From the plexus of conscience and reality as explained by Millán-Puelles, we
understand the thesis -pace Descartes and Husserl- that ontology is possible
only when it is understood as a description of the conditions of the natural
being. To be by nature a rational being is to be by nature an existent thought.
If thought is what results from the activity proper to reason due to its
belonging to the world, then reason that thinks has no need of any certainty
by way of reflection that it thinks.