Species are real, independent of the mind, and living species are caused by their common specific nature. Nicholas of Cusa thus answers Porphyry's question the understanding gathers species and genera together through comparison, so that the universals are likenesses of nature. Genera and species exist both in the mind and in nature. Likewise the biformed births of animals, mixed of different species. That God created one species for each natural order of plants differing in habit and fructification from all others. These species, mutually fertile, gave birth to as many genera as there were different parents, their fructification somewhat changed. It was, on the whole, the former tendency that prevailed in early modern biology. When it existed, before or after, it was motivated by piety rather than science. The transcendentalists however appear to be motivated also by a neo-Platonic philosophy.