Aristotle and Plotinus on the Intellect. Monism and Dualism Revisited by Mark D. Nyvlt (review)

Aristotle and Plotinus both hold that a divine, self-thinking intellect (hereafter Nous) serves as a metaphysical principle of the cosmos. However, whereas Aristotle holds that Nous is the highest metaphysical principle, Plotinus famously subordinates Nous to the One. The question that Mark D. Nyvlt pursues in this book is whether Plotinus’s subordination of Nous to the One is justified. His answer is “no.” Briefly, Nyvlt argues that Aristotle’s criticism of Speusippus’s doctrine of the One contains the response that Aristotle would give to Plotinus, and that a proper understanding of dunamis and energeia shows that Plotinus was incorrect to claim that Aristotelian Nous is infected with potentiality, and therefore cannot function as a pure principle of actuality.

Nyvlt develops this argument over the course of nine chapters that take the reader from the Pythagoreans to Plotinus. In chapters 1 to 2 he discusses Aristotle’s interpretation of the One and the Indefinite Dyad in the Pythagorean–Platonic tradition (which he refers to as the “two-principles doctrine”), and Aristotle’s criticism of Speusippus’s doctrine of the One; in chapter 3 he discusses Aristotle’s own doctrine of the one as a “pros hen equivocal”; in chapters 4 and 5 he discusses the relationship between dunamis (power, potentiality) and energeia (actuality, activity), and Aristotle’s account of the simplicity of Nous. In chapter 6 he discusses the derivation of Nous from the One and the transformation of the Pythagorean–Platonic two-principles doctrine into the Plotinian monistic doctrine; in chapter 7 he discusses Plotinus on phantasia (imagination); and in chapters 8 and 9 he discusses the influence of Alcinous and Alexander of Aphrodisias on Plotinus’s theory of Nous, and Plotinus’s account of the simplicity of Nous. Moreover, as the subtitle of the book indicates, Nyvlt focuses not only on Aristotle and Plotinus’s theory of Nous, but also on developing an Aristotelian solution to the problem of the one and the many in ancient Greek metaphysics.

The strength of Nyvlt’s book lies in its discussion of Nous in the larger context of the first principles of ancient metaphysics, and the extensive analysis of the historical influences on Plotinian Nous. Particularly helpful in this regard is his discussion of Alexander of Aphrodisias, who, according to Nyvlt, bridged the radical distance between the first principle and the cosmos with the introduction of efficient causality into Nous. However, due to the emphasis that he places on addressing the problem of the one and the many while discussing Nous, critical features of the internal structure of Nous are treated too quickly, and in some cases misleadingly. Nowhere is this more evident than in his chapter 7 on phantasia, which he includes to show that the cosmic procession and reversion take place at the psychic level and to draw similarities between phantasia and intelligible matter.

I agree with Nyvlt that phantasia functions as the center in which sensible and intelligible data converge, and that it is in virtue of phantasia that humans can consciously apprehend the activities of their soul and of Nous. However, I disagree that the activity of Nous that precedes phantasia is unconscious. Throughout this chapter, Nyvlt contrasts human consciousness with the activity of Nous, and repeatedly stresses that the activity of Nous is unconscious (see 165, 166, 172–73, and 179). However, Plotinus does not hold that Nous is unconscious but rather that Nous possesses a higher form of consciousness. For example, he characterizes the self-thinking of Nous in terms of consciousness and does so in first-personal terms: “For in general thinking seems to be an awareness [sunaisthêsis] of the whole when many parts come together into the same thing. This occurs when something thinks itself, which in fact is thinking in the proper sense” (5.3.13.12–15) and “thinking, which is prior, turns inwards towards itself, which is clearly multiple; for even...