Between the lowest and the highest degree of spiritual and corporal perfection, there is an almost infinite number of intermediate degrees. The succession of degrees comprises the Universal Chain. It unites all beings, ties together all worlds, embraces all the spheres. One SINGLE BEING is outside this chain, and this is HE who made it.

Contemplation de la nature (1764), Vol. 1, 27. Trans. Stephen Jay Gould, Ontogeny and Phylogeny (1977)