A Short History of Modern Philosophy: From Descartes to Wittgenstein, Second Edition (3 page)

We are now in a position to make a preliminary distinction of the greatest importance, the distinction between the history of philosophy and the ‘history of ideas’. An idea may have a complex and interesting history, even when it is obvious to every philosopher that it has no persuasive power. (Consider the idea that there is more than one God.) Likewise an idea may have serious philosophical content, but owe its influence not to its truth but to the desire to believe it. (Consider the idea of redemption.) To be part of the history of philosophy an idea must be of intrinsic philosophical significance, capable of awakening the spirit of enquiry in a contemporary person, and representing itself as something that might be arguable and even true. To be part of the history of ideas an idea need only have an historical influence in human affairs. The history of philosophy must consider an idea in relation to the arguments that support it, and is distracted by too great an attention to its more vulgar manifestations, or to its origins in conceptions that have no philosophical worth. It is surely right for the historian of philosophy to study Kant’s ethics, and to ignore Luther’s
Bondage of the Will,
even though, from the historical point of view, the former would have been impossible had the latter not been written. In conceding such points, we concede also that the best method in philosophical history may be at variance with the practice of the historian of ideas. It may be necessary for the philosopher to lift an idea from the context in which it was conceived, to rephrase it in direct and accessible language, simply in order to estimate its truth. The history of philosophy then becomes a philosophical, and not an historical, discipline.

If the historian of philosophy studies influences, therefore, they will be the influences that derive not from the emotional or practical appeal but from the cogency of ideas. Hence the influence of Hume and Kant will be of the greatest philosophical significance, while the influence of Voltaire and Diderot will be relatively slight. To the historian of ideas, these four thinkers each belong to the single great movement called the ‘Enlightenment’, and in human affairs, where what matters is not cogency but motivating force, their influence is tangled inextricably.

It may happen that an historian of ideas and an historian of philosophy study the same system of thoughts; but it will be with conflicting interests, demanding different intellectual expertise. The historical influence of Rousseau’s
Social Contract
was enormous. To study that influence one requires no better philosophical understanding of the document than belonged to those through whom the influence was most deeply felt—men and women of letters, enlightened sovereigns, popular agitators. The question of its philosophical interest, however, is an independent one, and, in order to approach the document from the philosophical view one must understand and set forth its conclusions with the best intention of determining their truth. To be able to do this one will need capacities of a different kind from those of the people most strongly influenced by the doctrine. One may indeed come to the conclusion (not in this case but certainly in the case of Tom Paine’s
Rights of Man)
that a philosophical work of immense historical importance has no significant place in the history of philosophy.

In what follows the reader must bear in mind this distinction between the history of philosophy and the history of ideas, and recognise that the history that I am outlining is as much created by as it has created the current state of philosophical understanding. My method, however, will be, not to expound the arguments of philosophers in full, but to outline the main conclusions, their philosophical significance, and the kinds of consideration that led their authors to espouse them.

The tradition which has marked out Descartes as the founder of ‘modern’ philosophy should not lead us to erect an impassable barrier between the thought of the seventeenth century and all that had preceded it and made it possible. The method of philosophy changed radically as a result of Descartes’ arguments. But much of its content remained the same. It should not therefore be regarded as surprising if some modern philosophical idea can be shown to have been anticipated by the thinkers of the Middle Ages, in their manifold attempts either to reconcile religion and philosophy or else to divide them.

The spirit of Plato, and that of his pupil and critic Aristotle, have haunted philosophy throughout its history, and it is to them that almost all medieval controversies in the subject can ultimately be traced. They each bequeathed to the world arguments and conceptions of superlative intellectual and dramatic power, and it is not surprising that, wherever they were read, their influence was felt. Each of the important Mediterranean religions—Judaism, Christianity and Islam—attempted either to assimilate their doctrines or to present some alternative that would be equally persuasive and equally compatible with our intuitive sense of the nature of the world and of our place within it.

