Greek Texts & Translations

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.

According to them some presentations are data of sense and others are not : the former are the impressions conveyed through one or more sense-organs ; while the latter, which are not data of sense, are those received through the mind itself, as is the case with incorporeal things and all the other presentations which are received by reason. Of sensuous impressions some are from real objects and are accompanied by yielding and assent on our part. But there are also presentations that are appearances and no more, purporting, as it were, to come from real objects.

Another division of presentations is into rational and irrational, the former being those of rational creatures, the latter those of the irrational. Those which are rational are processes of thought, while those which are irrational have no name. Again, some of our impressions are scientific, others unscientific : at all events a statue is viewed in a totally different way by the trained eye of a sculptor and by an ordinary man.

The Stoics apply the term sense or sensation ( αἴσθησις) to three things: (1) the current passing from the principal part of the soul to the senses, (2) apprehension by means of the senses, (3) the apparatus of the sense-organs, in which some persons are deficient. Moreover, the activity of the sense-organs is itself also called sensation. According to them it is by sense that we apprehend black and white, rough and smooth, whereas it is by reason that we apprehend the conclusions of demonstration, for instance the existence of gods and their providence. General notions, indeed, are gained in the following ways : some by direct contact, some by resemblance, some by analogy, some by transposition, some by composition, and some by contrariety.

By incidence or direct contact have come our notions of sensible things ; by resemblance notions whose origin is something before us, as the notion of Socrates which we get from his bust ; while under notions derived from analogy come those which we get (1) by way of enlargement, like that of Tityos or the Cyclops, or (2) by way of diminution, like that of the Pygmy. And thus, too, the centre of the earth was originally conceived on the analogy of smaller spheres. Of notions obtained by transposition creatures with eyes on the chest would be an instance, while the centaur exemplifies those reached by composition, and death those due to contrariety. Furthermore, there are notions which imply a sort of transition to the realm of the imperceptible : such are those of space and of the meaning of terms. The notions of justice and goodness come by nature. Again, privation originates notions ; for instance, that of the man without hands. Such are their tenets concerning presentation, sensation, and thought.

The standard of truth they declare to be the apprehending presentation, i.e. that which comes from a real object - according to Chrysippus in the twelfth book of his Physics and to Antipater and Apollodorus. Boëthus, on the other hand, admits a plurality of standards, namely intelligence, senseperception, appetency, and knowledge ; while Chrysippus in the first book of his Exposition of Doctrine contradicts himself and declares that sensation and preconception are the only standards, preconception being a general notion which comes by the gift of nature (an innate conception of universals or general concepts). Again, certain others of the older Stoics make Right Reason the standard ; so also does Posidonius in his treatise On the Standard.