Thirdly we have the limiting cases of this in the inductive syllogism 5ui 7riu'mw, 7 a syllogism in the third figure concluding universally, and yet valid because the copula expresses equivalence, and in analogy 8 in which, it has been well said, instances are weighed and not counted.
One of these, Summa de assumpto homine, is of a theological character, dealing with the humanity of Christ; the other, Summa de matrimonio, is a legal argument, to the effect that the essential fact in marriage is neither, as Gratian maintains, the copula, nor, as Peter Lombard, consent by verba de praesenti, but mutual traditio.
Moreover, it is very probable that conjugation occurs soon after the arrival of the parasites in their specific invertebrate host; and this act may perhaps give rise to an aflagellar copula, which is gregariniform and comparable to an ookinete.
- Another example of Aristotle's gradual desertion of Plato is exhibited by the De Interpretatione as compared with the Prior Analytics, and it shows another gradual history in Aristotle's philosophy, namely, the development of subject, predicate and copula, in his logic.
In the syllogism " Every man is mortal and Socrates is a man," if in the minor premiss the copula " is " were not disengaged from the predicate " man," there would not be one middle term " man " in the two premisses.
It is not necessary in every proposition, but it is necessary in the arrangement of a syllogism, to extricate the terms of its propositions from the copula; e.g.
Secondly, he made no division of logic. In the Categories he distinguished names and propositions for the sake of the classification of names; in the De Interpretatione he distinguished nouns and verbs from sentences with a view to the enunciative sentence: in the Analytics he analysed the syllogism into premisses and premisses into terms and copula, for the purpose of syllogism.
In point of fact, he analysed it into premises, but then analysed a premise into terms, which he divided into subject and predicate, with the addition of the copula " is " or " is not."
In the Analytics he took the final step of originating the logical analysis of the proposition as premise into subject and predicate as terms mediated by the copula, and analysed the syllogism into these elements.
(5) When a judgment is expressed by a proposition, the proposition expresses the results of the division by two terms, subject and predicate, and by the copula that what is signified by the subject is what is signified by the predicate; and the proposition is a combination of the two terms; e.g.
Without realizing their debt to tradition, Herbart, Mill and recently Sigwart, have repeated Aristotle's separation of the copula from the verb of existence, as if it were a modern discovery that " is " is not the same as " exists."
It may be added that they do not quite realize what the copula exactly signifies: it does not signify existence, but it does signify a fact, namely, that something is (or is not) determined, either absolutely in a categorical judgment, or conditionally in a conditional judgment.
But, in the first place, primary judgments signify this existence never by the copula, but sometimes by the predicate, and sometimes by the subject; and, secondly, it does not follow that all judgments whatever signify existence.
All categorical judgment is an unconditional belief in the fact, signified by the copula, that a thing of some sort is (or is not) determined; but some categorical judgments are also beliefs that the thing is an existing thing, signified either by the subject or by the predicate, while others are not beliefs that the thing exists at all, but are only beliefs in something conceivable, or nameable, or in something or other, without particularizing what.
But even the normal proposition in the syllogistic form tertii adjacentis, with subject, predicate and copula, is seldom a complete expression of the judgment.
The symbol of equality (=) is not the same as the copula (is); it means " is equal to," where " equal to " is part of the predicate, leaving " is " as the copula.
The symbolic logic, which confuses " is " with " is equal to," having introduced a particular kind of predicate into the copula, falls into the mistake of reducing all predication to the one category of the quantitative; whereas it is more often in the substantial, e.g.
Such speculative views are associated with the revival of another traditional piece of mysticism - the Holy Spirit the Copula or bond of union in the Godhead.
Thus, the courts recognize marriages by verba de praesenti or by verba de futuro cum copula - in this last matter following a decree of Gregory IX.
The meaning of the copula and the relation of thoughts to the objects of which they are the thoughts are as much involved as the nature of being.
Subject, predicate and copula.'
An old error that we may have a valid syllogism from merely negative premises (ex omnibus negativis), long ago answered by Alexander and Boethius, is now revived by Lotze, Jevons and Bradley, who do not perceive that the supposed second negative is really an affirmative containing a " not " which can only be carried through the syllogism by separating it from the copula and attaching it to one of the extremes, thus: The just are not unhappy (negative).