[9] Like many other evolutionists of the time, Shaler incorporated basic tenets of natural selection—chance, contingency, opportunism—into a picture of order, purpose and progress in which characteristics were inherited through the efforts of individual organisms.

In Nature and Man in America, Shaler justifies the superiority of the Aryan race based on their development within European topography, "marvelously suited to be the cradles of people", erroneously attributing their origin to the Scandinavian provinces, "a field which seems to have been the seat of the strongest men in the world for thousands of years."

Expanding upon this logic, Shaler explains that a Scandinavian origin is most fitting because it would seem strange that the "most vigorous and at the same time the most plastic of the world-peoples should have developed among the limited opportunities afforded by high Asia."

Similarly, Shaler disparages the topography of the Americas, Africa, and Australia, claiming that these continents "have shown by their human products that they are unfitted to be the cradle places of great peoples."

Although he explains that its "large, simple, and easily comprehensible geographic features" as well as unfavorable climate for agriculture render the continent "unfit to cradle great peoples", he argues that the topography is perfectly suited for a race with better characteristics.

Expressing concern that the South will "release into barbarism", Shaler proposes that "the advance of the negro to a satisfactory grade of development still depends upon his remaining in close contact with the superior race.