As a preliminary to discussing the idea that, for Aristotle, sensibility and intelligence are “measures” of their respective objects, in this chapter I discuss Aristotle’s conception of “measure.” Though the devil is in the details, the fundamental point is tolerably clear. It is that measures for knowing the objects of some genus are prior to – enter into the very idea of – certain particular forms of that genus. The inch, for example, is a measure of length, and it enters into the very idea of certain particular lengths, e.g. one inch, two inches, three inches, and so on. Similarly, if straight is the measure of linear shape, it enters into the very idea of certain particular shapes, e.g. straight and curved. In this way and in this sense, measures are “forms of forms”: that is, what it is to be certain particular quantities or qualities of a genus is to stand in some relation to the “measure” of that genus.

In the face of current perplexity and debate about the nature of the republican tradition, this chapter recalls and more fully recovers the republican aspects of Cicero’s political philosophy. The creators of the American Republic, especially John Adams, and many others including contemporary scholars, have looked to Cicero as a major figure, if not the founder, of the republican tradition. Analysis of Cicero’s definition of res publica provides the basis for an interpretation that at its core is consent, not necessarily formal and explicit, implying liberty. To be fully human is to be free, and to be free is to be a consenting partner in a political community that is just and at liberty to set its own course. A dynamism toward equality coupled with the necessary wisdom and virtue and their implication of inequality are also essential to Cicero’s republicanism. These essentials are to inform institutions and practices. The practical wisdom in institutions includes the rule of law, indirect rather than direct popular government, and mixed government. Roman (and thus Ciceronian) republicanism can be differentiated in some respects from that very self-conscious and much-heralded form of republicanism that developed in the America of John Adams.

The chapter seeks to identify the triple historicity of Cicero’s relationship to philosophy. The first part presents Cicero the historian, who sought to clarify the history of philosophy and its reception in Roman society, as well as to analyze the resistance of his contemporaries to the practice of philosophy, which was considered incompatible with political action. The second part describes the intellectual revolution, under the designation of “reason,” which some of the Roman elite developed as a remedy to the crisis of the Republic; Cicero appears there as the witness par excellence of this intellectual experience in the service of the city. The third part of the chapter examines Cicero the philosopher himself, actor of this revolution. The analysis of his work allows us to see the multiple facets of this man who was also reader, translator, and disseminator of texts and ideas, and to identify his place in relation to his literary milieu, and in particular to his friend Varro.

In this chapter I develop the point that the knowledge Aristotle particularly wants to explain is knowledge of beings. I work from certain problems he thinks prevented his predecessors from defining psuchē satisfactorily. I focus on two issues in particular: whether knowledge is “like by like” and “alteration.” I argue that the problem raised by both issues is at bottom the same. If knowledge is alteration, and is “like by like,” the result is that our knowledge is so colored by arbitrary facts about us as to belie the idea that it is really of beings as they are “in themselves.” If knowledge is not “like by like,” and leaves its subjects unaltered, the result is to make it unintelligible in principle why subjects of knowledge have anything to do with its putative objects. In short, the problem is how to respect the fact that knowledge is of beings, as they are in their own right, without rendering that fact an inscrutable mystery. For these points I rely on De Anima I 2, III 3, and Metaphysics G 5. These texts combine to establish that, for Aristotle, the outstanding representative of the problems in this area is Protagoras.

The prefaces of Cicero’s late dialogues indicate that they share a pedagogic function with the philosophical practices of the Hellenistic Academy. In the first part of this chapter, we give a few examples showing how the late dialogues serve this end, and use them to argue that Cicero’s texts systematically enact, as well as represent, an Academic pedagogical methodology. In the second part of the chapter, we use these results to propose that Cicero’s earlier, “Platonic,” dialogues are equally sophisticated in the modes through which they effect Academic aims concerning philosophical education. As starting points for further inquiry, we indicate a few of the devices the early dialogues employ to prompt the reader to reflect on her job as a philosophical critic.

