Universa Philosophia

Argumentation is the third mode of knowing, and the principal aim of the dialectical undertaking, for as Rhetoric forms the perfect orator, so Dialectic forms the disputant. Argumentation is therefore oratio explicans naturam rei, constans pluribus propositionibus, quarum ultima ex aliis sequi notatur. For example, Petrus est homo, ergo Petrus est animal; note that it is not an argumentation if that word ergo, or igitur, is lacking.

Argumentation is divided into syllogism, enthymeme, dilemma, example, and induction. Syllogismus in Greek is called in Latin ratiocinatio, or discursus: because the mind reasons by it, and runs from antecedent propositions to the conclusion, which is to discourse from one thing to another. This mode of knowing is the most perfect of all, by which the goal of disputation is concluded, without which nothing is accomplished. It is defined by Arist. 1. priorum c. 1. in almost these words: A syllogism is a mode of knowing in which, certain things being posited, something else necessarily follows. Those words certain things being posited signify the major and minor proposition; but those, something else follows, signify the conclusion, which follows the premises: but that, necessarily, signifies that the conclusion cannot not follow the premises: and this necessity is explained by these words igitur, ergo: wherefore they are called marks of inference: that is, signs of necessary consequence. For example, every man runs, Peter is a man: therefore Peter runs.

An enthymeme is an argumentation in which from one single proposition the conclusion follows. It differs from a syllogism because in the latter two antecedent propositions are posited, but in the former one. An enthymeme is called a truncated syllogism; understand this in speech: because we pass over one premise in silence: but in the mind there are no enthymemes, but perfect syllogisms; nor again does an enthymeme conclude unless it is completed into a syllogism: for example, every man runs: therefore Peter runs: that consequence is not good unless we add, Peter is a man: for if someone denies that Peter is a man, it concludes nothing.

A dilemma is a two-horned, or horned, argumentation in which two sides are posited so effectively that the respondent is necessarily caught, as if someone should propose two reasons, one of which must necessarily be conceded or denied: but from the concession or denial he is necessarily caught, as if someone should say that he is not lying, and another should argue thus: Either you went where I commanded, or you did not go: if you went; therefore you lie, when you say that you did not see John, who was there: if you did not go; therefore you lie, when you say that you went. Behold, from the concession and denial of either side, the respondent is convicted of lying. This argumentation can be formed into a syllogism and an enthymeme.

An example is an argument drawn from the deeds of others: for example, boys sometimes apply themselves to virtue: therefore men are also bound to apply themselves to virtue. This argumentation is more useful to the Rhetorician persuading morals than to the Dialectician binding the intellect.

Induction is an argumentation from a review of some singulars to gathering another conclusion. This argumentation, in order to have force, must touch all the singulars: for example: the earth has its proper place, likewise also the air, similarly also water and fire: therefore every element has its proper place: which argumentation is from all the dividing [members] to the divided. But if all the singulars are not reviewed, the argumentation is weak: just as if someone, having reviewed the individual men of Europe, should conclude, therefore every man is white, he would indeed conclude badly: because in Ethiopia there are black men. But in order that this argumentation be effective, it must be shown that there is no difference between the singulars reviewed and the others, as if someone should gather from the fires of Spain that every fire in Belgium is hot, it is necessary that he show that the account of Belgian and Spanish fire is the same.