From Plato and the neo-Platonic tradition the medievals inherited a cosmology which both justified the belief in a supersensible reality, and at the same time presented an elevated picture of our ability to gain access to it. Plato had argued that the truth of the world is not revealed to ordinary sense-perception, but to reason alone; that truths of reason are necessary, eternal and (as we would now say)
a priori;
that through the cultivation of reason man can come to understand himself, God and the world as these things are in themselves, freed from the shadowy overcast of experience. The neo-Platonists developed the cosmology of Plato’s
Timaeus
into a theory of creation, according to which the entire world emanates from the intellectual light of God’s self-contemplation. Reason, being the part of man which participates in the intellectual light, knows things not as they seem but as they are. This theory— initially metaphysical—seemed to imply a corresponding ‘natural philosophy’ (a natural philosophy which had both Platonic and Aristotelian variants). According to this natural philosophy the earth and earthly things reside at the centre of the turning spheres, each representing successive orders of intellection, and each subordinate to the ultimate sphere of immutability, where God resides in the company of the blessed. Reason is the aspiration towards that ultimate sphere, and man’s mortality is the occasion of his ascent towards it. This ascent is conditional upon his turning away from preoccupation with the ephemeral and the sensory towards the contemplation of eternal truth. This ‘natural philosophy’, persuasively expounded by Boethius (c. 480524 AD) in his
Consolation of Philosophy
(one of the most popular works of philosophy ever to have been written), influenced his predecessor St Augustine (354-430 AD)—who nevertheless retained a sceptical stance towards much of Plato’s metaphysics—and reappears in one or another variant, described, upheld and celebrated in countless works of medieval and early Renaissance literature, from popular lyrics to such masterpieces of high art as Chaucer’s
Knight’s Tale,
Dante’s
Divine Comedy
and Spenser’s
Faerie Queene.

The consoling vision of neo-Platonic physics was accompanied, however, by no prescription against metaphysical uncertainty. At every point in the neo-Platonic system problems of seemingly insuperable difficulty were presented to the enquiring mind. What, for example, is this ‘reason’ upon which our knowledge of ultimate truth depends, and what are the laws of its operation? In what sense does it generate eternal, as opposed to transient, insights, and how do we learn to distinguish between the two? What is the nature of God, and how do we know of his existence? What are the laws which govern the movement and generation of sublunary things, and how is the Platonic hypothesis—that man’s residence among them is temporary, and that the end of his being lies elsewhere—compatible with his subjection to those laws? At every point the neo-Platonic cosmology raises problems of a philosophical kind. These problems seem not to be amenable to scientific resolution. On the contrary, they are posed precisely by the suggestion that sensory perception, which is the principal vehicle of scientific thought, leads us not to truth but to systematic (if sometimes persuasive) illusion.

As the theories of Aristotle began to become known among European thinkers—filtered through the writings of Arab philosophers and theologians who had gained them, as it were, by right of conquest— they were avidly studied as the source of new answers to these metaphysical queries. Some of the Aristotelian arguments were familiar to the early Christians. In particular, these arguments had been used in giving philosophical formulation to the doctrine of the Trinity. It was thanks to the philosophers of Alexandria, in particular to Clement (c. 150-215) and Origen (c. 185-254), both of whom had seen the inadequacies inherent in the neo-Platonism of their day, that all the resources of Greek philosophy were used together in the attempt to achieve a coherent statement of Christian dogma. And with the victory over Arianism, and the consequent acceptance of the doctrine of the Trinity, one of the most important of all Aristotelian concepts, the concept of substance, took a central place in the formulation of the credo of the Christian Church. Thus already, by the time that the Council of Nicaea (325) declared the Son to be consubstantial with the Father, a dependence of theology upon Aristotelian metaphysics had arisen. Boethius, in his writing on the Trinity and his surviving translations of Aristotle, did much to reinforce this dependence. But it was only later, at the end of the ‘dark ages’, that the full content of Aristotelian metaphysics began to enter into the philosophical speculations upon which the Christian world-view sought to found itself; and by then the Aristotelian theories had been systematised and adapted by such thinkers as Al-Farabi (875950), Avicenna (890-1037) and Averroes (c. 1125 to c. 1198), all of them Moslems, and Moses Maimonides (1135-1204), a Jew well versed in the philosophical speculations by which the doctrines of the Koran were currently supported. Aristotelian doctrine therefore entered the arena of theology already bearing the stamp of a monotheism which had found it congenial.