The fourth chapter examines Aristotle's distinctive contribution to the history of theoria, one which develops Plato's idea of an intellectual activity aimed at the apprehension of form, concluding it counts among the highest human activities. In many ways, Aristotle would concur with Plato's rejection of traditional theoria as a pursuit practiced by unphilosophical, doxastic believers. Leaving aside a negative critique of the practice, his own treatment emphasizes the great intellectual potential afforded by philosophical theoria. For Aristotle, this activity consists in a specific kind of thinking he connects to scientific understanding; in other aspects, he compares the activity to seeing, describing the performance as divine, or god-like, in its nature.

Cicero’s epistolary corpus is still partly unexplored from a philosophical angle. Modern scholars have left aside discrete and fragmentary allusions to philosophy, though the letters are a laboratory in which the origins and the development of Cicero’s thought appear more clearly than in his later works. The study of Greek words loaded with philosophical connotations, especially when these words are not translated, is particularly enlightening from this point of view. In this chapter, I successively study three different uses of philosophical Greek in Cicero’s letters: (1) Greek language betraying the influence of a philosophical model on the letters (the influence of protreptic) long before the Hortensius was written in 45 bce; (2) Greek language coming from implicit quotes, whether they serve a purely philosophical purpose or interweave philosophy and literature; (3) Greek language revealing the progressive elaboration of a philosophical work, De finibus, and its analysis of the Stoic theory of οἰκείωσις in book 3.

The second chapter examines literary and historical sources writing about theoria, including those by Herodotus, Thucydides, Aristophanes, and Euripides, as a means of providing the larger cultural background against which Plato's use of theoria must be considered. Two analogies to traditional theoria are here considered, that of pilgrimage and cultural sight-seeing, both of which contribute elements to the distinctive intellectual conception of theoria developed by Plato and Aristotle with which the chapter concludes.

The fifth chapter provides a synoptic chapter about the objects of theoria, both as they relate to traditional theoria and to philosophical theoria. The objects of the former kind of theoria, namely, festival- and sanctuary-attendance, are the images of the gods on temples or the gods themselves. In the case of philosophical theoria, or contemplation, the objects are more abstract entities, namely, forms, that Plato and Aristotle take to comprise the highest objects of philosophical study, or contemplation. The philiosophers consider that when we apprehend these objects, we are in possession of scientific knowledge that they compare to divine activity. In both kinds, the apprehension of the objects of theoria is reached through an activity that is directly perceptual or mediated by perceptual experience.

This chapter provides a critical account of Cicero’s discussion of the nature of the soul and the emotions in the Tusculan Disputations. The first two sections trace the key steps of Cicero’s argumentation as he critically evaluates the strengths and weaknesses of various competing views in the Greek philosophical tradition. Cicero ultimately purports to favor Plato’s position on the immortality of the soul and the Stoics’ cognitivist account of the emotions. The final section draws attention to the ways in which Cicero employs and evaluates these philosophical resources in the realm of therapeutic practice, as he reflects on his own experience of suffering and loss. Cicero showcases the practical utility of a flexible therapeutic model that focuses on the transformation of beliefs: while he clearly favors the Stoic explanation of the emotions, he does not feel compelled to recommend only the therapy in agreement with that explanation. This pragmatic approach can be seen as a distinctive aspect of Cicero’s own philosophical practice.

Cicero’s De natura deorum, De divinatione, De fato, and Timaeus offer a coherent development of some of the questions first raised in De republica and De legibus. In the specific context of the mid-first-century bce debate between Stoics and Epicureans, Cicero raises three far-reaching issues: can a rational discourse on religion be developed without a solid cosmological and theological foundation? What use can be made of historical and anthropological observations of cultual practices? Is it possible to reach a universal definition of the psychological process which accounts for human attitudes towards the gods? Cicero’s authorial strategies frame skeptical arguments so as to suggest constructive answers and preserve human freedom and moral responsibility. A mythopoetical discourse on the universe offers sufficient background as “provisional physics.” Historical enquiries help define precise limits for political thinking on religion. Philosophy explains psychologically how the admiration for the beauty of the world leads to ethical accomplishment.