Philosophy— the avowed body of theoretical science in the late medieval time— had grown out of the schoolmen's speculations in theology, being in point of derivation a body of refinements on the divine scheme of salvation; and with a view to quiet title, and to make manifest their devotion to the greater good of eschatological expediency, those ingenious speculators were content to proclaim that their philosophy is the handmaid of theology— Philosophia theologia ancillans. But their philosophy has fallen in to the alembic of idle curiosity and has given rise to a body of modern science, godless and unpractical, that has no intended or even ostensible bearing on the religious fortunes of mankind; and their sanctimonious maxim would today be better accepted as the subject of a limerick than of a homily.

For American naturalists, nature consists of everything there is. Nothing is “outside” nature. Whatever exists is no more or less an aspect of nature than anything else. Furthermore, nature is, to one degree or another, objective, which means that it has characteristics the content of which is not determined by our opinions of them— nature may be studied and known. Crucially, human beings are part of that knowable nature. American naturalists reject any dichotomy between nature and human being. Human life, including its purposes, goals, meanings, values, and ideals, is wholly natural.