THE HUMAN NATURE AND MORALS OF THE CASE

which attempts to exact advantage for one party at the expense of the other. I am not arguing over again the thesis of the first part of this book; but, as we shall see presently, the general principle of the diminishing factor of physical force in the affairs of the world carries with it a psychological change in human nature which modifies radically our impulses to sheer physical conflict. What it is important just now to keep in mind, is the incalculable intensification of this diminution of physical force by our mechanical development. The principle was obviously less true for Rome than it is for Great Britain or America: Rome, however imperfectly, lived largely by tribute. The sheer mechanical development of the modern world has rendered tribute in the Roman sense impossible. Rome did not have to create markets and find a field for the employment of her capital. We do. What result does this carry? Rome could afford to be relatively indifferent to the prosperity of her subject territory. We cannot. If the territory is not prosperous we have no market, and we have no field for our investments, and that is why we are checked at every point from doing what Rome was able to do. You can to some extent exact tribute by force; you cannot compel a man to buy your goods by force if he does not want them, and has not got the money to pay for them. Now, the difference which we see here has been brought about by the interaction of a whole series of mechanical changes—printing, gunpowder, steam, electricity, improved means of communication. It is the last-named which has mainly created