  Human nature includes all the forms of nonhuman nature, but they lie dormant, as it were, in a state of virtual energy. Cardano always pays special attention to those aspects of human nature that seem to indicate a close link with animals and lower forms of life. Unsurprisingly, comparative analyses between humans and animals abound in his works. Among the questions dealing with the relationships between human and nonhuman animals, Cardano is particularly interested in exploring whether reason is an exclusive prerogative of human beings or it should rather be seen as the result of biological development (De natura, OO, II, 283b–284a).