One day around the year 430 bc, before dawn, a young and promising Athenian, Hippocrates, son of Apollodorus, hastens to Socrates’ house to rouse him from his sleep. The reason for this bizarre behaviour soon becomes clear: Protagoras is in Athens! With a knowing smile, Socrates answers that he is already aware of this, as though he could not really understand the reason for all this excitement. But Hippocrates shows no hesitation: Protagoras, the great sophist, he who ‘makes people wise’, is in Athens – an opportunity not to be missed! The two of them must leave immediately, and Socrates must help Hippocrates gain access to Callias’ house, where the sophist is staying. However, Socrates insists on enquiring about the reason for Hippocrates’ excitement: does he wish to become a sophist?

In order to understand the meaning and scope of the challenge that the sophists present to us, we must clear the field of all ambiguities and prejudices. All too often the sophist is only taken into consideration as a polemical target, as a counterpart to the philosopher: whereas the philosopher argues in order to seek the truth, the sophist only tries to win an argument; and whereas the philosopher concerns himself with problems in all of their complexity, the sophist instrumentally focuses on fashionable topics that might interest his public of potential pupils (in other words, people willing to pay him). These contrasts are repeated not only in relation to the future, which is to say to Plato and Aristotle, but also, retrospectively, in relation to the so-called ‘Presocratic philosophers’. As a consequence, the sophists find themselves in a sort of no man's land, and their activities appear to mark a break in the history of philosophy, interrupting its toilsome and earnest progression from myth to reason.

An interest in speech and an admiration for those capable of speaking well was a recurrent feature of the Greek world from its most archaic period. Contrary to a certain stereotyped image, the Homeric hero is not celebrated only for his strength and beauty; his ability to express himself is also fundamental: Achilles is the most famous hero, and Phoenix's duty was to teach him how to be ‘both a speaker of words and a doer of deeds’ (Iliad, 9.442–3). In times of war and peace, authority largely depended on one's skill in rhetoric, which allowed one to settle disputes and provide suitable advice (see, for example, Hesiod, Theogony, 83–7). Later on, the development of the institution of the polis further increased the importance of this skill, which became even more crucial in Athenian democracy, in an age in which courtrooms and assemblies shaped men's lives and careers. Hence the sophists’ success, which reflects the fame they enjoyed as masters of the art of speech: it is because he ‘makes you a clever speaker’ that the young Hippocrates wishes to rush off to visit Protagoras in Plato's dialogue of the same name (Protagoras, 312d–e).

The fifth century is the century of nomos, a concept difficult to translate, as it covers several different semantic fields. Usually nomos is rendered as ‘law’, but this is a reductive translation, since the term describes not just positive laws but also traditions, customs, and established practices. Besides, as Aristotle was to observe, the two meanings ‘law’ and ‘tradition’ are closely related: ‘For the law has no power to command obedience except that of habit, which can only be given by time’ (Politics, 1269a20). In short, nomos is anything which is assigned some value, any norm accepted by a group. From the late sixth century onwards, this term acquired a central place in the Greek world, becoming a privileged object of reflection for the sophists. The most significant element is its spread as a technical term for written law, particularly in Athenian democracy. Prior to this, it chiefly referred to customs and traditions. Yet its growing importance is not devoid of problematic aspects. The greater economic and political stability attained through the victorious wars against the Persians led to an increase in travel, cultural exchanges, and trade, which contributed to broadening the perspectives and knowledge of the Greeks. One of the most striking observations they made concerned the wide range of laws and traditions in force in the various cities and states: nomos is indeed a crucial value, as the law and tradition governing the life of a community; but it is in any case relative, as it varies from city to city. The acknowledgement of the relativity of nomos is a central theme in fifth-century literature, as may be inferred from some famous passages by Pindar, Herodotus, and Aeschylus. At first sight, the conclusions reached by these authors would appear to emphasize the capacity of nomos to impose itself: as a verse by Pindar states, nomos ‘is the king of all things’ (fr. 169a Snell-Mähler). Yet the ascertainment of the range of laws and traditions in existence could also lead to moral relativism and to the conclusion that there are no absolute, universal or objective values (Dissoi logoi, 90, 2.18 D.-K. = 40, 2.18 L.-M.).

One frequently overlooked aspect of the sophists’ reflection concerns the kind of problems that today might be included in an ethical treatise, such as happiness and pleasure. Usually it is claimed that the sophists shifted the focus of enquiry from nature to the human world, but then the emphasis is almost exclusively placed on the political side of these investigations (which is no doubt significant, as we have seen in the previous chapter). This is a misleading perspective, which applies modern conceptual schemes to the ancient world, creating distortions and misunderstandings. Before Aristotle, there is no point in distinguishing between the ethical and the political spheres, since ethics and politics ultimately constitute two aspects of the same problem: how to reach fulfilment and thus lead a happy life. Certainly, in order to answer this question it is necessary to embark on an analysis of political problems, such as justice or the best form of government: the fact that human beings live together is something that must be taken into account. But the ultimate goal is self-realization. This is the end towards which everyone tends.

The theme of the gods, of their existence, appearance, and interest in human affairs, was an object of constant attention for the Greeks from the most ancient times. As is widely known, Greek religion presents some highly original features compared with present-day religions: there are no religious texts establishing a body of orthodox doctrines, and no figures to whom worship is officially entrusted. Perhaps precisely because of this fluid situation, the element of the divine marks almost all salient moments in the lives of individuals and cities. This constant presence in itself explains why, from Homer onwards, all writers were so keen to explore the issue of the gods. In particular, many Presocratic philosophers staunchly criticized popular prejudices (often presenting the gods as thieves, adulterers, and seducers) by suggesting alternative and more rigorous conceptions. In doing so, the Presocratics changed the content of the divine, without denying its existence: they opposed the theology of the philosophers to the theology of the poets. The sophists also fit within this broader movement towards the critical redefinition of traditional religiosity, a movement which engaged many leading personalities of the age: let us think of Euripides, of Thucydides’ analysis of the plague, or of the debate on the ‘sacred disease’ (epilepsy) among Hippocratic doctors. In particular, the sophists stand out on account of what we might term their ‘sociological’ perspective: while criticizing the phenomenon of religion, they acknowledged its importance in human life; searching for its causes, they embarked on enquiries into the nature of the gods, the origin of the belief in their existence, their role in people's lives, and myths as a means to convey traditional values.

As already noted in Chapter 1, it is difficult to pinpoint the number and identity of all the sophists who in the fifth century bc travelled from city to city educating Greece, as Hegel put it, or corrupting it, as Aristophanes believed. In what follows, an attempt will be made to provide an exhaustive overview of the most authoritative sophists, without overlooking those minor, or not so well-documented, figures who present some interesting features.

As we have repeatedly verified, competition with other ‘intellectuals’ was crucial for the sophists: while poets and philosophers were their primary targets, they engaged in an equally staunch polemic against the representatives of other forms of knowledge (the so-called technai), such as medicine, music, agriculture, and mathematics. The sophists affirmed the superiority of their teaching against such people as well. As far as we can tell, this claim was advanced in two different ways. In the case of Hippias (a famous polymath), and probably of Prodicus and Antiphon too, the sophists claimed to be as competent as specialists in a wide range of subjects: this explains the interest of sophists such as Hippias and Antiphon in geometrical problems (86B21 = 36D36L.-M.; 87B13 D.-K. = 37D 36a–b and R14–16 L.-M.), and Prodicus’ focus on agriculture.