The world of the Christian fathers from Ambrose to Isidore of Seville had come to differ profoundly from the world of the early Apologists, of Origen and Tertullian. The transformations which produced these differences came in two great waves: the first, sweeping across the whole of the Roman world, is the crisis of the third century from which Roman society was to emerge into a new stability in the fourth, a stability won through extensive re-organisation and accompanied by far-reaching changes not only in the administrative and social structure of the Empire, but also in its traditional culture and religion. These changes, though their incidence differed from region to region, affected the Empire everywhere. The second wave rolled mainly over the Western provinces: the Germanic invaders who settled within imperial frontiers came to create their own, eventually independent, kingdoms on what had been Roman soil. Both waves radically altered the social and political structures of Western Europe, and also the cultural conditions in which reflection on those structures could take place.

The later Roman Empire

The reforms of the emperors at the end of the third century, continued by Constantine in the fourth, secured the Empire from anarchy, from military, economic and social collapse. The means employed, emergency measures which gradually turned into a system, created a novel kind of political reality: a centralised, bureaucratic state very different from the Empire as it had been in the time of the Antonine or even the Severan dynasty.

The conciliar movement of the late fourteenth and early fifteenth centuries was an attempt to modify and limit papal control over the Church by means of general councils. It was sparked off by the disputed papal election of 1378, when, following the return of the papacy from Avignon to Rome, French cardinals rejected the election of the Italian Urban VI, on canonical grounds, and elected Clement VII as anti-pope. The movement was also a response to growng centralisation of church administration and justice, to perceived abuses of power by the (in fact rather weak) papacy in exile at Avignon (1305–77) and to the widespread desire for church reform. There was, further, a latent contradiction in church tradition between the doctrinal authority of councils and the jurisdictional primacy of Rome. The movement was led mostly by Frenchmen and Germans; it evoked little response in Italy. Conciliarism was a moderate programme in comparison with the aspirations of men like Marsilius, Wyclif or Hus, who wanted national or state churches, and who saw whole aspects of Catholic tradition, especially papal authority, as fundamentally opposed to scripture or to reason. But it also reflected a shift in religious sentiment from universality to nationality, and a sense that religious matters could legitimately be debated, at least by all educated clergy. In the event, the pope–council conflict affected considerably the structure of medieval Christendom. What emerged as the practical alternative to papal centralisation was devolution of power to secular rulers and nation-states.

Philosophers: metaphysics, ethics and political theory

European political philosophy had its first home in Greece, in a society made up of numerous small city-states, each with its own laws, customs and constitution. The term ‘politics’ in fact derives from ‘polis’ the Greek noun for ‘city-state’. The sheer variety of constitutions known in Greece – Aristotle and his school were to produce monographs on no less than 158 of them – meant that it was hardly possible there, as it may well have been in Egypt or Mesopotamia, to assume that there is only one way in which to run a society. Varied as the Greek states were, and subject to further variation by reform or revolution, they fell into three main classes – monarchy or rule by one man, described approvingly as ‘kingship’ or disapprovingly as ‘tyranny’; oligarchy or rule by a few, politely called ‘aristocracy’ or rule by the best; and democracy or rule by the entire adult male citizen body, known to later detractors as ‘ochlocracy’ or mob-rule. Their respective merits were hotly discussed from the time of Herodotus (3.80–2) onwards, even if some states, notably Sparta, a totalitarian society much admired for its discipline, stability and prowess in war, fell into none of these categories.

Different societies, it was observed, tend to produce different kinds of people. Democratically ruled Athenians, for instance, had a different character from oligarchically ruled Corinthians. Such observations, abundantly reinforced by a growing familiarity with the customs of foreign peoples, brought home the importance of social factors, of ‘nomos’, a term which meant not only ‘law’ but ‘convention’.

