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. (shrink)