Human beings, having, above all creatures, received the power of reason... need to be aware where nature is unaware. Nature reaches its culmination i… - Carl Linnaeus

No one has any right to be angry with me, if I think fit to enumerate man among the quadrapeds. Man is neither a stone nor a plant, but an animal, for such is his way of living and moving; nor is he a worm, for then he would have only one foot; nor an insect, for then he would have antennae; nor a fish, for he has no fins; nor a bird, for he has no wings. Therefore, he is a quadraped, had a mouth like that of other quadrapeds, and finally four feet, on two of which he goes, and uses the other two for prehensive purposes.

We imagine that the Creator at the actual time of creation made only one single species for each natural order of plants, this species being different in habit and fructification from all the rest. That he made these mutually fertile, whence out of their progeny, fructification having been somewhat changed, Genera of natural classes have arisen as many in number as the different parents, and since this is not carried further, we regard this also as having been done by His Omnipotent hand directly in the beginning; thus all Genera were primeval and constituted a single Species. That as many Genera having arisen as there were individuals in the beginning, these plants in course of time became fertilised by others of different sort and thus arose Species until so many were produced as now exist... these Species were sometimes fertilised out of congeners, that is other Species of the same Genus, whence have arisen Varieties.

Every genus is natural, created as such in the beginning, hence not to be rashly split up or stuck together by whim or according to anyone's theory.