A Short History of Modern Philosophy: From Descartes to Wittgenstein Page 3
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.
The nature of universals
Any philosophy which asks itself serious questions as to the nature of substances, must also examine the nature of the ‘attributes’ or ‘properties’ that inhere in them. The neo-Platonic cosmology had transformed the original Platonic realm of Ideas—the realm where the ‘forms’ reside, unchanged, unchanging and known to reason alone—into the blessed sphere of immutability. But the old metaphysical dispute between Aristotle and Plato as to the nature of universals remained central to medieval thought. This was because the dispute bore on what is perhaps the single most important issue in the theory of knowledge, the issue of how far the world is knowable to reason. Using as their basic text a passage from Porphyry’s Isagoge, transmitted and commented upon by Boethius, philosophers enquired whether genera and species exist only in the mind or in reality; and, if the latter, whether they exist in individual substances or in separation from them. In answer to this question some philosophers reaffirmed the original Platonic position, upholding the independent existence of universals, in the realm of ‘Ideas’; others went to the opposite extreme, the extreme of nominalism, holding that universals are mere names, and that only individuals exist. There is no independent reality to the idea of ‘blue’: the only fact of the matter here is that we classify things under that label.
One of the most important thinkers to defend a version of the nominalist theory—William of Ockham (floret 1300-1349)—also combined it with a doctrine which seems to be its natural associate. This is the doctrine of empiricism, according to which reason, far from being the sole authority in determining how things are, is subordinate to and dependent upon the senses (upon empirical enquiry). Such empiricism was by no means unusual in medieval thought; it is foreshadowed in Aristotle, and to some extent approved by Aquinas, who lent support to the scholastic tag ‘nihil in intellectus quod nisi prius in sensu’ (‘there is nothing in the understanding that is not first in the senses’), a saying which, under one interpretation at least, implies a thoroughgoing scepticism as to the powers of reason. Ockham was prepared to develop that scepticism to the full, and to combine it, as later empiricists combined it, with a theory of the nature and function of language which would remove the basis from much of the traditional claims made on reason’s behalf. In the course of developing this theory, Ockham was to anticipate many of the major conceptions of later philosophers, including Hume’s theory of causality, Leibniz’s theory of relations, and the attack on absolute space and time. Followed in his scepticism by the vigorous Nicolas d’Autrecourt (c. 1300-after 1350), he provided a powerful challenge to many of the dogmas of the Church, arguing that these must be founded not in reason, which could never stretch so far as to comprehend them, but in faith. In this way, the ancient dispute about the nature of universals served as a focus for the growing disagreement between empiricism and rationalism (as they came to be known). Moreover, it became increasingly apparent, during the course of these disputes, that much in philosophy, perhaps the very possibility of philosophy, depends upon the truth about language. It was consequently in the scholastic age that philosophy began to incorporate the theory of meaning and the study of usage as a central focus of its arguments. Out of this study there emerged important specific theories—such as that of abstract ideas (adopted by Peter Abelard (1079-1142) and bequeathed to Locke and British empiricism) and the doctrine that entities should not be multiplied beyond necessity. This last doctrine, known as Ockham’s razor (though not in fact found in Ockham’s writings), provided the inspiration to much later scientific thought. There also emerged at this time a sense of the centrality of logic to philosophy, and of the need for fine distinctions in the discussion of all philosophical problems.
The ontological argument
Not surprisingly, the rationalist, Platonic tradition of speculative thought lent itself more readily to the support of theological dogma than the empiricist scepticism which took so much inspiration from Aristotle’s attack on Plato’s theory of Ideas. Neverth
eless it was an argument that was Aristotelian both in content and in form which was to have the decisive influence upon medieval theology. This argument is known as the ontological proof (adopting a term of Kant’s) for the existence of God. The discovery of this proof is normally credited to St Anselm, Archbishop of Canterbury (1033-1109), but it is not too great a distortion to find glimpses of it in certain passages of Aristotle’s Metaphysics and in the commentaries of Al-Farabi and Avicenna. It was rejected by Aquinas in his systematic exposition of the basis of Christian doctrine, but nevertheless belongs to a class of arguments others of which he was inclined to accept, and all of which derive their proof for the existence of God by way of the concept of a necessary being—a being whose essence involves existence.
