What influence will the new tendencies in political thought have on the emotional and intellectual conditions of political solidarity? In the old city-states, where the area of government corresponded to the actual range of human vision and memory, a kind of local emotion could be developed which is now impossible in a 'delocalised' population. The solidarity of a modern state must therefore depend on facts not of observation but of imagination. The makers of the existing European national states, Mazzini and Bismarck, held that the possible extent of a state depended on national homogeneity, _i.e._ on the possibility that every individual member of a state should believe that all the others were like himself. Bismarck thought that the degree of actual homogeneity which was a necessary basis for this belief could be made by 'blood and iron'; Mazzini thought that mankind was already divided into homogeneous groups whose limits should be followed in the reconstruction of Europe. Both were convinced that the emotion of political solidarity was impossible between individuals of consciously different national types. During the last quarter of a century this conception of the world as composed of a mosaic of homogeneous nations has been made more difficult (a) by the continued existence and even growth of separate national feelings within modern states, and (b) by the fact that the European and non-European races have entered into closer political relationships. The attempt, therefore, to transfer the traditions of national homogeneity and solidarity either to the inhabitants of a modern world-empire as a whole, or to the members of the dominant race in it, disguises the real facts and adds to the danger of war. Can we, however, acquire a political emotion based, not upon a belief in the likeness of individual human beings, but upon the recognition of their unlikeness? Darwin's proof of the relation between individual and racial variation might have produced such an emotion if it had not been accompanied by the conception of the 'struggle for life' as a moral duty. As it is, inter-racial and even inter-imperial wars can be represented as necessary stages in the progress of the species. But present-day biologists tell us that the improvement of any one race will come most effectively from the conscious co-operation, and not from the blind conflict of individuals; and it may be found that the improvement of the whole species will also come rather from a conscious world-purpose based upon a recognition of the value of racial as well as individual variety, than from mere fighting. HUMAN NATURE IN POLITICS INTRODUCTION The study of politics is just now (1908) in a curiously unsatisfactory position.