…the foundation of philosophy has come to be seen in the supreme good and evil…all of philosophy is illuminated to the greatest degree by the recognition that virtue suffices for living happily. (Cicero, Div. 2.2)1
Casual and even systematic doubt about the reliability of anything we might “know” is not peculiar to modernity.2 Despite his practical inclinations and interests, Cicero, as a student and professed lover of philosophy, found himself compelled to consider such skepticism as part of the heritage of philosophical schools, which provided the context and basis for his own philosophical education. He encountered the skeptical outlook in various forms, actually citing on one occasion the legendary opening line of the atomist Metrodorus in his work On Nature. “None of us,” wrote Metrodorus, “knows anything, not even whether we know anything or not.”3 Cicero reveals the priorities on the philosophical agenda of the time, if not all times, when he reports in Academica Priora that Antiochus claimed that the two most important matters in philosophy are the criterion of truth (judicium veri) and the supreme end of goods (finis bonorum). An influential teacher of Cicero, Antiochus (c. 130/20–68) broke in Cicero’s lifetime from the skeptical school known as the New Academy. He is reported as having said that no one could be deemed wise who is ignorant of the principle of knowing and the end of desiring.4…be on your guard lest some wicked tribune of the people arraign you and press on you the charge of inconsistency for denying the possibility of certain knowledge and yet claiming to have some. (Cicero, Ac. 2.63; having in mind Cicero’s role as an exposer of the Catilinarian conspiracy, Catulus speaks these words to him.)
Although Cicero appears overall to share these Antiochean priorities for philosophy, he elevates the latter of the two and places the very foundation of philosophy in attaining an understanding of the supreme good and evil (fines bonorum et malorum).5 This seems to indicate that Cicero’s work on the ends, Finibus, is central to his approach to philosophy. Cicero’s brief but revealing statement on this foundation in De Divinatione is followed by another metaphor that describes virtue—that chief among goods—as the primary illuminator of all philosophy.6 Cicero’s claims, rather than being anomalous or out of character, accord with the persistent emphasis throughout this work on the priority of moral philosophy among the topics of philosophy.7 Cicero appears, then, to agree with words he puts in the mouth of Piso in Finibus, that in philosophy, when you settle the chief or highest end, you settle everything.8
Cicero does not, however, neglect the view that it is important to consider the criterion of truth. His Academica was written to manifest this consideration and address this issue, and he positions this work in his philosophical corpus to indicate its foundational importance to anything else one might seek to do in philosophy. Cicero, in fact, does more than merely pay his respect to the lively debate in Hellenistic philosophy and among his very teachers about the criterion of truth and then pass on to the knowledge that provides a direct basis for moral and political life. Cicero unambiguously associates himself with that school—the New Academy—that is especially responsible for making epistemological questions vital and important in the contentions among the schools in Hellenistic philosophy.9 According to Cicero’s account, the New Academy, which came in a later post-Ciceronian time to be known as the school of Academic skepticism, was founded by Arcesilaus (315–240) around 273B.C. and notably developed under Carneades (214/13–129/28), a later head of the Academy.10 Cicero appears to be well-informed on what these masters of the New Academy taught, and his writings are among the most important sources for information on these teachings. He studied directly with Philo of Larissa (160/59–c. 80), also a head of the New Academy. Philo, in fact, was leading the Academy when, in about 87, Antiochus caused the previously mentioned split resulting in the founding the Old Academy, yet another alleged restoration of the “true” Academic teaching that all these parties traced back to Plato and Socrates.11 In fact, certain texts of Cicero suggest that the Academy of Carneades and Philo was all but abandoned under the attack of Antiochus and others and that Cicero saw himself as one seeking to revive it.12
Cicero was immersed, then, in the strain of the skeptical tradition belonging to Carneades and Philo—that of the New Academy. Another strain of skepticism, that of Pyrrho (c.360–c.270), developed out of the Academy in the generation following Plato’s death and was revived in Cicero’s lifetime by Aenesidemus.13 Cicero may have the neo-Pyrrhonic tradition in mind when he refuses to take seriously a skepticism which he finds disabling because it undermines human responsibility by leaving man unable to know standards and goals of action.14 More likely, such comments by Cicero were directed at Arcesilaus and those Academics who were perceived as failing even to allow a standard of “probable” truth to guide action as Carneades apparently did.15 Woldemar Görler, reflecting on Cicero’s break with Arcesilaus, properly yet perhaps with some understatement, concludes, “Cicero has no great devotion to the more radical type of Academic skepticism.”16 Thus, Cicero is sometimes said to be a moderate or mitigated skeptic. His skepticism can also be called Socratic skepticism.
