And this deeper and more general cause, when we look for it, is sufficiently obvious.

It consists of the fact that, owing to the millions of years of struggle to which was due, in the first place, the evolution of man as a species, and, in the second place, the races of men in their existing stages of civilisation, the fighting instinct is, in the strongest of these races, inherent after a fashion in which the industrial instincts are not; and will always prompt numbers to do, for the smallest wage or none, what they could hardly, in its absence, be induced to do for the highest.

This instinct, no doubt, is more controlled than formerly, and is not so often roused; but it is still there.

It is ready to quicken at the mere sound of military music; and the sight of regiments marching stirs the most apathetic crowd.
High-spirited boys will, for the mere pleasure of fighting, run the risk of having their noses broken, while they will wince at getting up in the cold for the sake of learning their lessons, and would certainly rebel against being set to work as wage-earners at a task which involved so much as a daily pricking of their fingers.
Here we have the reason, embodied in the very organism of the human being, why military activity is something essentially distinct from industrial, and why any inference drawn from the one to the other is valueless.

And to this primary fact it is necessary to add another.