This interpretive hypothesis is reinforced by the way in which Aristo-tle (16b.19ff) wonders whether verbs as to be or not to be are signs of the existence of the thing. His line of thought is the following: (a) outside the sentence, no verb can state that something really exists or actually does something; (b) verbs can perform this function only in a complete assertive sentence; (c) not even to be or not to be, uttered in isolation, assert the existence of something; (d) however, when they are inserted into a sentence, they are signs (or, as some translators interpret, «they are indicative of the fact») that the existence of something is asserted. Such an interpretation is confirmed by what Aristotle has previously said (16b. 5ff), namely, that a verb is always the sign (or that it is indicative of the fact) that something is said or asserted of something.
Aquinas, in his commentary on De Interpretatione, lucidly analyzes this passage. He ex-cludes, however, a reading that could sound very attractive to a contem-porary mind, that is, that the verb is the signifier of which a predication is the signified, or that the sentence that contains the verb is the vehicle of an assertive proposition. On the contrary, Aquinas chooses a more commonsensical reading: the presence of the verb within a sentence is the proof, the symptom that this sentence asserts the existence of some-thing by actually predicating something of something.
Thus we are entitled to understand that, when Aristotle incidentally uses the term sign for words, he is simply stressing that even words can be taken as symptoms. He is not equating linguistic symbols with natu-ral signs. He is only saying that sometimes symbols can be taken as proofs. But symbols are different from other natural signs because, when they function primarily as symbols (independently of their possible use as proofs), they are not based on the model of inference but on the model of equivalence. Aristotle was in fact the first to insist that linguistic terms are equivalent to their definitions and that word and definition are fully reciprocable (as we shall see in Chapter 2 of this book).
The sign makes its appearance in the Rhetoric, where the enthymemes are said to be derived from verisimilitudes (eikota: είκότα) and from signs (semeîa). But the signs are divided into two logically well-differential categories. The first type of sign has a specific name, tekmerion, in the sense of ‘evidence’. We can translate it as necessary sign; if one has a fever, then one is ill; if a woman has milk, then she has given birth. The necessary sign can be translated into the universal statement ‘all those who have a fever are ill9. It must be noted that this statement does not establish a relation of equivalence (biconditional).
One can be ill (for instance, with an ulcer) without having a fever. The second type of sign, says Aristotle, does not have a specific name. We could call it a weak sign: if one has difficulty in breathing, then one has a fever. The conclusion is obviously only probable, because the dif-ficulty in breathing could be caused by excessive physical exercise. Transformed into a premise, the sign would only give a particular affirmative: ‘some people have difficulty in breathing and they have a fever’ (the logical form is one of conjunction rather than implication). The weak sign is such just because the necessary sign does not establish an equivalence. A weak sign can be produced by converting the uni-versal affirmative — into which the necessary sign has been turned — into a particular affirmative. The subordinate of ‘all those who have a fever are ill’ yields in terms of a logical square, ‘there are some people who are ill and who have a fever’, which in fact is a weak sign and permits —at most—an induction.
Actually, Aristotle is uneasy with these different types of signs. He knows the apodictic syllogism, but he does not know, at least not with theoretical clarity, the hypothetical syllogism, that is, the p q form which will be the glory of the Stoics. For this reason Aristotle traces argumentative schemes, but he does not dwell on their logical form.
1.7. The Stoics
The Stoics also (from what can be gathered of their quite complex semiotics) do not seem to integrate clearly their theory of language and their theory of signs. In verbal language, they distinguish clearly be-tween sêmaînon (σημαϊνον: expression), sëmainomenon (σημαινομενον\ content), and tynchanon (τυyχavov: referent). They seem to reproduce the triad suggested by Plato and Aristotle, but they rework it with a theoretical subtlety lacking in many of those who have today reinvented such a semantic triangle.
The Stoics analyze the multiple articulation of the expression and distinguish the simple sound emitted by the larynx and the articulatory muscles (an as-yet-inarticulate sound) from the articulate linguistic element and from the actual word which exists only insofar as it is related or relatable to a content. Such a model functions as if to say, with Saussure, that the linguistic sign is a twofold entity.
Augustine, in the wake of the Stoics, will call dictio that verbum vocis which forts sonat, being at the same time perceived and recognized because it is related to a verbum mentis or cordis. The Stoics thought that the barbarians were able to per-ceive the physical sound, but unable to recognize it as a word. This happened, not because the barbarians lacked the corresponding mental image, but because they did not know the correlational rule. In this respect, the Stoics go much further than their predecessors and discover the provisional and unstable nature of the sign-function (the same con-tent can make up a word with an expression of a different language).
With Stoics, the content ceases to be, as it was with their predeces-sors, an affection of the soul, a mental image, a perception, a thought or an idea. It is neither an idea in the Platonic sense, since the Stoics have a materialistic metaphysics, nor an idea in the psychological sense, since even in this case the content would be a body, a physical fact, an altera-tion of the soul (which is also a body), a seal impressed upon the mind. Instead, the Stoics suggest that the content is an ‘incorporeal’.
The void, location, and time are incorporeals, as well as spatial rela-tions, chronological sequences, actions, and events. The incorporeals are not things, they are states, modes of being. Geometric surfaces and the thinnest section of the cone are incorporeals. Incorporeals are entia ra-tionis insofar as every ens rationis is a relationship, a way of looking at things. Among the incorporeals the Stoics put the lekton (λεκτоν), which has been translated as ‘expressible’, dictum, or dicible. The lekton is a semiotic category. The fact of Dion walking is, in the moment of its expression, a lekton.
The first problem is the relationship between the sêmainomenon and the lekton. If ‘Dion walks’ is a proposition (and, therefore, an incor-poreal), are ‘Dion’ and ‘walks’ also incorporeals? Sextus Empiricus iden-tifies semainomenon and lekton as synonyms (Adv. Math. 8.12); however, the solution appears to be more complex. The Stoics talk of complete and incomplete lekta. The complete lekton is a proposition, whereas the incomplete lekta are parts, pieces of propositions which are combined into the proposition through a series of syntactical links. The subject and the predicate are listed among the incomplete lekta.
They appear to be grammatical and lexical categories and, therefore, categories of the ex-pression, but in point of fact they are categories of the content. The subject (which is the usual translation of the word ptosis, πτωσις) repre-sents the uppermost example of case, because the attention devoted to assertive propositions caused the subject to be seen as the case par excellence. But the case is not the inflection form (a grammatical category that expresses the case). Rather, it is the expressed or expressible content. Today we would say that it is a pure actantiaI position. In this sense, the subject, principal example of incomplete lekton, is an incorporeal. The Stoics, therefore, had already de-psychologized semantics, so that we can translate semainomenon as «content» in Hjelmslev’s sense, that is, as a position within a system, the result of an abstract segmentation of the noetic field, a cultural unit (rather than a mental image, a thought, or an engram).
When the Stoics speak of the signs (semeia), they seem to refer to something immediately evident which leads to some conclusions about the existence of something not immediately evident. The sign can be commemorative: in this case it derives from an association, confirmed by preceding experience, between two events. On the basis of past experi-ence I know that, if there is smoke, then there must be fire. But the sign can also be indicative. In this case it points to something which has never been evident and probably will never be, such as the motions of the body which signify the motions of the soul, or the bodily humors which by passing through the skin indicate that there must be perceptible (but unperceived) pores.
In all these cases, the signs seem to be physical events: the smoke, the presence of milk revealing birth, the light revealing the day, and so on. Yet, the fact that the events, the transitory state of the bodies, are called incorporeals should give
