Ŏn-to-lŏg'ic or Ŏn-to-lŏg'ic-al, a.

a. [Fr. ontologique, Sp. ontologico.] Pertaining to the science of being in general, and its essential attributes and relations, and also to the argument for the being of God from the necessities of thought or of being.

Ontological proof, the a priori argument for being in general, and for the being of God, and its essential attributes and relations, derived from the necessary elements involved in the very idea of God. According to others, it is the argument derived from the necessary existence of time and space, and hence the necessary existence of some being to fill and occupy them.