John Buridan (c. 1292-1362)

Important though he is as a logician, Ockham was not very influential on the continent. It could be said that in the fourteenth century John Buridan dominated semantics on the continent, especially in Paris. His tract on suppositions, part of his Summulae, was very influential in Europe (John Buridan 1998).

Like Ockham, Buridan is a nominalist. He acknowledges only individual substances and individual accidents, both existing on themselves. How these two kinds form a unity does not seem to be his main concern. His interest is in semantics, and traditional metaphysical questions are solved semantically.

A human being possesses the power to express a word (spoken or written) according to the institution given in order to make his thoughts clear. Buridan is especially interested in the conventional level, and takes that more seriously than any of his predecessors. For instance, to the single word ‘‘chimera’’ correspond three different concepts, viz., those of goat, stag, and lion.

Signification is primarily a property of conventional signs. These are labels of concepts and can be replaced at will. Concepts determine the truth of a proposition, so they have objective value, but Buridan interprets them as the way in which man approaches reality. Man is not an objective, calculating being who automatically reproduces truth, but one who speaks or writes true, or false, propositions depending on the way under which he understands reality.

Buridan develops his theory on the properties of terms in the framework of his commentary on Peter of Spain. It should be noted that this text of Peter’s is not the original one, and Buridan does not follow it slavishly. Every now and then he seems to be annoyed with it.

Supposition can be divided into personal and material, thus into two kinds, not three, as is traditionally the case. Personal supposition is when a subject or predicate has supposition in a proposition for its ultimate significate(s), for instance, the term ‘‘man’’ - not the term ‘‘chimera,’’ because this does not possess a single ultimate significate in reality.

Material supposition is when a term has supposition for itself, or for a like term, or for a concept (which is called its immediate significate), according to which it is imposed to signify. For instance, the term ‘‘man’’ in ‘‘man is monosyllabic,’’ and ‘‘man’’ in ‘‘man is a species.’’

In Buridan’s material supposition, simple supposition is included. He is well aware that some adopt the property of simple supposition, for instance of ‘‘man’’ in ‘‘man is a species.’’ He rejects it, however, and adds that Aristotle had already done so. Buridan calls both cases ‘‘material supposition,’’ in line with his ontology. Simple supposition suggests the existence of universals outside the mind, and this kind does not exist, other than the ‘‘ancients’’ say. Universals are just concepts, by which the mind conceives more than one thing in an indifferent way.

Buridan defines the notion of natural supposition in another way than Peter of Spain does. Natural supposition is, for instance, of ‘‘thunder’’ in ‘‘thunder is a sound in the cloud.’’ The term stands for all occurrences of thunder in the past, present, future, and possible tense. Taken this way, it is a scientific proposition.

Other properties of terms Buridan acknowledges are appellation, ampliation, and restriction, not copulation, a property that does not play a part any more. Appellation is the property of a term according to which a term put in a proposition appellates its form, i. e., those things which the term connotes, and it appellates them as adjacent, either in the present, or in the past, or in the future, or in possibility. Buridan gives an example: ‘‘The just devil runs.’’ He analyses it as follows: the subject of this proposition (‘‘just devil,’’ i. e., this complex term) does not supposit for anything. Still, ‘‘just’’ appellates justice, as adjacent to the devil for which the term ‘‘devil’’ would have supposition if it would be the subject or the predicate of the proposition.

There is an interesting case of appellation in propositions with a verb denoting an inner act of the mind, such as ‘‘to know,’’ ‘‘to promise.’’ The famous example is ‘‘I know the one coming’’ (cognosco venientem). The term ‘‘coming’’ appellates ‘‘to come.’’ The proposition expresses that I know the one only as far as he is coming. Still, he may be my father, whom I know very well, but at that moment I do not know that he is the one coming. In this case, ‘‘you know the one coming’’ is false, though in fact it is your father. If one says, ‘‘the coming one, you know,’’ in which the substantival adjective is put before the verb, the proposition is true. According to that word order, the aspect of coming does not fall under the scope of the verb ‘‘to know,’’ and is not necessary for the truth of the proposition.

Ampliation is the widening of the supposition of a term, e. g., ‘‘A’’ in ‘‘A will run’’ which means, Buridan says that ‘‘what is or will be A, will run.’’ It is ampliated beyond its ‘‘status,’’ Buridan says. By ‘‘status’’ he means the condition by which a term signifies all its significates in the present.

Restriction is also a property of a term, e. g., of ‘‘man’’ in ‘‘every white man will run.’’ Here ‘‘man’’ is restricted within its status, and stands for all men in the present and future, due to the verb in the future, but is restricted to white men.

See also:  > Anselm of Canterbury > John Buridan