Augustine (354-430) in De doctrina christiana, John Buridan (1301-1358) in Sophismata, William Ockham (1285-1349) in Summa of Logic worked out the medieval theory of signification:

• According to Augustine, “a sign is what shows both itself to the sense and something else besides itself to the mind.” (see also [2.6.2]). A more restrictive type of sign is the linguistic sign, defined by Ockham, as one which might well be a sign of itself.
• Meaningful utterances and inscriptions are both linguistic signs, their signification being defined by language-dependent conventions.
• Utterances immediately signify (R2) concepts, inscriptions immediately signify (R3) utterances, so utterances are prior to inscriptions.
• Inscriptions and utterances mediately signify concepts and objects (R4), (R5), (R6).
• Concepts are mental states of understanding of the objects immediately signified (R1). Due to their likness to the object, concepts do not vary from person to person or culture to culture. This is why (R1) is called natural signification.
• R1, R2, R3 are immediate significations, basic or primitive relations. R4, R5, R6 are mediate significations, derived relations.
• Inscriptions, utterances, and concepts are members of written, spoken, and respective mental languages. Since inscriptions and utterances are conventional, concepts are natural, the written and spoken languages are conventional, and the mental language is natural.

The following OntoUML diagram pictures the main classes of the medieval theory of signification:

