Being

Being is the fact or act of existing: that something is, rather than nothing. Its study, ontology, is the core of metaphysics. Parmenides first made it a philosophical theme, arguing that being is one and unchanging and that non-being cannot be thought; Plato and Aristotle asked what it is to be, and Aristotle described first philosophy as the study of being as being.

The traditions differ on how the ultimate relates to being. For Thomas Aquinas, God is being itself, whose essence is to exist; Ibn Sīnā had earlier described God as the Necessary Existent, and Mullā Ṣadrā made existence the one reality in many degrees. For Advaita, Brahman is pure being (sat), consciousness and bliss. For Plotinus and Pseudo-Dionysius, on the other hand, the ultimate is beyond being, and being is its first product.

Buddhist philosophy is wary of the language of being: Madhyamaka denies that anything has being in itself, though it equally denies that things simply do not exist. In the twentieth century Heidegger argued that Western philosophy had forgotten the question of being.