time preceding, contemporaneous with or subsequent to the alleged fact, nor can any single thing be proved save by reference to something else which must be greater, less than or equal to it.

As regards arguments, they may be found either in the questions raised by the case, which may be considered by themselves quite apart from any connexion with individual

Again there are four forms of proof. First, we may argue that, because one thing is, another thing is not; as It is day and therefore not night. Secondly, we may argue that, because one thing is, another thing is; as The sun is risen, thereit is day. Thirdly, it may be argued that because one thing is not, another thing is; as It is not night, therefore it is day. Finally, it may be argued that, because one thing is not, another thing is not; as He is not a reasoning being, therefore he is not a man. These general remarks will suffice by way of introduction and I will now proceed to details.

Every artificial proof consists either of indications, arguments or examples. I am well aware that many consider indications to form part of the arguments. My reasons for distinguishing them are twofold. In the first place indications as a rule come under the head of inartificial proofs: for a bloodstained garment, a shriek, a dark blotch and the like are all evidence analogous to documentary or oral evidence and rumours; they are not discovered by the orator, but are given him with the case itself.

My second reason was that indications, if indubitable, are not arguments, since they leave no room for question, while arguments are only possible in controversial matters. If on the other hand they are doubtful, they are not arguments, but require arguments to support them.