Put very simply, St Anselm’s argument is as follows. By ‘God’ I mean an entity than which no greater can be thought. Suppose that God, so defined, does not exist; I can nevertheless think that he exists. But an entity is greater if it does exist than if it does not. Hence it is possible to think of something greater than God—namely an entity which is not only greater than any that can be thought, but which also exists. But this is contrary to the definition. Hence the hypothesis—that God does not exist—must be false.
If valid, the argument establishes not merely that God exists, but that he exists by necessity, since it follows from his nature (his essence) that he exists. Later versions (such as that endorsed by Descartes) rely on the idea that existence is a perfection and therefore a property of whatever possesses it. It is not clear that St Anselm’s argument relies on this assumption; indeed, to this day it is not clear that the argument makes any questionable assumptions at all. Some philosophers think that it is valid, although only when stated in a refined and novel way; others think it was decisively refuted by Kant, with his attempted proof that ‘existence is not a true predicate’. In any case, despite its sophistical appearance, the argument had a peculiar philosophical tenacity, being accepted in one or another version by all three of the major rationalist thinkers of the seventeenth century.
There is a special reason for the argument’s popularity with medieval theologians, which is that it gives credibility to the idea of God as a ‘necessary being’. Many writers had tried to show that there must be something which exists of necessity (or which is causa sui, cause of itself) if anything is to exist contingently. The ontological argument provides a description of this necessarily existing being, and therefore an answer to the fundamental question of metaphysics, the question why (for what reason) is there anything? Or (to put it more tendentiously) why should Being be? We see here too the origin of that dark dispute, which still appears to live in the obscure pages of existentialist philosophers, as to the relation of existence and essence. If there is no being for whom existence and essence coincide, then what of the remainder? Do contingent objects (among which we must place ourselves) partake of an essence that precedes their existence, or is it the case that, for them, existence must take priority over essence? When we come to discuss this, as yet scarcely intelligible, question, it will be important to bear in mind its relation to those medieval discussions of the nature of God and of universals, which many modern thinkers might unreflectingly suppose to be of merely academic interest.
Free will and human nature
The acceptance of the ontological argument and the resultant conception of a ‘necessary being’, endowed with omnipotence and omniscience, leads almost inevitably to a rigid determinism. If all that is contingent depends ultimately upon the divine nature, and if that nature is governed by necessity, then the world too must follow its course in accordance with the laws which express God’s nature. How then is human freedom possible? This problem arises in slightly different form for those philosophers who adopt the more Platonic conception of the divine nature. Hence it had already been discussed by the Fathers of the Church, and in particular by St Augustine. With the acceptance of the Aristotelian metaphysics it acquired a new dimension, and some of the greatest achievements of modern philosophy result from the continued attempt to describe human freedom, following arguments that had already been surveyed and as often as not abandoned by the scholastics, in their endeavour to fit a plausible account of human nature and human morality into the theological absolutism which reason seemed to demand.
The greatest of these attempts to describe the relation between God and man and to fit the full complexity of human nature into a coherent theology, is undoubtedly the Summa Theologica of St Thomas Aquinas. This work contains what is perhaps the most subtle and complete philosophical account of the nature of human emotion that has ever been produced. As well as incorporating into his work what he considered to be the totality of what was true and well argued in the classical sources available to him, Aquinas attempted to bring to completion the picture of human nature and human virtue presented by Aristotle in his Nicomachean Ethics, and to show its compatibility with the doctrines of revealed religion. While many of Aquinas’s assumptions were soon to be subjected to the scepticism of Ockham and his followers, there is no doubt that he succeeded in convincing his contemporaries that philosophy could not only generate the truth about human nature but also sustain the doctrines of the Christian faith, in such a way as to leave little room for doubt about the major questions of morality and religion which all of us must at some stage in our thinking lives encounter.
Aquinas’s philosophy leaned heavily upon the Aristotelian doctrine of substance and upon the achievements of medieval logic. But, despite its frequent digressions towards empiricism, it was assiduous in the support that it offered to the doctrine of the power and autonomy of human reason. In particular Aquinas did much to revive interest (an interest already exhibited by Abelard) in the Aristotelian theory of ‘practical reason’, as definitive of the active nature of man. The theory of practical reason was held to provide an account of human freedom, together with a description of the ‘good life for man’ that would recommend itself on the basis of reason alone. Aquinas thus handed on to later philosophers a concept without which the study of ethics is either empty or non-existent.
