Nevertheless, the disputant ought as much as possible to avoid the universal in introducing syllogisms; and it is also requisite always to observe whether the arguments are conversant with things common, for all particular are conversant with universal, and the demonstration of the universal is inherent in that which is particular, because nothing can be syllogistically concluded without universals.
We should assign the exercise of inductive arguments to a young man, but of syllogistic ones to a practised man; we should also endeavour to assume propositions from those who are skilful in syllogisms, but comparisons from the inductive, for in these each are exercised. In short, from dialectic exercise, we must endeavour to draw either a syllogism about something, or a solution, or a proposition, or an objection, or whether any one has rightly or not rightly questioned, whether himself or another, and about what each is. For from these the power (of discussion arises), and exercise is on account of power, especially in propositions and objections; since, in short, he is the dialectician, who is ready to propose and to object; but to propose is to make many things one, (since it is requisite for that to be assumed in the whole, to which the argument belongs,) but to object (is to make) one many, since a man either divides or subverts, partly admitting, and partly denying the proposition.
It is requisite still, not to dispute with every one, nor to exercise ourselves against any casual person, for it is necessary to employ bad arguments against some, since against him, who altogether tries to seem to elude us, it is just indeed, by all means, to try to draw a conclusion, yet it is not becoming. Wherefore, it is not proper readily to engage with casual persons, since depraved disputation will necessarily occur; for even those who practise themselves, cannot forbear disputing contentiously.
