OPPOSITION

The formal relations between pairs of propositions having the same subjects and predicates, but varying in quality or quantity are called species of opposition. The four propositions so constituted are: the universal affirmative, called A ; the particular affirmative, called I ; the universal negative, called E ; and the particular negative, called O. Of these, A and O are evidently contradictories, for A, affirming a predicate of everything subsumed under a subject, and O, denying the predicate of at least one instance of that subject, cannot both be true and cannot both be false. So also I, affirming the predicate of some instance of the subject, and E, denying it of everything the subject denotes, are contradictories. These relations hold, regardless of the existential import ascribed to categorical propositions.

Subalternation and Superalternation. Respecting existential import, one school understands particular propositions as asserting the existence of what their subjects signify, and understands universals as leaving the question of existence open. On this interpretation, there are no other relations between these propositions: A and E, A and I, E and O, are independent of each other. Another school, however, interprets the affirmatives as existential, so that they are false whenever nothing corresponding to their subjects exists, their contradictories being therefore true. With this interpretation, another relation between these propositions comes to light: universals imply particulars of like quality. This relation, commonly called subalternation, is really twofold; unlike contradiction, it is not symmetrical. The truth of either contradictory implies the falsity of the other. By contrast, the truth of the universal implies the truth of the particular, but not vice versa. For precision's sake, therefore, it is well to call the relation of the universal to the particular, superalternation; that of the particular to the universal, subalternation. The universal is the superaltern; the particular, the subaltern.

Contrariety and Subcontrariety. Logicians have long employed the so-called "square of opposition" to illustrate these relations and others derived from them. At the upper corners of this square are the symbols for the universals, at the lower corners, those for the particulars. Each is connected by a diagonal with its contradictory. From the relations described, two others are deduced. Since A implies the falsity of O, and the falsity of O implies that of E, by the principle that implication is transitive, one infers that A implies that E is false, that is, that either A or E is false. The falsity of A, however, implies nothing about E, nor does the falsity of E imply anything about A. For from the falsity of A nothing follows but the truth of O, which implies nothing with regard to E ; and the falsity of E implies only the truth of I, which implies nothing about A. This relation, represented by the upper horizontal line, according to which either A or E or both are false, is called contrariety.

The relation between particulars is shown in a similar manner. The falsity of I implies the truth of E, which implies that of O. Again, since implication is transitive, one concludes that either I or O is true. But the truth of I implies only that E is false, from which fact nothing follows as regards O ; and O implies nothing but the falsity of A, which determines nothing about I. Thus particulars may be both true, or one may be true while the other is false, but they cannot both be false. This relation, represented by the lower horizontal line, is called subcontrariety.

Implied Relationships. On the interpretation of categorical propositions first mentioned, there is no square of opposition for propositions of this kind, but only a "cross of contradiction," representing the relations of A and O, and of I and E. Nevertheless, the square is not without significance in illustrating the relationships between propositions of any kind; the principles of contradiction and of implication, which are its basis, are of universal validity. For example, if a proposition, p, implying another, q, replaces A, while q, not-p, and not-q, replace I, O, and E, respectively, the following conclusions result: not-q implies not-p ; p and not-q are contraries; and q and not-p are subcontraries. Similar relations could be deduced on the supposition that p and q were contraries, or that they were subcontraries. Aristotle's discussion of the contraries, "Socrates is well" and "Socrates is ill," may be illustrated by this device (Cat. 13b 26–35). The square shows that "Socrates is well" implies its obverse, as does "Socrates is ill," but that neither is implied by its obverse; and that either "Socrates is not well" or "Socrates is not ill" must be true.

See Also: proposition; logic.

Bibliography: m. ghio, Enciclopedia filosofica (Venice-Rome 1957) 3:1055–56. j. a. oesterle, Logic: The Art of Defining and Reasoning (2d ed. Englewood Cliffs, N.J, 1963). e. d. simmons, The Scientific Art of Logic (Milwaukee 1961). v. e. smith, The Elements of Logic (Milwaukee 1957). j. j. doyle, "The Square of Opposition in Action," The New Scholasticism 35 (1961) 41–75.

[j. j. doyle]

op·po·si·tion / ˌäpəˈzishən/ • n. resistance or dissent, expressed in action or argument: there was considerable opposition to the proposal the regime cracked down against the threat of opposition. ∎  (often the opposition) a group of adversaries or competitors, esp. a rival political party or athletic team. ∎  (the opposition) the principal political party opposed to the one in office. ∎  a contrast or antithesis: a nature-culture opposition. ∎ Logic (of two propositions) the relation of having the same subject and predicate, but differing in quantity, quality, or both. ∎  Astron. & Astrol. the apparent position of two celestial objects that are directly opposite each other in the sky, esp. when a superior planet is opposite the sun.PHRASES: in opposition in contrast or conflict: they found themselves in opposition to federal policy.DERIVATIVES: op·po·si·tion·al / -shənl/ adj.

opposition. The concept of a loyal parliamentary opposition grew slowly for two reasons. As long as the monarch played an active part in government, opposition was bound to be tainted with disloyalty: though the opposition to Charles I in the 1640s claimed to be loyal and conservative, it ended by cutting his head off and abolishing the monarchy. Secondly, the existence from 1688 until 1760 of an active Jacobite cause retarded the concept since some of the Tories in opposition undoubtedly wished to overthrow the regime itself. Nevertheless, the concept made progress in the 18th cent. and was helped by the fact that successive princes of Wales, who could scarcely be accused of treason, went into opposition to their father's government. Monarchs continued to find the concept suspect and the protestations of loyalty insincere: George III observed in 1778 that ‘men who have been active in opposition rarely make useful servants to the crown’—a phrase which reveals a slightly old-fashioned attitude. Charles Fox, on the other hand, declared in 1783 that a ‘systematic opposition to a dangerous government is, in my opinion, a noble employment for the brightest faculties’. The phrase ‘His Majesty's Opposition’ was first used jocularly by Hobhouse in 1826 and was so useful that it took root. The validity of the concept was subsequently recognized in a variety of ways. From 1937 the leader of the opposition received an official salary and is now provided with an official car and chauffeur: the chief opposition whip and two assistant whips also receive salaries. He is accorded prominence in public ceremonies, such as the Armistice Day commemoration. All parliamentary parties have since 1975 received some public funding. Governments sometimes offer confidential information to opposition spokesmen, who are frequently wary lest it blunt their attacks. The concept of opposition is close to the heart of parliamentary democracy, not merely in curbing government, resisting encroachments upon liberty, and keeping ministers on their toes, but as a stabilizing factor by offering to the most embittered of citizens hope that governments do not last forever.

J. A. Cannon

OPPOSITION.
1. In LINGUISTICS, a functional contrast between partially similar elements in a language system: for example, between the meanings and uses of the negative prefixes un- and non- in unprofessional and nonprofessional, where un- is judgemental and non- is neutral.

2. In PHONETICS, the nature of the contrast between a pair of PHONEMES: for example, /t/ is a voiceless alveolar stop and /d/ is a voiced alveolar stop. The two consonants agree in place and manner of articulation, but fall into the opposition of voicing. See MINIMAL PAIR.