But except for such seasons of temporary exaltation, and except for those individuals who are endowed with an archaic temperament of the predatory type, together with the similarly endowed body of individuals among the higher and the lowest classes, the inertness of the mass of any modern civilized community in this respect is probably so great as would make war impracticable, except against actual invasion.

The habits and aptitudes of the common run of men make for an unfolding of activity in other, less picturesque directions than that of war.
This class difference in temperament may be due in part to a difference in the inheritance of acquired traits in the several classes, but it seems also, in some measure, to correspond with a difference in ethnic derivation.

The class difference is in this respect visibly less in those countries whose population is relatively homogeneous, ethnically, than in the countries where there is a broader divergence between the ethnic elements that make up the several classes of the community.

In the same connection it may be noted that the later accessions to the leisure class in the latter countries, in a general way, show less of the martial spirit than contemporary representatives of the aristocracy of the ancient line.

These nouveaux arrives have recently emerged from the commonplace body of the population and owe their emergence into the leisure class to the exercise of traits and propensities which are not to be classed as prowess in the ancient sense.
Apart from warlike activity proper, the institution of the duel is also an expression of the same superior readiness for combat; and the duel is a leisure-class institution.