5. When society and its various classes and interests are the subject-matter of the ideas which are in operation, the development may be called _political_; as we see it in the growth of States or the changes of a Constitution. Barbarians descend into southern regions from cupidity, and their warrant is the sword: this is no intellectual process, nor is it the mode of development exhibited in civilized communities. Where civilization exists, reason, in some shape or other, is the incentive or the pretence of development. When an empire enlarges, it is on the call of its allies, or for the balance of power, or from the necessity of a demonstration of strength, or from a fear for its frontiers. It lies uneasily in its territory, it is ill-shaped, it has unreal boundary-lines, deficient communication between its principal points, or defenceless or turbulent neighbours. Thus, of old time, Eubœa was necessary for Athens, and Cythera for Sparta; and Augustus left his advice, as a legacy, to confine the Empire between the Atlantic, the Rhine and Danube, the Euphrates, and the Arabian and African deserts. In this day, we hear of the Rhine being the natural boundary of France, and the Indus of our Eastern empire; and we predict that, in the event of a war, Prussia will change her outlines in the map of Europe. The development is material; but an idea gives unity and force to its movement. And so to take a case of national politics, a late writer remarks of the Parliament of 1628-29, in its contest with Charles, that, so far from encroaching on the just powers of a limited monarch, it never hinted at the securities which were necessary for its measures. However, "twelve years more of repeated aggressions," he adds, "taught the Long Parliament what a few sagacious men might perhaps have already suspected; that they must recover more of their ancient constitution, from oblivion; that they must sustain its partial weakness by new securities; that, in order to render the existence of monarchy compatible with that of freedom, they must not only strip it of all it had usurped, but of something that was its own."[43:1] Whatever be the worth of this author's theory, his facts or representations are an illustration of a political development. Again, at the present day, that Ireland should have a population of one creed, and a Church of another, is felt to be a political arrangement so unsatisfactory, that all parties seem to agree that either the population will develope in power or the Establishment in influence.