The problem and challenge of understanding Cicero’s philosophical foundations necessarily takes the form of understanding how Cicero thinks through his commitment to Academic skepticism in relationship to his other aspirations for philosophy, including his key conviction that fundamental to all philosophy is inquiry into the chief of human goods. Even in his lifetime, Cicero was apparently seen by some as inconsistent insofar as he professed allegiance to the skepticism of the Academy and yet sought to determine and teach moral duties.17 Understandably then, there has been a tendency at times to resolve the tension by overlooking Cicero’s commitment to the Academics, even at times to treat him simply as a Stoic.18 Cicero’s attraction at times to Stoic teachings may, however, in some way grow out of and be consistent with his underlying Academic commitment.19
Before proceeding to examine more closely the nature and limits of Cicero’s skepticism, it should be noted that the Greek word skepsis, or any Latin cognate or derivative of the word, is not in Cicero’s time in general use; nor is it used by Cicero to describe his position or that of the Academics, nor in fact is the word employed to describe that of the Pyrrhonists until the period of Cicero’s life or shortly thereafter.20 This word, which primarily and literally means “inquirer,” comes in this later time to be applied to those who make doubt about the possibility of knowing a fundamental dimension of their philosophical teaching. Academics and Pyrrhonists are, then, skeptics as we have come to use the term in the history of Western philosophy.
Cicero’s Skepticism
H.A.K. Hunt, in The Humanism of Cicero, follows Eduard Zeller in finding the history of the Academic school marked by an effort to find a criterion for choice and action. He adds, “It is natural for the Sceptic to become dissatisfied with pure scepticism and to seek some criterion at all costs.”21 The subsequent tradition of skepticism seems to support Hunt’s observation. David Hume’s thought provides, perhaps, the most widely known instance. He joins to his skepticism an effort to understand the instinct or mechanism of belief that allows him and all humans to act in the business of ordinary life.22
Deepening our understanding of Cicero’s skepticism calls for attention to how he lives with his skepticism,23 to what is his “criterion for choice and action,” to how he responds, in other words, to that first of the two key questions of philosophy which Antiochus highlighted: the one concerning the criterion of truth. What, then, is Cicero’s way of determining the reliability of any perception and any assertions so as to allow meaningful human communication and action? Given Cicero’s commitment to political action and leadership, one expects that he would strongly seek to avoid the often alleged socially and politically disabling aspects of a pure or even a strong skepticism. And as already suggested, one is not disappointed in this expectation. Just as clearly as Cicero associates himself with the school of the New Academy and the skepticism of Carneades and Philo, so too he embraces the criterion that they apparently utilized and thus limits his skepticism.24 As Cicero states in Finibus, his philosophical “affiliation” with the New Academy allows him to approve and accept those matters that seem probable (ea quae probabilia videantur).25 The probable for Cicero is the likely true (simile veri).26 At times, Cicero conjoins these expressions (probabile et simile veri) in describing his criterion as an Academic.27 Insofar as Cicero and the Academics allow, if not encourage, the inquirer to approve and accept (probare or adprobare are the terms used) a perception or proposition that is simile veri, they provide the basis for a clear, if elemental, understanding of the concept “probable” as used in an epistemological sense: The probable is literally that which is able to be accepted (approved) as likely to be true.28 Thus Cicero effectively accepts as true, not however as certain and beyond philosophical doubt, whatever is probable. In Academica and speaking through himself as persona, Cicero insists that action and life can proceed quite satisfactorily with “nothing to follow but probability” because so many significant actions like going on a voyage, sowing a crop, marrying a wife, and procreating children already and manifestly rest on probability.29
Closely related to this last statement is a conviction of Cicero that is evident on several occasions where he is found discussing the criterion of probability. This conviction entails a claim that is, for instance, present in the previously cited passage in Fin. 5.76; Cicero’s criterion of probability is there imbedded in a rhetorical question, “For who is able to refuse acceptance of those matters that appear to him probable?” (Quis enim potest ea quae probabilia videantur ei non probare?). Probability determinations are, thus, seen as instinctual or automatic. They simply spring from the way we ordinarily live—one might say, from the way we are. Cicero has apparently translated into “probabile” the Greek term pithanon which Philo and Carneades had used to designate the criterion.30 That term is customarily rendered in English as “credible,” “convincing,” or “persuasive.” It is not clear why Cicero chose “probabile” rather than “credibile” which was available to him to represent this key concept of the New Academy.31 What is noteworthy is that the probable for Cicero, like pithanon prior to him and belief as operative much later in Hume’s thought, overtakes one in the course of the practice of ordinary life.32 The limits of skepticism are found in ordinary practice, but the intervening hand of philosophical doubt is evident insofar as the criterion comes to be described as the probable, the convincing, or the believable rather than the known...