Greek Texts & Translations

Dialectic (they hold) falls under two heads : subjects of discourse and language. And the subjects fall under the following headings : presentations ^note and the various products to which they give rise, propositions enunciated and their constituent subjects and predicates, and similar terms whether direct or reversed, genera and species, arguments too, moods, syllogisms and fallacies whether due to the subject matter or to the language ; 7.1.44 these including both false and true and negative arguments, sorites and the like, whether defective, insoluble, or conclusive, and the fallacies known as the Veiled, or Horned, No man, and The Mowers.

The second main head mentioned above as belonging to Dialectic is that of language, wherein are included written language and the parts of speech, with a discussion of errors in syntax and in single words, poetical diction, verbal ambiguities, euphony and music, and according to some writers chapters on terms, divisions, and style.

The study of syllogisms they declare to be of the greatest service, as showing us what is capable of yielding demonstration ; and this contributes much to the formation of correct judgements, and their arrangement and retention in memory give a scientific character to our conception of things.

An argument is in itself a whole containing premisses and conclusion, and an inference (or syllogism) is an inferential argument composed of these. Demonstration is an argument inferring by means of what is better apprehended something less clearly apprehended.

A presentation (or mental impression) is an imprint on the soul : the name having been appropriately borrowed from the imprint made by the seal upon the wax. 7.1.46 There are two species of presentation, the one apprehending a real object, the other not. The former, which they take to be the test of reality, is defined as that which proceeds from a real object, agrees with that object itself, and has been imprinted seal-fashion and stamped upon the mind : the latter, or non-apprehending, that which does not proceed from any real object, or, if it does, fails to agree with the reality itself, not being clear or distinct.

Dialectic, they said, is indispensable and is itself a virtue, embracing other particular virtues under it. ^note Freedom from precipitancy is a knowledge when to give or withhold the mind's assent to impressions. By wariness they mean a strong presumption against what at the moment seems probable, so as not to be taken in by it. 7.1.47 Irrefutability is strength in argument so as not to be brought over by it to the opposite side. Earnestness (or absence of frivolity) is a habit of referring presentations to right reason. Knowledge itself they define either as unerring apprehension or as a habit or state which in reception of presentations cannot be shaken by argument. Without the study of dialectic, they say, the wise man cannot guard himself in argument so as never to fall ; for it enables him to distinguish between truth and falsehood, and to discriminate what is merely plausible and what is ambiguously expressed, and without it he cannot methodically put questions and give answers.

Overhastiness in assertion affects the actual course of events, so that, unless we have our perceptions well trained, we are liable to fall into unseemly conduct and heedlessness ; and in no other way will the wise man approve himself acute, nimblewitted, and generally skilful in argument ; for it belongs to the same person to converse well and to argue well, to put questions to the purpose and to respond to the questions put ; and all these qualifications are qualifications belonging to the skilled dialectician. Such is, summarily stated, the substance of their logical teaching. And in order to give it also in detail, ^note let me now cite as much of it as comes within the scope of their introductory handbook. I will quote verbatim what Diocles the Magnesian says in his Synopsis of Philosophers. These are his words :

"The Stoics agree to put in the forefront the doctrine of presentation and sensation, inasmuch as the standard by which the truth of things is tested is generically a presentation, and again the theory of assent and that of apprehension and thought, which precedes all the rest, cannot be stated apart from presentation. For presentation comes first ; then thought, which is capable of expressing itself, puts into the form of a proposition that which the subject receives from a presentation."

There is a difference between the process and the outcome of presentation. The latter is a semblance in the mind such as may occur in sleep, while the former is the act of imprinting something on the soul, that is a process of change, as is set forth by Chrysippus in the second book of his treatise Of the Soul (De anima). For, says he, we must not take "impression" in the literal sense of the stamp of a seal, because it is impossible to suppose that a number of such impressions should be in one and the same spot at one and the same time. The presentation meant is that which comes from a real object, agrees with that object, and has been stamped, imprinted and pressed seal-fashion on the soul, as would not be the case if it came from an unreal object.