Quintilian Institutio Oratoria 7.2.22

[22] Further, such cases consist of comparison, which may be effected in different ways. For we may either compare our case in its entirety with that of our adversary, or we may compare individual arguments. The choice between these two methods can only be determined by the requirements of the case. For example, in the pro Vareno, Cicero, in dealing with the first charge, compares the individual arguments: for it would have been rash in connexion with the second charge to compare the position of a stranger with that of a mother. ¹ It is therefore best, if possible, to refute argument by individual argument: if, however, our individual arguments are weak, we shall try to secure success by comparison of case with case as a whole.