This book has looked at some familiar doctrines from a different perspective. The doctrines were that sensibility is a kind of mean and that intelligence is something single, separate, unmixed; the perspective was to see these doctrines as filling out Aristotle’s explanation of why it is in human nature to perceive and to understand beings. The core of that explanation is that sensibility and intelligence are “forms” or “measures” of their respective objects, perceptible and intelligible beings; to see the doctrines just alluded to as “filling out” this core is to see them as specifying those forms or measures (in the one case as a kind of mean, in the other as something simple, separate, or unmixed). The upshot is that there is a kind of priority of sensibility and intelligence to perceptible and intelligible beings. Some will find this upshot un-Aristotelian: doesn’t he hold that perceptible and intelligible beings are causes of and (therefore) prior to perceptual and intellectual knowledge? In this concluding chapter then I try to meet this and similar concerns, by way of clarifying the perspective I have been developing.

Aristotle represents many of his predecessors as having arrived at their views about psuchē from reflection on the fact that knowledge is of beings; it is this fact, together with the principle that knowledge is “like by like,” which led them to the view that psuchē is an amalgam of the elements of all beings. But though Aristotle thinks little of this view, he accepts the considerations (duly qualified) from which it is derived. Now, the principle that knowledge is “like by like” is an explanatory principle; it locates the “cause” of knowledge in an antecedent likeness between its subjects and objects. Moreover, analogous principles have been offered to explain analogous facts, and they too are principles which (duly qualified) Aristotle accepts. But though we might expect the qualifications to vary from case to case, still we might wonder whether there isn’t some point they all enforce. In this chapter I argue there is such a point: that the explanatory “likeness” between the parties in question is never just any likeness, such as obtains “as it happened” or by chance, but is always an antecedent likeness in some form common and natural to all parties involved.

In this chapter I argue that Aristotle is seeking, in the De Anima, to explain why it is in human nature to know beings (all beings). The argument rests in part on how Aristotle introduces his agenda and in part on a criticism he makes of his predecessors. I also discuss various qualifications that must be made to that introduction and that criticism in order to bring them in line with Aristotle’s considered views.

The most obvious use of philosophy within Cicero’s speeches is as a source of invective: Stoicism against Cato in the Pro Murena, Epicureanism in In Pisonem. However, even here Cicero is careful to show that philosophical adherence itself is not a fault; but only faulty adherence. Elsewhere in the speeches, Cicero draws on Stoic theories of society in constructing his views of the relationship between the res publica, crisis, and tyranny and in articulating the justification for tyrant killing: this line of argument can be traced from the Catilinarians through Pro Milone down to the Philippics.

In his treatises De divinatione and De fato, Cicero discusses the possibility of the prediction of future events. His understanding of divination in these philosophical works differs significantly from accepted Roman practice. Thus, De divinatione should not be read as a handbook on Roman divination. Rather, it should be read alongside De fato as an exhortation to act in the service of the res publica after the death of Caesar. Rather than denying outright that divination is real, Cicero seeks to refute the more superstitious divinatory practices current in Rome, all of which he attaches to the individual rather than to the political community to which he has dedicated his life. Among these superstitious views are the belief that humanity is subject to impersonal fate and therefore that human responsibility is curtailed. In writing for a Roman audience, Cicero denies both the notion that men cannot be responsible for their own actions, thus rejecting the idea of fate, as well as the existence of divination in the context of a deterministic worldview.

This chapter aims to examine how Augustine appropriated Cicero’s philosophical thought. The first section studies the role of the Ciceronian protreptic Hortensius – the eudaimonism and the post-mortem destiny of the soul – in Augustine's philosophical project. The second analyzes the imprint of the philosophical dialogues of Cicero on Augustine’s early “Dialogues of Cassiciacum” (Contra academicos, De beata vita, De ordine, 386 ce); this influence is obvious in their literary genre and in the major philosophical topics they deal with (epistemology, ethics, providence). In his late masterpiece the City of God, Augustine discusses several Ciceronian notions (fate and foreknowledge; populus and respublica; passions) and translates them into a Christian framework: this is the focus of the third section. The last section outlines the evolution of Augustine’s judgment on Cicero, whom he considered a defender of the Neo-Academic position on the one hand, and, on the other, as a spokesman for Platonic philosophy.

Cicero bequeathed to later political thought influential accounts of cosmopolitanism, empire, and just war theory. This chapter examines these themes in his De republica, De legibus, and De officiis. I argue that Cicero’s discussion evinces a nuanced and sensitive treatment of the universalism characteristic of the natural law cosmopolitan tradition and the particularism of the republican tradition. Cicero’s theorizing shows a greater coherence than most modern scholars suppose. Ultimately, his “patriotic cosmopolitanism” offers a rich response to a question of immediate importance in contemporary politics, where the place of the nation in our global order is hotly debated: how may our allegiances to our particular political communities square with our aspirations for global justice? For readers interested in “international relations,” Cicero remains good to think with.

Plato was for Cicero the prince among philosophers. Cicero himself identified with Plato in all his richness and abundance as a writer and thinker, but also as a model for the politically engaged intellectual. This chapter studies first Plato’s presence in Cicero’s letters in the period 54–49 bce, the tempestuous years before the Roman Republic was finally torn apart. Then it turns to consider the three major Platonic dialogues composed at that time: De oratore, De republica, De legibus, in which he articulates grand political and cultural ambitions for the orator and a vision of how a republican polity should and could be conceived and conducted. A brief final section looks at the theoretical writings on oratory and philosophy in 46–44, mostly composed during Caesar’s dictatorship, when Cicero’s voice in the public sphere was almost entirely silenced. His main literary efforts were devoted to the construction of a philosophical encyclopedia, in which the systems of the Hellenistic schools became the main focus. His veneration of Plato and his attraction to Platonic idealism in various aspects remain evident. But the intensity of his earlier engagement with Plato has become a thing of the past.