A man who knows, though he knows nothing more, that the moon is kept in its orbit by forces similar to or identical with those which cause the fall of an apple, knows something which only requires more definite treatment to be made into a genuine theory of gravitation. If, on the contrary, he merely pays himself with words, with vague guesses about occult properties, or a supposed angel who directs the moon's course, he is still in the unscientific stage. His theory is not science still in the vague, but something which stops the way to science. Now, if we can never hope to get further than the step which in the problem of gravitation represents the first step towards science, yet that step may be a highly important one. It represents a diversion of the current of thought from such channels as end in mere shifting sands of speculation, into the channel which leads towards some definite conclusion, verifiable by experience, and leading to conclusions, not very precise, but yet often pointing to important practical results. It may, perhaps, be said that, as the change which I am supposing represents only a change of method and spirit, it can achieve no great results in actual assignable truth. Well! a change of method and spirit is, in my opinion, of considerable importance, and very vague results would still imply an improvement in the chaos of what now passes for political philosophy. I will try to indicate very briefly the kind of improvement of which we need not despair. First of all, I conceive that, as I have indicated, a really scientific habit of thought would dispel many hopeless logomachies. When Burke, incomparably the greatest of our philosophical politicians, was arguing against the American policy of the Government, he expressed his hatred of metaphysics--the "Serbonian bog," as he called it, in which whole armies had been lost. The point at which he aimed was the fruitless discussion of abstract rights, which prevented people from applying their minds to the actual facts, and from seeing that metaphysical entities of that kind were utterly worthless when they ceased to correspond to the wants and aspirations of the peoples concerned. He could not, as he said, draw up an indictment against a nation, because he could not see how such troubles as had arisen between England and the Colonies were to be decided by technical distinctions such as passed current at _nisi prius_. I am afraid that the mode of reasoning condemned by Burke has not yet gone out of fashion. I do not wish to draw down upon myself the wrath of metaphysicians. I am perfectly willing that they should go on amusing themselves by attempting to deduce the first principles of morality from abstract considerations of logical affirmation and denial. But I will say this, that, in any case, and whatever the ultimate meaning of right and wrong, all political and social questions must be discussed with a continual reference to