ular propositions are established, one is never entitled to regard the universal proposition as conclusively verified. Nor does the falsity of one statement negate the universal proposition. The logical asymmetry in the relationship of universal and singular propositions that has led some philosophers to adopt the possibility of falsification rather than that of verification as their criterion of empirical significance. Ayer claims philosophers have reached propositions which need not wait upon other propositions for the determination of their truth or falsehood, but are such that they can be directly confronted with the given facts. These are called basic propositions. The distinction between them and other propositions is fairly legitimate, "...then we may confine ourselves to questions concerning the nature of basic propositions and the manner in which our determination of their validity depends upon our experience." (4) The legitimacy of the distinction between basic and other propositions is implicitly acknowledged by philosophers who reject the notion of agreement with reality as a criterion of truth. Propositions can only be compared to each other, and cannot be compared with reality or experience. There is another status of basic propositions, a class of "protocol propositions." For a sentence to express a protocol propositions it is necessary that it should contain the name or description of an observer and some words referring to an act of observation. The claims for this form have the advantage of giving protocol propositions greater stability. One can make the truth and falsehood of any proposition whatsoever depend upon its compatibility or incompatibility with other propositions. One often does not recognize other criterion. In this respect, protocol propositions are not allowed any advantage. A protocol proposition is not one which can be directly verified by observation, for one can deny that this is possib...
