The History of Philosophy Read online

  Should science be understood in realist or in instrumentalist terms – that is, are the entities referred to by technical terms in science really existing things, or are they useful constructs that help to organize understanding of the phenomena being studied? Is scientific reasoning deductive or inductive? Is there such a thing as scientific knowledge or, on the understanding that all science is open to refutation by further evidence, should it be understood as a system of powerfully evidenced theories which are nevertheless intrinsically defeasible?

  As regards history: if there is no evidence one way or the other for a claim about something that happened in the past, is the claim nevertheless definitely either true or false, or is it neither? History is written in the present on the basis of evidence – diaries, letters, archaeological remains – that has survived into the present (or so we judge): it is partial and fragmentary, and many of the past’s traces are lost; is there therefore such a thing as knowledge of the past at all, or is there only interpretative reconstruction at best – and perhaps, too often, just surmise?

  Reflection on the kinds of enquiries, and kinds of questions those enquiries prompt, shows that philosophy is the attempt to make sense of things, to achieve understanding and perspective, in relation to those many areas of life and thought where doubt, difficulty, obscurity and ignorance prevail – which is to say: on the frontiers of all our endeavours. I describe the role of philosophy to my students as follows: we humans occupy a patch of light in a great darkness of ignorance. Each of the special disciplines has its station on an arc of the circumference of that patch of light, straining to see outwards into the shadows to descry shapes, and thereby to push the horizon of light a little further outwards. Philosophy patrols the whole circumference, making special efforts on those arcs where there is as yet no special discipline, trying to formulate the right questions to ask in order that there might be a chance of formulating answers.

  This task – asking the right questions – is indeed crucial. Until the sixteenth and seventeenth centuries, philosophers did not often enough ask the right questions in the right way about nature; when they did, the natural sciences were thereby born, developing into magnificent and powerful fields of enquiry which brought the modern world into existence. Philosophy thus gave birth to science in those centuries; in the eighteenth century it gave birth to psychology, in the nineteenth century to sociology and empirical linguistics, in the twentieth century it played important roles in the development of artificial intelligence and cognitive science. Its contributions to aspects of neuroscience and neuropsychology continue.

  But the core of questions in epistemology, metaphysics, ethics, political philosophy, the ‘philosophy of’ pursuits, and the rest, remain; they are perennial and perennially urgent questions, because efforts to answer them are part of the great adventure of humanity’s effort to understand itself and its place in the universe. Some of those questions seem unanswerable – though to act on the thought that they are so is to give up far too soon. Moreover, as Paul Valéry said, Une difficulté est une lumière. Une difficulté insurmontable est un soleil: ‘A difficulty is a light. An insurmountable difficulty is a sun.’ Wonderful saying! for it teaches us that the effort to solve even the seemingly unsolvable teaches us an enormous amount – as the history of philosophy attests.

  What follows, then, is the history of philosophy in today’s meaning of the word ‘philosophy’, showing how the subject matter of today’s philosophical enquiries began and evolved. It is mainly the history of Western philosophy that I describe in these pages, but I give overviews of Indian, Chinese and Arabic–Persian philosophy (and a consideration of philosophy in Africa) to note some connections and differences among the great traditions of thought: see the opening pages of Part V. In all cases I have of necessity focused on the main figures and ideas, and in the case of the non-Western traditions I write as a spectator observing from the other side of a linguistic barrier, having extremely little access to Sanskrit, Pali and ancient Chinese, and none to Arabic.

  A difference between this and other histories of philosophy is that this one does not detour into what most others give, namely, accounts of the theologies of Augustine, some of the Church Fathers of early Christianity and the ‘Schoolmen’ of later medieval times such as Aquinas and Duns Scotus. This is a history of philosophy, not of theology and religion. An oddity of histories of philosophy which include theologians among the philosophers is that there is no better reason to include Christian theologians while excluding Jewish or Islamic ones; and no better reason to include theology in a history of philosophy than to include a history of science (indeed, there is rather more reason to include this latter). A fundamental difference between philosophy and theology is that philosophy is the enterprise of trying to make sense of ourselves and our world in a way which asks what we should think and why, whereas theology is the enterprise of exploring and expounding ideas about a certain kind of thing or things taken to exist actually or possibly, namely, a god or gods – a being or beings supposed to be different in significant and consequential ways from ourselves. As I write in dealing with this point in connection with Arabic–Persian philosophy in Part V, ‘if the starting point for reflection is acceptance of a religious doctrine, then the reflection that follows is theology, or theodicy, or exegesis, or casuistry, or apologetics, or hermeneutics, but it is not philosophy’: and that is the principle of demarcation I apply throughout.

