 A standard (if not the standard) employment of “or” is in the specification of possibilities (one of which is supposed by the speaker to be realized, although he does not know which one), each of which is relevant in the same way to a given topic. |  Ramsey on conditionals:If two people are arguing “If p will q?” and are both in doubt as to p, they are adding p hypothetically to their stock of knowledge and arguing on that basis about q; so that in a sense “If p, q” and “If p, ¬q” are contradictories. |