The problem of the Christian Empire: ‘Imperium’ and ‘Sacerdotium’

Two traditions shaped the political thought of Western Christendom in the later fourth and the early fifth centuries, the age of St Ambrose and St Augustine. The first was the collection of ideas about human society which the Christian fathers of the fourth century inherited from the pre-Constantinian period. This included, of course, the hints on these subjects contained in the New Testament writings as well as ideas elaborated by Christians of the second and third centuries, in large part but not entirely in their reflection on the New Testament hints and their implications (see part I, chapter 1 above). The second set of ideas consisted of those engendered by the Christian response to the conversion of Constantine and to the progressive christianisation of the Roman Empire culminating, during the years which spanned the careers of Ambrose of Milan and Augustine of Hippo, in the official establishment of Christianity as the legally enforced religion of the Empire. Christians have always been apt to see the conversion of Constantine as a watershed between the age of a persecuted church and the age of a triumphant established Christianity. Whatever the appropriateness of such a view may be to the historical development (see Introduction to part III, above pp. 86–7), it does only partial justice to the political ideas rooted in the two different sets of circumstances, and to their overlap in the post-Constantine age.

Sources

In order to discuss medieval theories of government one must first locate them. There are very few medieval works whose avowed aim was the examination in conceptual terms of current governmental problems. Therefore the bulk of material has to be extracted from works that had another purpose. But this at once creates uncomfortable choices. The sources conventionally used by historians of political philosophy differ both from those on which constitutional historians habitually draw and from those appropriate for the investigation of medieval man's unspoken assumptions about government. Yet all three have some claim to reveal the ‘real’ political thought of the age. And past studies suggest that they do not blend easily.

Because it would be folly, in the space available, to attempt a complete approach to the subject, this discussion will be limited both geographically and conceptually to the examination of certain academic and official texts on government produced in England and France between 1150 and 1450. Concentration on England and France is justified by their strong cultural and political ties throughout the later middle ages, and by a large stock of common experience. Although by the end of the period their political systems were often contrasted, they nevertheless remained more like each other than either was like the Empire, Italy or Spain. The emergence of powerful vernacular traditions, the loosening of the link between Paris and Oxford universities, the growing sense of national identity, could not totally erase the past they had shared.

The Parmenidean challenge

Nature, for Aristotle, is an inner principle of change. If we are fully to understand what it is for man to have a nature, we must understand Aristotle's conception of change. This is no trivial matter. For in the intellectual climate in which Aristotle grew up it was not obvious that change was possible at all. As Aristotle said,

The reference is obviously to the pre-Socratic Parmenides, and his followers, who argued that change was impossible. For a change to occur, Parmenides argued, something would have to come into existence from a state of non-existence. But from nothing nothing could come to be. But nor can something come to be from something, for something already exists and thus cannot come to be.

Aristotle's Metaphysics begins:

Aristotle is attributing to us a desire, a force, which urges us on toward knowledge. Of course, for some this desire does not exercise great influence; but for some of us it plays an important role in our lives. Aristotle no doubt believed it was this desire that motivated him to do the research and thinking that led to his writing the Metaphysics, and he trusted in this desire to lead others to study it. It is this desire that is responsible for your reading and my writing this book.

How did Aristotle know that we have this desire? One does not know the content of a desire unless one knows what ultimately satisfies it. By its satisfaction we learn what the desire is a desire for. That is why Aristotle speaks of the delight we take in our senses. If the knowledge we pursued were merely a means to a further end, say, power over others or control of the environment, then our innate desire would not be a desire for knowledge.

Man is not only a political animal. He also has within his breast the desire to understand. And there is a serious question as to how man can both fulfill his nature as a political animal and fully satisfy his innate desire to understand. The conflict is one which takes time to develop. For to a certain extent the desire to understand helps man to live the life of an active citizen. For man comes to understand that the ethical life within society is a way to achieve genuine human happiness; and when man comes to understand what happiness is, he is more likely to achieve it. However, if man pursues his desire to understand to the full he will find himself drawn outside the ethical life. It seems that it is man's nature to transcend his nature. Man is by nature a political animal, but he is also an animal who by nature desires to understand the world. And in coming to understand the world, he will leave the ethical life behind. His nature will take him beyond (or outside) his natural life as a political animal.

How are we to understand such a paradoxical conception? One way is to investigate the structure of theoretical understanding. For if we grasp what the desire to understand is a desire for, we may be able to see how satisfying the desire – achieving theoretical understanding – takes one outside the ethical life in society.