  A way of dramatizing the point more polemically is to say that philosophy is to theology what agriculture is to gardening: it is a very much bigger, broader and more varied enterprise than the particular, localized and focused one of ‘talking or theorizing about a god’ (which is what theo-logos means). Of course in philosophy the question whether supernatural entities or agencies exist, and what difference would follow for our picture of the world and ourselves if one or more did so, from time to time arises; and there are philosophers who, drawing on a conception of deity from ‘natural theology’ (that is, some general considerations about a supernatural mind or agency), use it to guarantee the possibility of knowledge (as Descartes did) or as a basis for existence (as Berkeley and not a few others did). These views are discussed in the appropriate places in the following pages. But the tangled efforts to make sense of something like deity as traditional religions wish to have it understood – omnipotent, eternal, omniscient being or beings, and so forth – is not except tangentially a fruitful part of the story of philosophy, and is left to its own historians therefore.

  Part I

  * * *

  ANCIENT PHILOSOPHY

  Philosophy before Plato

  There is a wall standing between us and the world of antiquity: the period of the decline and fall of the Roman Empire and the rise to dominance of Christianity. Edward Gibbon connected the two phenomena, blaming the former on the latter. He is in significant part right. Remember that in 313 CE the Emperor Constantine gave Christianity legal status and protection by the Edict of Milan, and not long afterwards, in 380 CE, the Emperor Theodosius I decreed by the Edict of Thessalonica that Christianity was to be the official religion of the Empire, outlawing others. The change brought rapid results. From the fourth century of the Common Era (CE, formerly cited as AD) onwards a vast amount of the literature and material culture of antiquity was lost, a great deal of it purposefully destroyed. Christian zealots smashed statues and temples, defaced paintings and burned ‘pagan’ books, in an orgy of effacement of previous culture that lasted for several centuries. It has been estimated that as much as 90 per cent of the literature of antiquity perished in the onslaught. The Christians took the fallen stones of temples to build their churches, and over-wrote the manuscripts of the philosophers and poets with their scripture texts. It is hard to comprehend, still less to forgive, the immense loss of literature, philosophy, history and general culture this represented. Moreover, at the time Christianity existed in a number of mutually hostile and competing versions, and the effort – eventually successful – to achieve a degree of consensus on a ‘right’ version required treating the others as heresies and aberrations requiring suppression, including violent suppression.

  In its assault on the past Christianity had help from others with a similar lack of interest in high classical civilization: Huns, Goths, Visigoths and others – the ‘barbarians’ – whose migrations and invasions into the ever-weakening Roman Empire hastened its collapse.fn1 The shrinking of mental and cultural life was both a cause and an effect of diminishing education; fewer books were written and published, prohibitions were imposed on what could be read and discussed, and the predictable consequences of such circumstances followed in the form of increasing ignorance and narrowness. Christianity congratulates itself on the fact that the preservation of fragments of classical literature which managed to scrape through this period of appalling destruction was the achievement of monks, in later centuries, copying some of the manuscripts that survived; and although this was a merely partial, belated and inadequate response to the wanton zealotry of the earlier faithful, one must be grateful even for that.

  As one would expect, only those texts regarded as most significant and outstanding, by individuals themselves thus regarded, managed to survive – and even so, much of the work of some of the greatest figures perished. Only think: Aristophanes was one of a large number of playwrights in fifth-and fourth-century BCE (‘Before the Common Era’) Athens. From quotations and allusions we know the names of about 170 other comic playwrights and 1,483 titles of their plays. All are lost; just eleven out of more than forty of Aristophanes’ own works survive. We have only seven plays by the tragedian Aeschylus out of seventy whose titles we know. Imagine if, of the thirty-six plays printed in the First Folio of Shakespeare’s works (w
e know of at least one lost play, Cardenio, said to have been co-written with John Fletcher), only four were still extant. If we knew the titles of the other thirty-two, what a mighty speculation they would prompt. Imagine if our remoter descendants had just four of Shakespeare’s plays, no Cervantes or Goethe but only their names and reputations, a fragment or two of Schiller, no Jane Austen or George Eliot but again just admiring mention of them, a few quotations in others’ works from Marx, one leg from Michelangelo’s David, one copy of a copy of a Poussin painting, a single poem by Baudelaire, just a few lines of Keats, and so on – scraps and remnants, and not always from the best of their time; this is how things in fact stand with regard to classical and Hellenic antiquity. (And consider: by the accidents and ravages of history the future might indeed have little more to offer its inhabitants than this.) It is an irony perhaps that it was people associated with another oriental religion – Islam – which, a couple of centuries later, also irrupted into the classical world (or rather, into what was by then the carcass of the classical world), who saved some of that carcass’s legacy from oblivion.fn2

  As these thoughts tell us, what we know of Plato’s predecessors in philosophy – they are conventionally known as ‘Presocratic philosophers’ even though some of them were contemporaries of Socrates – has come to us in shreds and patches. There are two kinds of sources for our knowledge of them: fragments, which are quotations from them in the writings of later commentators, and testimonia, which are reports, paraphrases or summaries given by later writers. The scholarly task of identifying and collating this evidence is known as ‘doxography’. The term ‘doxographer’ is also applied to those individuals in ancient times who preserved scraps of the Presocratics’ writings or views by quoting or reporting them.

