  Numenius, then, distinguishes two sources of reality, or two ontological principles, God-the Good and matter (inspired by Timaeus 47e-48a and Aristotle's report about Plato's principles in Metaphysics 988a7–15). Yet the crucial question for Numenius was how one should think about this divine principle, the Good, what kind of God this is. Numenius' position on this has much to do with his view on matter. Numenius advocates a strong dualistic position. In this he is like Plutarch and later Atticus follows them.  Numenius' dualism is different from that of most contemporary Pythagoreans we know of, like those referred to by Alexander Polyhistor (in Diogenes Laertius VIII.25), by Sextus Empiricus (Against the Mathematicians X.261–2), by Nicomachus of Gerasa (Theologia Arithmêtikê in Photius, Bibliotheca cod. 187, 143a24), by Eudorus (Simplicius, In Physica 181.10–30) and by Moderatus (Porphyry, On Matter in Simplicius, In Physica 231.6–24). Those Pythagoreans postulated God or One, on the one hand, and matter or the indefinite dyad, on the other, but they maintained that God or One is the ultimate principle of everything (Simplicius, In Physica. 7.1–30); from this matter came into existence through the total privation of form (ibid. 231.7–9). Numenius appears to be reacting against this view, which is associated specifically with Moderatus (fr. 52.15–23; see Kahn 2001, 133). Numenius rejects Moderatus' view in favor of his own dualistic position, presumably because he wants to avoid the implication of the monistic position that God is the source of what is bad. This concern seems also to motivate Numenius to distance God from matter as much as possible. He thus distinguishes the divine demiurge, who creates the physical world by imposing order on matter, from the highest God. This highest God is metaphysically above the demiurge (frs. 16, 17, 19–21) in the sense that the highest God, which Numenius also calls the first intellect (fr. 20.12), is inert (fr. 12.13, 15.2) and utterly simple (fr.  11.11–14), qualifies as being itself (auto on; fr. 17.4) and the source of being (fr. 16.4–5, 9), while the demiurge is the source of generation (fr. 16.5); the highest God is absolute goodness (frs. 16.4, 9–10, 20.12), identical with the Form of the Good (fr.  20.5, 11). Unlike the Form of the Good in Republic VI, however, that is beyond being, Numenius' first God is being, and indeed the source of it. This is not at odds with the Republic, however, since several passages in it describe the Good as being (518c9, 526e3-4, 532c5-6; see Burnyeat 2005, 154-155). Numenius apparently takes stance in a debate among Platonists as to whether the first principle is being or beyond being (Origen, Against Celsus IV.64.14-28). Numenius actually describes the First God as being (ho ôn), a phrase that alludes to Exodus 3.14 (fr. 13.4). This Biblical reference has been much debated and a number of alterations of the text have been proposed (see Dodds 1960, 15-16, Baltes 1975, 262, Dillon 1977, 368, Tarrant 1979, Edwards 1989). None of these proposals is however convincing since Numenius frequently designates the first God as being (frs. 5.5-14, 6.7-8, 8.2; see Whittaker 1978, Edwards 1990b, 21-22, and also Burnyeat 2005, 149-162). Yet this first God that is identified with being and absolute goodness, remains “alone, isolated, abandoned” (fr. 2.9),which suggests that this God, like Plotinus' One, is ineffable and incomprehensible (see Whittaker, 1993). Numenius thus sets himself apart from those Platonists who identified the divine demiurge of the Timaeus with the Form of the Good of Republic VI (508e), but his view is adopted by Alcinous (Didascalicus ch. 10, 164.27–165.16 Hermann), who must be writing some decades later than Numenius.