War has been almost universal in human history over the last fifty thousand years. The constant feuding wars probably inhibited the growth of civilizations in various ways. Minor gains were destroyed, populations remained relatively sparse and spread out, the ecology was protected but few major innovations could occur. As soon as a group became prosperous and relaxed its war-like discipline it was destroyed by the warriors from poorer but more war-like neighbouring groups.
For many thousands of years the world saw the warlike, feuding, societies on the margins fight the settled, agrarian, civilizations at the centre. The greatest contest of all was between the pastoral nomads of central Asia, the Mongols, and the settled agrarian peoples whom they overran in China, India, Russia, Eastern Europe and the Middle East.
In this vast, thousand-year, clash of two forms of human organization, the Mongols destroyed vast civilizations and ruled three quarters of the Asian land mass up to the eighteenth century. Their technologies of destruction, principally the horse and Mongolian bow, were superior to the war technologies of settled States until about 1700. It was only the development of more sophisticated gunpowder weapons which gave the west the final advantage.
So, for a very long period, apart from honing male physique, encouraging heroic poetry, adding some footnotes to the art of war, improving horse breeding, and giving certain peoples a sense of purpose and heroic glory, war probably did little for human development. In the balance, the losses far outweighed the gains.
In one area of the world, however, war led to technical progress. The small kingdoms of western Europe were constantly at war from the middle ages on, and a rapid form of political ‘survival of the fittest’ developed. Very rapid developments in architecture, boat construction, navigation, metal working and some branches of physics and geometry emerged out of this desperate competition.
If Europe between about 1400 and 1800 had been as peaceful as China or Japan it is likely that much of the rapid increase in reliable knowledge and technical efficiency would not have occurred.
Without the advances in cannon boring made through these centuries, the steam engine cylinder could not have been made and no industrial revolution based on steam could have occurred. If we measure human progress by man’s capacity to control the physical world, then war of the west European kind did lead to a sort of progress. Yet this has to be placed against the horrors and miseries.