The final conversion of Christian theologians to Aristotelian ways of thinking occurred during the eleventh and twelfth centuries, and led, with the founding of universities at such important centres as Paris and Padua, to the rise of that philosophical movement now known as ‘scholasticism’. The greatest luminary of this movement was St Thomas Aquinas (1225-1274), whose
Summa Theologica
purported to give a complete description of the relation between man and God, relying only on philosophical reasoning, and without recourse to mystical assertion or unsupported faith. His master at every point was Aristotle, and the subsequent synthesis of Christian doctrine and Aristotelian metaphysics—known after its creator as Thomism—has remained to this day the most persuasive of the foundations offered for Christian theology.

In order to understand subsequent developments in the history of philosophy it is necessary to grasp some of the conceptions, disputes and theories that emerged from the attempt to set neo-Platonic and Aristotelian doctrine into a framework of monotheistic religion, and in the course of doing so to reconcile classical science and morality with the dogmas of faith. Contrary to the opinion of their successors, the medieval philosophers were not merely slaves of authority, nor were they easily deterred from speculations which led them into conflict with Church or State. As the scholastics themselves were given to saying, ‘authority has a nose of wax’, meaning that if you can get hold of it you can bend it as you will. Nevertheless it is undeniable that, looked at as a whole, their philosophy has a conciliatory aspect, upholding through reason doctrines that either coincide with or leave room for the articles of faith. Consequently, if we are to see what is distinctive in the speculations of this period, we must look behind the doctrines to the logical and metaphysical arguments that were used to support them.

The concept of substance

The Aristotelian logic, expounded in the works known as the
Organon,
was preserved in part by Boethius, and later delivered up in full by the scholars of Islam. Fundamental to this logic is the distinction between subject and predicate. Every proposition, it was thought, must consist at least of these two parts, and, corresponding to these parts, reality itself must divide into substance and attribute, the latter being ‘predicated of’ or ‘inherent in’ the former. The distinction has its origins in logic, and in the Aristotelian attempt to classify all the valid ‘syllogisms’ within a single scheme. But it has clear metaphysical implications. Since substances can change in respect of their attributes, they must endure through change. Moreover, if we can refer to substances it must be possible to separate them, at least in thought, from the attributes with which they might at some particular moment be encumbered. Hence we should distinguish the ‘essence’ of a substance—that without which it could not be the particular thing that it is—from its ‘accidents’, the properties in respect of which it might change without ceasing to exist altogether. Finally, it is substances, in the Aristotelian view, which are the ultimate constituents of reality, and our knowledge of the world consists in our various attempts to classify them into genera and species.

One of the problems that the medievals bequeathed to their seventeenth-century successors was that of whether, and how far, it makes sense to say of a substance that it can cease to exist, or be created. We find that there is an innate tendency in the Aristotelian metaphysic to regard all change as a change in the attributes of a substance. Hence the coming to be or passing away of a substance demands a very special—indeed metaphysical—explanation. For many philosophers influenced by Aristotle, these ‘existence changes’
have
no explanation. Later philosophers such as Leibniz went further, arguing that a substance must contain within itself the explanation of all its predicates. In which case it becomes hard to envisage how one substance might create or destroy another, except by a miracle which, in the nature of things, it lies beyond the capacity of human intellect to understand. A further problem arose from the inability of the traditional logic fully to distinguish individual and species terms from quantitative (or ‘mass’) terms. For example, ‘man’—which can denote both an individual and the class which subsumes him—refers to individual substances. It also expresses a predicate which generally describes them. But what about ‘snow’ or ‘water’? There are not individual ‘snows’ or ‘waters’, except in an attenuated sense which would seem to obliterate a distinction fundamental to scientific thought. This is the distinction between ‘stuff’ and ‘thing’, between what can be measured and what can be counted. The difficulty of forcing the idea of ‘stuff’ into the conceptual frame of ‘substance’ is responsible for much of the rejection of Aristotelian science during the seventeenth century, and for this reason, if for no other, the concept of substance became the focus of philosophical enquiry.