In trying to indicate the importance, I have had to dwell upon the difficulty, of applying anything like scientific methods to political problems. I shall conclude by trying once more to indicate why, in spite of this, I hold that the attempt is desirable, and may be fruitful. People sometimes say that scientific methods are inapplicable because we cannot try experiments in social matters. I remember being long ago struck by a remark of Dr. Arnold, which has some bearing upon this assertion. He observed upon the great advantage possessed by Aristotle in the vast number of little republics in his time, each of which was virtually an experiment in politics. I always thought that this was fallacious somehow, and I fancy that it is not hard to indicate the general nature of the fallacy. Freeman, upon whose services to thorough and accurate study of history I am unworthy to pronounce an eulogy, fell into the same fallacy, I fancy, when he undertook to write a history of Federal Governments. He fancied that because the Achæan League and the Swiss Cantons and the United States of America all had this point in common, and that they represented the combinations of partially independent States, their history would be in a sense continuous. The obvious consideration that the federations differed in every possible way, in their religions and state of civilisation and whole social structure, might be neglected. Freeman's tendency to be indifferent to everything which was not in the narrowest sense political led him to this--as it seems to me--pedantic conception. If the prosperity of a nation depended exclusively upon the form of its government, Aristotle, as Arnold remarks, would have had before him a greater number of experiments than the modern observer. But the assumption is obviously wrong. Every one of these ancient States depended for its prosperity upon a vast number of conditions--its race, its geographical position, its stage of development, and so forth, quite impossible to tabulate or analyse; and the form of government which suited one would be entirely inapplicable to another. To extricate from all these conflicting elements the precise influence due to any institutions would be a task beyond the powers of any number of philosophers; and indeed the perplexity would probably be increased by the very number of experiments. To make an experiment fruitful, it is necessary to eliminate all the irrelevant elements which intrude into the concrete cases spontaneously offered by nature, and, for example, to obtain two cases differing only in one element, to which we may therefore plausibly attribute other contrasts. Now, the history of a hundred or a thousand small States would probably only present the introduction of new and perplexing elements for every new case. The influence, again, of individuals, or accident of war, or natural catastrophes, is greater in proportion as the State is smaller, and