Eight years ago, I reviewed L.P. Gerson, From Plato to Platonism (2013) in the Notre Dame Philosophical Reviews (2014.10.07). There I welcomed Gerson's thesis for what he calls ‘Ur-Platonism’, an abstract construct of the five quintessential ‘antis’ (anti-materialism, anti-mechanism, anti-nominalism, anti-relativism and anti-scepticism), that provide the matrix of all forms of Platonism, from Plato to Plotinus, in Wittgenstein's sense of ‘family resemblance’ (pp. 9–19). There I also wished for a DNA type of genealogical search, tracing and uncovering the roots that nurtured and propagated the different strands of Platonism in a system of relations that recognises the intermediaries’ contribution to the formation of Neoplatonism as the main root, sustaining the longevity of Platonism throughout the ages. D.'s volume fulfils that wish.

The pithiness of the book is striking, and so is its eclecticism. The 95 pages of the main body of text contain six chapters, presenting in a more developed form six lectures, delivered in master classes on ancient Greek philosophy at Renmin University in Beijing in 2016. In addition, the last four lectures (Chapters 3–6) gather pieces published in different venues in the period from 2011 to 2018. Each of the four works addresses a key issue that has challenged scholars of Platonism: the relation between the Demiurge and the Forms in the Timaeus (Chapter 3), the hierarchy of being as a framework for Platonist virtue ethics (Chapter 4), the limits of Platonist epistemology in Carneades (Chapter 5) and the defence of Socrates’ aporetic tradition in Plutarch (Chapter 6). D. embeds the above issues of metaphysics, ethics and epistemology in his opening discussion of the origins of Platonist dogmatism (Chapter 1) and monist and dualist tendencies in Platonism before Plotinus (Chapter 2). In the introduction he embraces the eclectic structure of the book and clarifies its goal as not aspiring ‘to provide here any sort of definitive study, but rather a contribution to the on-going debate as to the nature and origins of the Platonist tradition’ (p. 6).

There is something disarmingly Socratic in D.'s modest goal on the background of his long, distinguished track, shaping the study of Platonism since 1969. At the onset of the book he acknowledges that he has nursed ‘for some considerable time’ his interest in ‘the process by which the intellectual speculations pursued by Plato … came to assume the nature of a philosophical system’ (p. 1, author's emphasis). He pinpoints the appearance of his paper ‘Self-Definition in Later Platonism’, published in the edited volume Self-Definition in the Greco-Roman World, in 1982 as marking the beginning of his interest in the factors and the mechanism by which a philosophic movement defines itself formally. Six years later, in 1988, the topic is further explored in his contribution ‘“Orthodoxy” and “Eclectism”: Middle Platonists and Neopythagoreans’ to the edited volume The Question of ‘Eclectism’: Studies in Later Greek Philosophy. The two examinations establish the general framework according to which a conceptual movement seeks to define itself as an ‘orthodoxy’ in a defence or an attack against rival movements, polemically labelled as ‘heresies’. His subsequent studies of well and lesser known figures of philosophic import collect mountains of evidence regarding the conceptual developments, bearing fruit in the different strands of Platonism from Plato's successors in the Academy to its last scholarchs. It is only natural that, after continuous and exhaustive studies, D. revisits his original interest in how the views, espoused in Plato's dialogues, become the philosophical system of Platonism, this time considering the salient ideas that have been transmitted.

D. frames his investigation in the context of Gerson's five antis, mentioned at the beginning of the review, but sets to examine their content in the opposite direction (p. 3). As restated in his conclusion, ‘I can formulate my purpose here as being to demonstrate how, without abandoning those principles [the five antis], Platonists after Plato proceeded to construct a series of positive positions, in the areas of metaphysics, ethics and epistemology, on their basis’ (p. 94). D.'s approach complements Gerson's reconstruction of a set of five abstract principles, by teasing out the content of the Platonist world view as an open-ended undertaking, comporting with the growing number of new trends in the studies of Platonism today.

The key issues D. turns his attention to cover the full range of Platonism (metaphysics, ethics and epistemology) during the formative period of the Old, Middle and New Academy. Beginning with the origin of Platonist dogmatism, Chapter 1 traces it back to Xenocrates’ tripartite division of Plato's views into physics (and metaphysics), ethics and logic. This compartmentalisation naturally lends itself, D. concludes, to the distilling of ‘first principles’ in each division. The subsequent five chapters address issues surrounding the first principles of physics and metaphysics (Chapters 2 and 3), ethics (Chapter 4) and epistemology (Chapters 5 and 6). In the area of physics and metaphysics, Chapter 2 examines the oscillation between monistic and dualistic tendencies in the Platonists’ views before Plotinus, characterising Plato as ‘a modified monist’ at the one end of the pendulum (p. 34) and Xenocrates as a proponent of ‘modified dualism’ at the other end (p. 30), with Plutarch's extreme dualism as an outlier (pp. 31–2). A more focused metaphysical issue (Chapter 3) is the relation between the Demiurge as the primary cause for the organisation of the world order and the Forms as both the paradigm of his organisation and its content. D. uncovers the origin of the idea of the Forms as thoughts of God in (1) the Stoicising influence on the Platonism of Antiochus of Ascalon, (2) the de-mythologisation of the intelligible living being in the Timaeus 30c–31b in a vertical series of relations between the Forms and God, humankind, the sensible world and their essences, found in Alcinous, and (3) the postulate of the One as prior to Intellect, propounded by Plotinus. In the area of ethics, Chapter 4 turns to the delineation between the Stoicised understanding of living in ‘concordance with Nature’ and the later Platonist view of ‘assimilation to God’ (p. 52). D. identifies the origin of the notion of degrees of virtues in the notion of hierarchy of being, first detected not until the second century, in Numenius’ distinction between a primary and a secondary God (p. 59). In the area of epistemology D. addresses two key issues in the sceptic turn of the New Academy. The first (Chapter 5) is Carneades’ distinction between living life rationally by acquiring a high degree of belief on certain topics and remaining aloof on the question of knowledge (p. 78). The second (Chapter 6) is Plutarch's attitude towards current philosophic developments. Unlike many of his contemporaries, D. argues, Plutarch considers the sceptic outlook of the New Academy an integral part of the Academy after Plato and himself adopts its aporetic method in many of his works. On this question and throughout the book, D. often modifies positions he has previously held on what he calls ‘a maturer consideration’ (p. 79). This by itself is one of the many exemplary aspects of the book. Leading among them is how much ground is covered by its pithiness.

The Roots of Platonism is D.'s gift of wisdom to the ongoing study of the origins of Platonism, told in a delightful style, philosophising through vignettes on G. Vlastos's epistemological self-examination of why he has quit smoking and Socrates’ walking out from the wrong bar in Dublin. Without claims for definitiveness, D. has opened new vistas for exploration. The cup of Platonism is always half full for him.