They are rooted in ancient ontology itself, and it will not be possible to interpret that ontology adequately until the question of Being has been clarified and answered and taken as a clue—at least, if we are to have regard for the soil from which the basic ontological concepts developed, and if we are to see whether the categories have been demonstrated in a way that is appropriate and complete. We shall therefore carry the discussion of these presuppositions only to the point at which the necessity for restating the question about the meaning of Being become plain. There are three such presuppositions.
1. First, it has been maintained that 'Being' is the 'most universal' concept: τὸ ὄν ἐστι καθόλου μάλιστα πάντων.1 Illud quod primo cadit sub apprehensione est ens, cuius intellectus includitur in omnibus, quaecumque quis apprehendit. 'An understanding of Being is already included in conceiving anything which one apprehends as an entity.'1,ii But the 'universality' of 'Being' is not that of a class or genus. The term 'Being' does not define that realm of entities which is uppermost when these are Articulated conceptually according to genus and species: οὔτε τὸ ὄν γένος.iii The 'universality' of Being 'transcends' any universality of genus. In medieval ontology 'Being' is designated as a 'transcendens'. Aristotle himself knew the unity of this transcendental 'universal' as a unity of analogy in contrast to the multiplicity of the highest generic concepts applicable to things. With this discovery, in spite of his dependence on the way in which the ontological question had been formulated by Plato, he put the problem of Being on what was, in principle, a new basis. To be sure, even Aristotle failed to clear away the darkness of these categorial interconnections. In medieval ontology this problem was widely discussed, especially in the Thomist and Scotist schools, without reaching clarity as to principles. And when Hegel at last defines 'Being' as the 'indeterminate immediate' and makes this definition basic for all the further categorial explications of his 'logic', he keeps looking in the same direction as ancient ontology, except that he no longer pays heed to Aristotle's problem of the unity of Being as over against the multiplicity of 'categories' applicable to things.
1 '"... was einer am Seienden erfasst"'. The word 'Seiendes', which Heidegger uses in his paraphrase, is one of the most important words in the book. The substantive 'das Seiende' is derived from the participle 'seiend' (see note 1, p. 19), and means literally 'that which is'; 'ein Seiendes' means 'something which is'. There is much to be said for translating 'Seiendes' by the noun 'being' or 'beings' (for it is often used in a collective sense). We feel, however, that it is smoother and less confusing to write 'entity' or 'entities'. We are well aware that in recent British and American philosophy the term 'entity' has been used more generally to apply to almost anything whatsoever, no matter what its ontological status. In this translation, however, it will mean simply 'something which is'. An alternative translation of the Latin quotation is given by the English Dominican Fathers, Summa Theologica, Thomas Baker, London, 1915: 'For that which, before aught else, falls under apprehension, is being, the notion of which is included in all things whatsoever a man apprehends.'