The significance of traditional theoria to the philosophical thought of Plato and Aristotle is indisputable, reflecting the central role that the practice plays in the two philosophers’ accounts of theoria. Plato makes explicit, and sometimes ironic, use of the tradition at several levels in his dialogues. To mention one example, in Rep. VI we find Plato mentioning and then re-conceiving theoria – first, he takes it as festival-attendance, which he describes as akin to mere dreaming (Rep. 476b1–5) – and then he transforms it into genuine philosophical inquiry. Yet, the Platonic ideal of philosophical study preserves various features characteristic of traditional theoria including its observational component, its religious objective, and its cosmopolitanism.

For approximately the last thirty years, Cicero’s reputation as a philosopher has been rising after close to a century of very low esteem. The alleged reasons for this disrepute are numerous and varied. Cicero was Roman, and Romans were thought to be neither scientific nor philosophical. He wrote in Latin, when the genuine language of philosophy was and is Greek. No original thinker, he was not so much a philosopher as translator and compiler, pasting together various philosophical works from the second and first century bce. This he did in his spare time, for Cicero was an amateur philosopher. His main pursuits were politics and judicial advocacy. When he turned to philosophy, he was content to adopt a form of eclecticism amenable to his own changing status in the troubled last decades of the Roman Republic. This short introduction won’t be covering Cicero’s philosophical works and their context (for which the reader should consult Chapter 1); it aims only to present the various and complementary ways in which this Companion, building on earlier studies, may answer these charges and allow us to gain a more accurate and richer picture of Cicero as a philosopher.

Cicero conceives of rhetoric, politics, and philosophy as so interconnected that they are, or at least should be, a unity under the rubric “eloquence.” To be sufficiently capacious to include all three, eloquence means something different to Cicero than to us, with its current meaning of fluent or persuasive expression. Rather than simple (or even outstanding) facility in language, eloquence for Cicero is public speech, especially political speech, rooted in wisdom. Cicero, most especially in his rhetorical masterpiece, De oratore, deems the eloquens, the man of (true) eloquence, to be the perfect orator, who is simultaneously the ideal statesman, articulating his ideas in words so powerful that he can move his audience in whichever direction he so desires. Because of the danger inherent in such forceful persuasion, the eloquent orator must apply his rhetorical skills only after having acquired “all-embracing knowledge.” Thus, Cicero’s orator-cum-statesman is also a philosopher of a sort – a philosopher who is a man of action, who uses his wisdom to promote the common welfare, unlike those philosophers who shirk “politics and its responsibilities on deliberate principle,” and who criticize and scorn the orator-statesman’s practice of speaking.

The introductory chapter explains an initial problem concerning the ambiguous application of the term 'theoria' both to the practice of festival-attendance and to philosophical study, or contemplation. While the two referents appear to have little in common, a closer examination reveals a common feature of theoria, namely, the idea of observing, or beholding, something divine or of high significance. The notion of acting as an observer of the divine, or like a divine spectator, serves as central common element running throughout the kinds of theoria and allowing us to understand why Plato and Aristotle chose to borrow a term referring to festival-attendance to signify what they describe as an activity of our highest capacity, the mind.

The first chapter is focused on central features of traditional theoria which is a practice of attending festivals and sanctuaries; we consider the duration of the practice over several centuries as well as its geographical spread over the Mediterranean area. The primary characteristics of the traditional form relate to attendants traveling from home to foreign sites, such as Olympia or Athens, to observe and participate in the several periodic religious festivals that support the political and religious civic institutions. By fostering shared ideals of moral and intellectual values, traditional theoria also contributes to a form of Hellenic cosmopolitanism connected to Greek philosophy.

In this chapter I try to strengthen the results of the preceding chapter by looking at how Aristotle attempts to negotiate the issues identified there: whether knowledge is [1] “like by like” and [2] “alteration.” I argue that this is the work of De Anima II 5, a difficult text which has attracted a considerable literature, much of it animated by the question of whether Aristotle conceives of perceiving as something purely “spiritual.” Though I argue (as have others) that this question is not settled by II 5, my primary object is to present a reading on which its main business is to clarify the “grammar” of perception, so as to respect the fact that perception is of beings without rendering that fact unintelligible in principle. I argue that what the chapter says about the way perception is (and is not) a kind of alteration, and about the way it is (and is not) like by like, is as though designed to secure it that knowledge of beings is a fact that has causes.

Aristotle maintains that defining "intelligence" (nous) requires first defining its activity, “understanding” or “insight” (noēsis) which requires first having considered its objects, intelligible beings (noēta). This chapter is about the nature of these objects: what about them makes them intelligible? My principal proposals are that what makes them intelligible is that they are "separate" and "unmixed," and that because, insofar as they are intelligible, they are, in their essence, "activity."’ I am aware this makes it sound as though Aristotle takes intelligibility to consist in some kind of intelligence. But in fact this is a result he is committed to, by the doctrines that intelligence is intelligible and that there is something that intelligible objects "all are in common"; for the alternative, as he himself says, is to suppose that intelligence "will have something mixed-in, which makes it intelligible just like the rest." The challenge, then, is not to steer clear of this result, but to make sense of it. My proposal is that the key to this lies in realizing that and why Aristotle thinks of intelligibility as a creature of intelligence.