One of the sciences comprised in Hume’s Science of Human Nature is metaphysics, understood as the science of the most general features of the world as it appears to us. I show how Hume’s metaphysics in the Treatise can be “methodized, or reduced to general principles.” Those principles are: (I) The Contradiction Principle: The distinctly conceivable implies no contradiction. (II) The Possibility Principle: What implies no contradiction is possible. (III) The Conceptual Separability Principle: Things are different if and only if separable in conception. On these principles the rest of Hume’s metaphysics is based, including his atomistic ontology and his denial of necessary connection: only single, individual, simple, unaltering, determinate, particular, metaphysically independent things exist.

This chapter presents a portrait of study and teaching at the Faculty of Arts in Paris during the first half-century of the university's existence: from enrolment under a master to obtaining a licence, entering the corporation of the Magistri Artium and, eventually, enrolment in one of the higher faculties (theology, canon law or medicine).

Chapter 5 explores some relations between rhetorical models for speeches in praise of the gods and Platonist texts relating to metaphysics, or ‘theology’, the science of divine first principles. As rhetoric distinguishes different modes and styles in discourse about the gods, so do the Platonists, both in their own works and in those of their ancient authorities (Pythagoras and Plato), distinguish in corresponding ways between different modes of teaching in theology. And as rhetoric prescribes, for speeches about the gods, genealogies of the gods, their actions and benefactions, so too do Platonist theological texts expound the metaphysical genealogy of first principles, a hierarchy of causes and their effects. But speech expresses the limitations of human souls: to approach what is divine and transcendent, which is ineffable, is to be silent, to practice the silence of Pythagoras and of Socrates.

Chapter 25 introduces Alexander of Aphrodisias’ systematic reading of Aristotle’s Metaphysics. I show how Syrianus took over Alexander’s reading of Aristotle, combining it with Plato’s references to a supreme knowledge, ‘dialectic’, and explaining the possibility of scientific knowledge of the objects of metaphysics – transcendent divine first principles – in terms of concepts innate in the soul which both image these first principles and are available to discursive reasoning as sources of knowledge of these principles. The primary text for metaphysics, according to the Platonists, was Plato’s Parmenides. I show how Proclus’ interpretation of the Parmenides, inspired by Syrianus, underlies the composition of Proclus’ metaphysical masterpiece, the Elements of Theology. Finally, Damascius is shown to have brought out to the fullest extent the limits of human reasonings about transcendent divine principles, reasonings which incessantly lead to contradictions and impasses, the aporetical ‘birth-pangs’ of the reasoning soul where it meets what transcend it.

The introduction to this Critical Guide offers some background to Hume’s classic A Treatise of Human Nature, originally published in three books in 1739 and 1740. The introduction then briefly broaches the debate whether Hume leaves the doctrines of the Treatise behind with his later works, and it defends the importance of the Treatise to Hume’s corpus and to subsequent and contemporary philosophical thought. It presents a summary of the fourteen critical essays contained in the volume, which include seven articles on Hume’s epistemology and philosophy of mind, six articles on the passions and ethics, and one essay on the early reception of the Treatise. Several of these essays highlight the unity of Hume’s approach in the Treatise, showing how the principles of Hume’s epistemology and psychology in Book 1 are foundational to his discussion of the passions and of morality in Books 2 and 3.

The way in which Proclus’ Elements of Theology exemplifies metaphysical science as understood by Late Antique Platonists and as expressed in Proclus’ commentary on Plato’s Parmenides is examined in Chapter 27, which proposes an analysis of the propositions and demonstrations which open the book. I stress the idea that these metaphysical reasonings were regarded as ‘exercises’ of the rational soul, a training leading to a greater proximity to divine first principles.

This chapter asks what the main currents in classical Greek philosophy understand by ‘personal religion’. How do they conceive of the beliefs and uplifting they want religious people to display? Do we have the necessary conceptual framework to understand the phenomenon of ‘personal religion’. In the study of ancient Greek religion, philosophers are often revisited to find the clearest analysis of religious concepts, though mainly in terms of the individual integrating norms of civic religion. Yet in many places the philosophers refer to those concepts and virtues in contexts outside civic religion, thus opening a broader understanding of personal religion. In connection with this the chapter also investigates what philosophers mean if they refer to their basic principles as ‘divine’. Do they introduce new divinities? Or are they introducing new ways of dealing with traditional gods? This leads to asking whether philosophical life replaces traditional religion. Very often, this is just assumed to be the case, entailing the corollary point that metaphysics comes to replace religion. Yet a case can be made that philosophers themselves avoided this merging of metaphysics and religion.

The Disputationes metaphysicae was doubtlessly an epoch-making book. Through the centuries it was read and praised not only by scholastic authors such as Hurtado de Mendoza and Gilson but also by non-scholastic ones such as Schopenhauer and Heidegger. After briefly describing the systematic framework of the work, I examine its character, arguing that not only does Suárez attempt to construct a rigorous Aristotelian science of being, but that there is also a certain dialectical character to the work that might be seen as an attempt to capture “contrary aspects of reality.” This peculiarity may at least in part explain the fact that its impact is far more difficult to assess than it is usually assumed.

This chapter explores how metaphysical models, particularly the compositional and transformational approaches, can help elucidate the doctrine of the Incarnation. While these models face challenges, such as the Nestorian and Attributes Problems, various solutions have been proposed to address these issues and align the models with orthodox Christology. Ultimately, metaphysical models aim to provide coherence and plausibility to the mystery of the Incarnation, contributing to the ongoing work of analytic theology in understanding this central Christian doctrine.

The fourth chapter examines the problem of the causality of the unmoved mover. This issue is central in scholarship on Aristotle and goes back to late antiquity. I argue that here Proclus’ non-harmonist stance towards Aristotle emerges most strongly: not only did Aristotle fail to make the intellect an efficient cause of the cosmos’ being but his metaphysics generally is deficient, since he did not recognise the Platonic One as the highest principle. I contrast Proclus’ view with the position of Ammonius and Simplicius who see a complete agreement between Plato and Aristotle.

The chapter’s first section develops the book’s underlying argument that the moral psychology of violation involves synthesising metaphysical expression and its metapsychological grounds. Its second section engages with Martha Nussbaum’s argument in Anger and Forgiveness (2016) that we should understand guilt and forgiveness without reference to metapsychology, and only in terms of unconditional love leading to eudaimonic social ‘Transition’. Against this, I argue that guilt and forgiveness remain morally important and we see this in the parable of the prodigal son. Where Nussbaum argues that the father’s unconditional love sets aside questions of forgiveness, I suggest that such moral questions between a father and son remain at stake. A third section offers a ‘case study’ of guilt and forgiveness in the dialogue between Jo Berry, whose father died in the IRA Brighton bombing of 1984, and Patrick Magee, one of the bombers. This shows how difficult moral dialogues around blame, guilt and forgiveness are central to reconciliation, though this may be blocked by surrounding unresolved social and political questions. Overall, connecting metaphysics and metapsychology enables us to see why moral transactions (distinguished from legal ones) and social transitions are both necessary for reconciliation.