Nature as an inner principle of change

If we are to understand what it is for man by nature to desire to understand, we must understand what it is for something to exist by nature (phusei). Aristotle begins Physics II by saying that existent things can be divided into those which exist by nature and those which exist from other causes. The Greek word which is translated as ‘cause’ does not mean cause in the modern sense: namely, an antecedent event sufficient to produce an effect. Rather, it means the basis or ground of something. Aristotle later says that we do not understand something until we know why it is what it is: and the cause gives us ‘the why.’ We shall discuss Aristotle's conception of cause later. For the moment, the important point is that Aristotle thinks that to say that something exists by nature is to cite its cause.

Aristotle thinks he can unproblematically identify the things that exist by nature. The paradigms are living organisms – animals and plants – but he also includes their parts and the ‘simple bodies’ – earth, air, fire, and water. The task, for Aristotle, is to find the characteristic feature which distinguishes natural items from everything else. ‘Each of them,’ he says, ‘has within itself a principle of change and rest.’ The ability to grow is obvious in plants and animals, and animals can move about their environment, but even the simple elements have tendencies to move in fixed directions.

Soul

Soul was traditionally thought to be a principle of living things. Soul was invoked above all, Aristotle says, to explain two remarkable features of animal life: the capacity for movement, and the capacity for cognition – perception and thinking. However, previous thinkers treated soul as an independent item, which they joined to a body without explaining how the two could be related. Aristotle thinks he can give an adequate account of soul and its relation to body by relying on his distinction between form and matter. He defines soul as ‘the form of a natural body having life potentially within it.’ Since the form of a living body is its nature, it turns out that soul is the nature of living things: the inner principle of change and rest.

Form is the actuality of a body, the matter a potentiality, so soul is the actuality of a living organism. However, Aristotle distinguishes different grades of actuality. Aristotle uses the distinction between having learned an organized body of knowledge (an epistēmē) and actually exercising that knowledge. It is fitting to think of one's knowledge as an actuality: for one has passed beyond the stage of merely being capable of learning, one has actually acquired the knowledge. There is nothing that is left which remains to be done in order to be able to exercise it at will. Nevertheless, this does not seem to be as high a level of actuality as the exercise of one's knowledge.

The point of the Nicomachean Ethics

One reason for going back to Aristotle's ethics is to study how profoundly different his ethical outlook is from our own. It is fair to say that we live today without a coherent and compelling morality. There are various moral strands which pull in various directions, but when pushed for a justification we find it hard to explain why we should hold the moral beliefs we do hold. Much of what constitutes the Western moral outlook is inherited from the Judaeo-Christian tradition, and if 300 years ago one were asked, for example, why you should do unto others as you would have them do unto you, one would have undoubtedly given a religious answer. In the past 300 years there has been a dramatic loss of confidence in the ability of religious belief to ground a moral outlook. In part this loss is due to a growing conviction that moral beliefs ought to be justifiable other than by appeal to divine authority: they ought to appear reasonable to a moral agent. But with the loss of confidence in religion's ability to ground morality, no other form of justification has come to take religion's place. There are other forms of justification, to be sure, but none commands universal or deep respect.

One way in which we differ from the Greek world in which Aristotle lived is that we place more emphasis on intention than on act.

I wrote this book as a way of saying goodbye. I first went to Cambridge on a Mellon Fellowship when I graduated from Yale in 1970, and with occasional excursions back to the United States I ended up staying there for almost twelve of the next fifteen years. Cambridge is in many ways my intellectual and emotional home: I had never seen before such a warm, supportive, yet challenging intellectual environment. Perhaps that is why I stayed so long. When I decided to return to the U.S. in 1985, I wanted somehow to mark, intellectually if not emotionally, the time I had spent in Cambridge. Most of my research on Aristotle was done while I was first a student and later a Fellow at Clare College, so I decided to write an introduction to his philosophy. I liked the idea of an introduction, first, because I thought it would force me to work on a broad canvas: to elucidate the thoughts of years rather than detail a single argument. Second, I wanted to write a book that was accessible to my friends who are not Aristotelian scholars – friends who would ask me in countless casual conversations, ‘What do you think Aristotle would have thought about this?’ I am not going to mention my many Cambridge friends by name: if you are one of them and are reading this, suffice it to say that you are very much in my heart and mind.