Class	Description	Relations
Object	An object, a thing or state of affairs in the external world.
Concept	A concept [mental term] is an act of understanding of the Object signified: “There was a great disagreement in the Middle Ages about what it is that linguistic units signify, but there was universal agreement over the defining criterion, and that is what we are interested in now. Buridan mentions this criterion in discussing the fourth sophism of his: For ‘to signify’ is described as being ‘to establish the understanding’ of a thing. Hence a word is said to signify that the understanding of which it establishes in us. Thus: To signify x =df. to establish an understanding of x. The Latin here is ‘constituere intellectum’, construed with the genitive. ‘Understanding’ (= ‘intellectus’) in this context does not necessarily imply any kind of theoretical knowledge; to ‘understand’ x, in the sense relevant here, is simply to have a concept of x. In the end, therefore, the general idea is that a thing signifies what it makes us think of.”	signifies immediately (R1) Object; member of MentalLanguage
MenatalLanguage	“concepts play the role of terms, just like spoken and written terms, only instead of being terms in spoken or written language, concepts are terms in a kind of mental language. […] Buridan extends this notion to talk not just about mental terms but also about mental propositions: For every spoken [proposition] signifies a mental one similar to it or proportionally corresponding to it… Again, in the reply to his first sophism, he does the same thing. And I say that for the truth of a spoken proposition it does not suffice that it have a similar mental proposition corresponding to it in the mind, because that is common to every [spoken] proposition. So we can generalize: Spoken terms, spoken propositions, and perhaps units of spoken language generally, signify corresponding units of mental language. So too, one step further removed, do the units of written language. The point then is this: Mental language is to be viewed as a full-blown language in its own right.”	subkind of Language
Natural	“This means there is an important difference between [relations] R1 in our schema, on the one hand, and R2 and R3, on the other R1 is a relation of likeness or similarity, and so does not vary from person to person, or from culture to culture. It is an ontological relation, established by nature, not by chance or convention. Hence we will see our medieval authors saying that the kind of signification concepts have is natural signification, and that mental language is a natural language.”	characterizes MentalLanguage
LinguisticSign	“the same point is made in Augustine’s De dialectica, Ch. 5, although that work did not circulate widely in the Middle Ages: A sign is what shows both itself to the sense and something else besides itself to the mind. […] Ockham goes on immediately afterwards to define a more restrictive sense of ‘sign’. This more restrictive sense is the notion of a linguistic sign. […] in Ockham’s […] sense, a sign need not always signify something else, as Augustine and Ockham’s own first definition required. In other words, in the linguistic sense, a thing might very well be a sign of itself.“	signifies Concept or itself
Utterance	“utterances = voces. There is no uniformly good English translation for this word. Basically, a vox (plural voces) is a sound produced by the vocal apparatus of an animal. It may or may not mean anything. ‘Word’ is both too broad and too narrow a translation, too broad because we talk about written words as well as spoken ones, too narrow because it suggests meaningfulness. ‘Speech’ will work sometimes, but often suggests long-winded oratory, whereas a vox might be a single syllable. After long experience, I have adopted the policy of translating this word ‘utterance’” […]	subkind of LinguisticSign; signifies immediately (R2) Concept (relation R2 is also called a relation of correspondence.); signifies mediately Object (R5); member of SpokenLanguage
SpokenLanguage	“Spoken terms, spoken propositions, and perhaps units of spoken language generally, signify corresponding units of mental language.”	subkind of Language
Inscription	“‘written letters [inscriptions] signify utterances [that are] spoken or will be spoken. And they do not signify any things outside the soul, such as asses or rocks, except by means of the signification of utterances.’ For example, the written word dog, according to the claim in this first conclusion, signifies the spoken term ‘dog’. […] Buridan gives two illustrations, which he thinks support this first conclusion. Whether they really do support it or not doesn’t matter for the present. At any rate, they do illustrate his point, and that is enough for now. (1) First illustration: Teachers teach students to read and write by teaching them which letters go with which sounds. Thus, the written letter b goes with the spoken consonant ‘b’, the written letter a with the spoken vowel ‘a’, and so on. Under the name “phonics,” something like this method is often still used to teach children today. It makes even more sense in a language like Latin that is more phonetically spelled than English is. (2) Second illustration: Consider someone whose native tongue is Latin. (In fact, by the fourteenth century, there were effectively no native Latin speakers left. Latin was a second language, which one learned for certain specialized purposes: philosophical, theological, legal, medical, diplomatic, etc. But this does not affect Buridan’s point.) In order to get Buridan’s illustration to work, you have to suppose he is talking about an illiterate Latin speaker. Such a person, Buridan says, knows what the spoken sentence ‘A man is running’ (or rather its Latin equivalent ‘Homo est currens’) signifies, since he speaks Latin, after all. But he is left completely in the dark by the written sentence A man is running (or Homo est currens), because he is illiterate. On the basis of the illustration, Buridan seems to think the reason the man doesn’t know what the written sentence means is that he doesn’t know how to pronounce it. […] For the present, just note that Buridan here says that a written term [inscription] immediately signifies an utterance. The point is that Buridan is here talking about a written term — that is, a whole word, not just individual letters. […] And the first conclusion is that written letters signify utterances [that are] spoken or will be spoken. And they do not signify any things outside the soul, such as asses or rocks, except by means of the signification of utterances.”	subkind of LinguisticSign; signifies immediately (R3) Utterance; signifies mediately Concept and Object (R6) and (R4); member of WrittenLanguage
WrittenLanguage	“The actual statement of the first conclusion (with its reference to ‘written letters’), and the first illustration, suggest that Buridan is thinking that individual letters signify the correlated spoken phonemes. But in fact, Buridan wants to make a more general claim. It’s not just isolated letters that signify utterances, but rather written language as a whole that signifies spoken language. This is clearer in the second illustration, which operates on the level of whole words and sentences rather than of individual letters and phonemes. […] The general idea in all of this then is that written language is viewed as in some sense inferior to and dependent on spoken language. A written sentence, for example, signifies first of all the sounds you would utter if you read the sentence aloud. Of course, it also signifies whatever the spoken sentence signifies — but, as Buridan indicates at the end of his Conclusion 1, that is a secondary and derivative kind of signification”	subkind of Language
Convention	“relations R2 and R3 are not like this [R1]. They depend on the “nation,” on the linguistic community. Thus we will also see authors talking about the signification of words and inscriptions as conventional (= ad placitum, literally “at your pleasure”) signification. So too, we will see people refer to spoken and written language as a whole as artificial or conventional, in contrast to mental language, which is natural.”	relates Concept, Utterance and Inscription
Language	Language

Sources:

• All citations from: Spade, Vincent, “Thoughts, Words and Things: An Introduction to Late Mediaeval Logic and Semantic Theory”, Version 1.2: December 27, 2007
• Klima, Gyula, “John Buridan”, Oxford University Press, 2009
• Zupko, Jack, “John Buridan“, The Stanford Encyclopedia of Philosophy (Fall 2018 Edition), Edward N. Zalta (ed.)

First published: 19/8/2021