This chapter examines some special theses of the analytic movement. The business of philosophy is to understand; to understand is to explain; and to explain is to place things in a context that reveals them as necessary. Such explanation is genuine discovery; the necessities thought discerns in things are not made by us, and neither are such values as beauty, or the goodness of justice or happiness. It is the philosophy of analysis, an elusive and protean philosophy that is in course of such rapid development that what one says about it may be out of date in a month. The weapon with which they sought to dispatch the philosophers was the principle of verification. The first was the 'methodological solipsism' accepted in the early days by Wittgenstein and Carnap. Most positivists inclined to a second and more liberal interpretation of their criterion. Professor Schlick adopted a third and greatly liberalized version of the principle.