Disjunction - Definition and Examples

The dictionary definition of disjunction is the act of disjoining or the state of being disjoined. In grammar and semantics, a coordinate construction uses  disjunctive conjunction (usually or  or either/or) to indicate a contrast. The items on either side of the disjunctive conjunction are called disjuncts. Disjunctions are  compound propositions that are only true if at least one of several alternatives is also true  and are commonly used in rhetorical arguments, although they also have applications in the fields of science and mathematics.   Basic Example of Disjunction   The statement p or q is a disjunction. It is true when p is true, or when q is true, or when p and q are both true; it is false when both p and q are false. For example, Either Mac Did it or Bud did.  This statement is true if either or both of its component statements, or disjuncts, is true.—From Critical Thinking by  W. Hughes and J. Lavery Exclusive vs. Inclusive,  Example I In everyday language, disjunction is normally expressed using the word or...Indeed, perhaps the hottest issue in linguistics studies of disjunction is that of whether the basic meaning of or is inclusive, exclusive, or whether there are in fact two quite distinct meanings. Intuitively, there do seem to be some contexts in which or is inclusive, and others in which it is exclusive. If an advertisement for a lecturing position was phrased, Applicants must have either a Ph.D. or teaching experience, this would surely not be taken to exclude someone who had both a Ph.D. and teaching experience; hence this would be an inclusive disjunction. On the other hand, if a mother said to her son, You can either have some candy or some cake, her instruction surely would have been disobeyed if her son had both candy and cake; hence this is an exclusive disjunction. . .  While the extreme claim that or is always inclusive can be rejected, it is still possible that the inclusive interpretation is th e basic one.—From The Language and Thought of Disjunction by  S. E. Newstead and R. A. Griggs Exclusive vs. Inclusive,  Example II The choice between exclusive and inclusive interpretations depends on the semantic content of the disjuncts  together with background knowledge and  context.  The letter was posted on Tuesday or Wednesday  will normally be interpreted  exclusively  because letters are normally posted only once, whereas,  Tom has missed the train or the train is late,  will normally have an inclusive interpretation because the likely context is one where Im advancing reasons for Toms absence, and if he missed the train I have no evidence as to whether it is late or not.—From  English Grammar: An Outline by  Rodney Huddleston Sources Hughes, W;  Lavery, J.Critical Thinking. Broadview. 2004Newstead, S.E.;   Griggs,  R. A. The Language and Thought of Disjunction in Thinking and Reasoning: Psychological Approaches. Routledge. 1983Huddleston, Rodney. English Grammar: An Outline. Cambridge University Press. 1988