The rejection of scholasticism
The triumph of Thomism was, however, short-lived. Its first serious enemy was the humanism of the early Renaissance. This was accompanied by revolutions in the practice of education which tended to take intellectual authority from ecclesiastics and vest it in the hands of courtiers and literary men; and also by the gradual ascendancy of a spirit of scientific enquiry hostile to the ready reception of theological dogma. During the fourteenth and fifteenth centuries there was therefore increasing criticism of the influence of the schools, and increasing awareness of the lacunae in the systems which they propagated. The intellectual history of this period is complex, and the transition from medieval to modern approaches in education and intellectual life was far less abrupt than our modern taste for clear transitions represents it to be. As late as 1685 William of Ockham’s textbook on logic was standardly used in the University of Oxford, while as early as the Metalogicon of John of Salisbury, Bishop of Chartres (1120-1180), the seeds of Renaissance humanism had been sown, and the medieval theories of education thrown in doubt. Nevertheless, it is clear that between these two periods a change took place in the intellectual climate of Europe that could not but have the profoundest repercussions on the history of philosophy. And two philosophers in particular stand out both as embodying the new spirit of criticism and as laying down the intellectual presuppositions of that style of philosophy which we choose to call modern: Francis Bacon and René Descartes. These two are united by their rejection of traditional authority and their radical search for method. But in the case of Bacon neither motive led him in the direction of those philosophical enquiries which we, with hindsight, see as proper to the modern age, so that, for all his brilliance and learning, it is difficult to see him as the founder of the modern, rather than a destroyer of the medieval, modes of thought. Nevertheless it is fitting to conclude this brief summ
ary with a few remarks about Bacon’s distinctive contribution to modern philosophy.
Sir Francis Bacon (subsequently Viscount St Albans and Lord Chancellor of England) was born in about 1561 and died, dismissed from courtly offices, in 1626. He was a polymath and scholar of the highest order, and even had he never engaged in philosophical or scientific speculation, he would be known through his Essays as one of the great stylists of the English language. But his distinguished place in intellectual history lies in his exploration of the fundamental principles of scientific thought, summarised in the Novum Organum (1620). In this work Bacon sets out to show the inadequacies of Aristotelian science and of the barren a priorism which he associated with the traditional Aristotelian logic of the Organon. He argued that the Aristotelian logic, being purely deductive in character, provides no method for the discovery of new facts, but only a means of arriving at the logical consequences of what is already known. The resulting science must therefore have a purely classificatory character, contenting itself with a division of the known contents of the world into ‘species’ and ‘genera’, without understanding the true causality which leads objects to manifest the similarities whereby we could so classify them in the first place. Instead of Aristotelian science he proposed his method of ‘induction’—the postulation of universal laws on the basis of observed instances—and thereby hoped to promote the ‘true and lawful marriage between the empirical and the rational faculty’. While Bacon’s development of this method was of necessity speculative and incomplete, he did in the course of it make various striking criticisms of the Aristotelian tradition, and at the same time introduce conceptions which were later to prove fundamental to scientific thought. He criticised the theory of ‘final causes’ (the theory that the cause of an event might be found in its purpose), and with it many of the rationalist preconceptions about causation that we shall encounter in later chapters. In place of these ideas he put forward the notion of causality as the generation of one thing from another, in accordance with underlying ‘laws of nature’. He argued that science must always aim at greater and greater universality and abstraction, so ascending ‘the ladder of the intellect’. This could be achieved by a theory whose fundamental laws were expressed not in qualitative but in quantitative terms, since ‘of all natural forms... Quantity is the most abstracted and separable from matter’. It was this conception of science, as the formulation of quantitative laws, that was shortly to gain intellectual ascendancy in the wake of the discoveries of Galileo and Harvey. Bacon also attacked what he saw as the arbitrary and conventional element in the Aristotelian science, and in the course of doing so introduced his doctrine of ‘Forms’, which foreshadowed another, entertained by Locke, that science should treat of the real and not of the nominal essences of things (see p. 90).