The introduciton opens my exploration of Cicero’s notion of will. I argue that the will is an original Latin contribution to the Western mind. Cicero’s letters, speeches, and treatises show how his skill for language gave him a subtler take on events and a richer repertoire of persuasion. Practical uses of will are foremost: mapping alliances, winning elections, and navigating the “economy of goodwill.” From his earliest writings, however, voluntas emerges in normative claims about law and politics: that Rome’s mass of precedents could be rationalized through Greek ideas. Chief among these is Plato’s precept that reason must rule, and thus an alliance of philosophy and tradition can save the dying Republic. Transmuting political failure into philosophical innovation, Cicero lays the foundation for an idea – the will and its freedom – with tremendous consequences for Western thought. For Cicero, voluntas populi becomes the binding force of a nominally popular but functionally aristocratic constitution. If this state of affairs looks familiar in today’s “democratic” republics, we have Cicero in part to thank. Insistence on the singularity of popular will and mistrust of the common citizen lie at the heart of today’s political crisis and will require Ciceronian creativity to fix.

This chapter draws on Cicero’s letters to propose the existence of an “economy of goodwill” in the late Roman Republic. Through voluntas mutua, the mature statesman handles sensitive transactions and vouchsafes his allies’ support. I examine potential antecedents to Cicero’s goodwill in Aristotle’s theories of friendship (eunoia and philia), as well as in the system of “friendly loans” (mutuom argentum) in the comedies of Plautus. Cicero’s economics of friendship, though informed by these others, aim at problems particular to Rome’s fast-growing empire. Unlike normal currency, “spending” voluntas only increases one’s supply of it, allowing for mutual reinforcement of political support over time. Additionally, voluntas may be exchanged regardless of facultas, facilitating long-distance governance by low-cost trades of support across the empire when concrete beneficia are unfeasible. In his philosophical works, finally, Cicero shows an intriguing ambivalence about the economy of goodwill that served him so well in practice. Are reciprocal favors a defensible part of friendship? Though he excludes the possibility in De amicitia, in De officiis, voluntas mutua is redeemed in decorum, the ideal by which proportion and mutuality yield virtue.

This chapter is dedicated to the theory of selfhood Cicero presents in the De officiis: each person being a player of four personae. The allegory of four dramatic roles or masks (from the Greek prosopon) is borrowed from the Stoic Panaetius, whose ethical theory adapts the stringent demands of the sage to a morally imperfect and multifarious public. He who wishes to progress, Cicero explains, must play the roles of reason, of nature, of fortune, and, finally, the role “we ourselves may choose sets forth from our will” (quam personam velimus, a nostra voluntate proficiscitur). In this final treatise, the will comes most clearly into view as a mental capacity and rational force. I argue that when read in conjunction with related uses of voluntas and persona in other texts, Cicero’s will serves a recursive purpose within each of the other personae. Whether in actualizing reason, refining our inborn qualities, or navigating the forces of necessity and civic duty, voluntas creates a dialectic of actor and mask from which emerges a conscious moral self. Though the will develops richly as a moral faculty and principium individuationis in the hands of later thinkers, its terrestrial purposes disappear as divine ones take hold.

With the Tusculan Disputations, willpower enters Western thought. This chapter departs from a peculiar decision Cicero makes in his account of the human soul. In previous centuries, Platonists and Stoics had bitterly disagreed on whether the soul was unified or divided into rational and nonrational parts. In the Tusculan Disputations, Cicero announces that he will combine Stoic moral stricture – predicated on the soul’s unity – with Plato’s divided, self-moving soul. The result is a new narrative of inner struggle in which voluntas gains a formal definition at last: “that which desires with reason” (quae quid cum ratione desiderat) (Tusc. 4.12). While drawing importantly on the Hellenistic schools of philosophy, the Latin “force” of volition is foremost. Here, Cicero links together lines of debate that in Greek had run in parallel, rendering hekon, boulesis, and prohairesis by voluntarius and voluntas. His “struggle for reason” thus moves originally beyond Greek accounts of askesis, moral training that emphasized education and cognitive clarity over present effort. An orator zealous to persuade, Cicero paints his account of reason in Roman colors of honor, endurance, and painstaking progress.

In this chapter, I examine how voluntas helps the young lawyer Cicero craft arguments and structure relationships with Roman clients, witnesses, and juries. In the De inventione and forensic speeches, we see his struggle to reconcile tradition with new intellectual tools. As he seeks to bring ratio more fully into Roman legal culture, voluntas plays a plural and ambiguous role. It is an instrument of rational inquiry, as in the competing schemata of criminal responsibility he examines in the De inventione. As it has always been in Roman law, voluntas is the desire of a legally relevant individual, emanating from and attributable to him alone – the marker of his agency and responsibility. So, too, however, is it used to signify the collective goodwill of an audience, which Cicero makes clear is the expert orator’s plaything. The “goodwill” sense of voluntas adds greatly to its durability in moral philosophy. While a sententia or iudicium pertain to a specific question, voluntas marks an ongoing choice or disposition, such as the will of a legislator, to be conserved. Cicero’s objectives for the law go largely unachieved in his time, but they expand Rome’s intellectual field of vision.

Chapter 5 presents the subject matter of artificial intelligence, focusing on machine learning, where these machines are artificial agents. It presents simple examples of unsupervised learning, supervised learning, and reinforcement learning, and introduces notions of dynamic programming, Q-learning, and stochastic control. After that, it explores some links that can be established between artificial intelligence and the philosophy of mind, presenting and discussing the Turing test, the philosophical approaches of eliminativism and functionalism, and the problem of tacit knowledge.

In this chapter, Guido Kreis discusses the key concepts and arguments of Cassirer’s philosophy of mind. Kreis argues that for Cassirer, the mind is non-atomistic in the sense that mental occurrences are always already “symbolically pregnant” with significance. This leads to a functionalist model of the mind, which understands the mind as neither a physical body nor a metaphysical substance but rather the system of our representational contents. On the one hand, Cassirer criticizes the attempts at a physicalistic naturalization of the mental. Kreis considers this critique in view of the normative dimension of judging and the representational content of recollection and memory (when directed against Bertrand Russell). On the other hand, when rejecting the Cartesian mentalistic framework, Cassirer argues that thoughts are always bound to their expression in language, and as such have a natural place in the social sphere. According to Kreis, this leads to a notion of nature that leaves room for normativity and representational content, or to Cassirer’s understanding of “objective spirit.”

This chapter focuses on the philosophical analysis of consciousness, on the mind--body problem: how does the physical material of the brain give rise to mind and consciousness? It examines different ways in which mind and body might be related, such as dualism and monism. It discusses problems with both approaches: how do mind and matter interact in dualist theories, and how does hard atomic matter give rise to mental experience in monism? The chapter introduces the concept of the philosophical thought experiment, and gives several important examples, including philosophical zombies, the inverted colour spectrum, and the knowledge argument. The chapter discusses Chalmers’ distinction between the easy and hard problems of consciousness, the ‘hard problem’ being the central one for mind--body research: how do we get consciousness from matter? The chapter discusses different types of physicalism, such as materialism, eliminative materialism and functionalism, concentrating on the idea that mental processing is computation. We conclude with the examination of mysterianism: the idea that humans might not be cognitively equipped to understand our own consciousness.

The resulting picture of mental causation, which is summarized in this chapter, has repercussions for debates about the nature of mind. If virtually all theories about the nature of mind can solve the problems of mental causation, then arguments from mental causation against certain theories become irrelevant in debates between reductive physicalists, non-reductive physicalists, and dualists. Questions about the nature of mind will have to be decided independently of the problems of mental causation.