  Plato and Aristotle both summarized and quoted Presocratic thinkers – sometimes inaccurately, which well illustrates how careful doxography has to be, given that even these giants could get it wrong. Aristotle is indeed a major source of our knowledge of the Presocratics, because he discussed them often and had three of his students, Eudemus, Meno and Theophrastus, write treatises on various of them. Meno concentrated on their medical writings, while Eudemus wrote about their mathematics and astronomy. Only a few traces of the resulting books survive, as quotations and summaries in the work of yet later writers. Theophrastus discussed the Presocratics’ theories of perception in his On Sensation and their science in his Tenets of Natural Philosophy. A few sections of the first book survive; only the title of the latter remains.

  Aristotle and his students were writing about thinkers some of whom lived two hundred years before their time. The next important source is Cicero, writing two hundred years after Aristotle’s time, in the first century BCE. Thus already the thread was growing longer and thinner – the thread of memory and transmission of sources (manuscript copies following earlier manuscript copies, with mistakes creeping in). Cicero was a serious student of philosophy who sought to inform his Roman contemporaries about Greek thought. But by his time the first age of philosophical genius had passed, and in the centuries that followed other causes of inaccuracy entered the picture, not least polemics – as in the writings of Clement of Alexandria in the second century CE, whose comparisons between Christian thought and Greek philosophy were not designed to favour the latter. Nevertheless he quotes some of the Presocratics, adding to the doxographical store.

  The second century CE in fact offers a fairly rich harvest for doxography. The sceptic philosopher Sextus Empiricus quoted extensively from the Presocratics on knowledge and perception, while Plutarch’s Moralia quotes them on a wider range of topics. An anonymous work of the same period called the Placita (‘Opinions’) does the same. This book was originally thought to be by Plutarch, so for convenience its unknown author is called ‘pseudo-Plutarch’. Later that century Alexander of Aphrodisias quoted a number of Presocratics in his commentary on Aristotle.

  In the early third century CE Bishop Hippolytus of Rome wrote a Refutation of All Heresies arguing that Christian heresies arose from Greek philosophy, in the process quoting extensively from the Greek philosophical tradition in order to refute it, thus paradoxically preserving the views he sought to demolish.

  One of the most useful sources for the history of Greek philosophy is The Lives of the Philosophers by Diogenes Laertius, written in the third century CE. It is an informative and entertaining work, though again not always accurate. It also sometimes, perhaps indeed too often, relies on legend and hearsay, which tempers its value; but nevertheless its value is great. In addition to summaries of biographies and views it gives a bibliography of philosophical works, demonstrating yet again how much has been lost.

  There was an earlier text, of course lost, on which the Placita drew, which later served as a source for the ‘Selections on Natural Philosophy’ of John Stobaeus in the fifth century CE. That earlier text is attributed to Aetius, who lived around 100 CE, and who is thought to have himself used Theophrastus’ book. Another important fifth-century source is Proclus, one of the last heads of the academy Plato had founded nine centuries before. Plato’s Academy (the ‘School of Athens’) was closed by the Emperor Justinian in 529 CE, along with a general ban on the teaching of philosophy because it conflicted with Christianity.

  A very important doxographical source, for all that it dates from a thousand years after the beginning of Presocratic philosophy, is the writings of Simplicius in the sixth century CE. In his commentary on Aristotle’s Physics Book I he quotes a number of the more important Presocratics, in some cases thus serving as the only source of information we have about their views. Significantly, he says that his reason for quoting so extensively from one of them, namely Parmenides, giving more of the text than was necessary for his argument, was that copies of Parmenides’ work were extremely rare and difficult to find, so he felt the need to preserve some of it.

  These are the major sources, but not the only ones. Scattered here and there in other writings are mentions, anecdotes and tidbits which the fine net of doxographic scholarship has trawled up. They come, for some examples, from what remains of the writings of Agathemerus the geographer of the third century BCE, the Chronicles of Apollodorus of Athens, written in the second century BCE, the book On Birthdays by the Roman grammarian Censorinus in the third century CE, and others.

  As already noted, neither the fragments nor – perhaps even more so – the testimonia can be regarded as completely reliable. Apart from their brief and scanty nature, they were quoted or reported by writers with their own agendas in mind, sometimes hostile to the views of the philosopher being quoted or paraphrased. Questions of language, interpretation, context and relationship to other fragments pose difficulties for understanding what was really meant by the fragment or reported view. This caveat has to be borne in mind.

  As a result of the great scholarly achievements of the nineteenth century, when the study of the doxographical sources benefited from advances in philology (the study of language in historical texts), a story of early philosophy emerged which quickly assumed the status of orthodoxy. More recent scholarship, including the discovery of texts like the Strasbourg Papyrus with previously unknown lines by Empedocles, and the Derveni Papyrus containing philosophical quotations among Orphic hymns, complicates the neat picture that the orthodoxy gives, and throws some of it into question.fn3 However in its broad outlines the orthodox story is a good starting guide; the detailed refinements and criticism of recent scholarship make better sense if one knows what it is adjusting.

  That orthodox story goes as follows.