Occasionally there has appeared in the history of philosophy a thinker who has become aware of the chaotic condition of philosophy and of the intellectual anarchy that exists in all of its branches, and has attempted to remedy the situation. Descartes cast about for a guiding principle, a compass which would show him the way through the treacherous terrain of philosophy. As is well known he devised the method of systematic doubt, by means of which he hoped to discover an axiom on which he could securely erect a system of basic and reassuring beliefs. Leibniz had before his mind the notion of an ideal language which would by calculation solve problems with certainty. With this he thought we “should be able to reason in metaphysics and morals in much the same way as in geometry and analysis.” Descartes' attempt was a failure; and nothing came of Leibniz's ideal, even with the development of modern symbolic logic. Russell's claim that “logic is the essence of philosophy” frightened many philosophers and gave new hope to others; but his claim was as empty as the proverbial political promise. With G. E. Moore we have a further attempt to introduce sobriety and certainty into philosophy and to make fruitful research possible in it. He has made prominent a method for obtaining results in philosophy; and he has also formulated a philosophical platform, i.e., set out a list of Common-sense propositions which he says are known to be true by everyone, philosopher as well as non-philosopher, and are not, therefore, open to debate. The method, which he used extensively and with great skill, is the method of analysing concepts.