The ontological basis of modernity is an unresolved clash with the classical ontology of essence. This gives rise to a situation in which the true ontological foundation of everything man elaborates will consist in a continuous confrontation between the modern pretension with the classical ontological notions. For the praxis, such issue has as consequence the disappearance of the consideration of morality as practical knowledge. In such a situation bioethics is born as a result and reaction against it, and appears as a restoration of the notion of practical knowledge. Its development as a discipline will go through its split into various bioethical models, some of which will understand morality in its modern sense, while others will try to restore the consideration of morality as practical knowledge.