The Geometric Spirit
Although the Christian faith had already lost its position as the universally accepted common ground of European thought, it remained central in the sense that every man had to define his relationship to it, had to declare himself a defender, a reconciler, or an opponent. In much the same way, the members of the next generation had to come to terms with materialism, because the critical principles with which their fathers had so vigorously attacked Christianity led unmistakably in that direction. These critical principles rested upon a naturalism which carried through the entire century. Naturalism may be denned as the belief that nature is all-embracing, that nothing exists apart from it, that all man's endeavors—in science, in morality, in religion, in social organization—must rest upon the principles of nature. In these general terms naturalism is compatible with a bewildering variety of philosophies, depending upon the meaning attached to the word 'nature.' By and large, the philosophes derived their image of nature from Newtonian physics, so that for them 'nature' tended to mean the operation of mechanical laws upon material bodies. Therefore their naturalism suggested the doctrines of 'materialism,' the belief that nothing exists except matter, and 'mechanism,' the belief that all causation is mechanical causation and that all activity is subject to the laws of causation. Thus a philosophe could only with difficulty escape the choice between embracing mechanistic materialism, with all its fearsome consequences of nihilism and irrationalism, and repudiating it and risk compromising his hold on scientific naturalism. The challenge of materialism crystallizes the chief dilemma of the Age of Enlightenment. The philosophes were caught between contradictory intellectual commitments: on the one hand, they wanted to integrate man fully into the order of nature, to explain man and all his works in terms of mechanical laws just as they explained the phenomena of physics; on the other hand, as residuary legatees of the Western humanist tradition, they were concerned to preserve man's uniqueness as a rational and moral being. This intellectual dilemma could be viewed with equanimity by a philosopher who kept himself above the battle, but not by a philosophe, because the former could keep his philosophical conclusions separate from his life, while the latter could not. Hume, for example, was a radical skeptic in his study, but he could go about the activities of daily life in full expectation that the laws of causality would hold up. The philosophes, however, were distinguished as a group by their desire to act on their philosophical convictions—to bring philosophy to bear on problems of man and society and to initiate reforms on the basis of reason. An inherent contradiction between thought and action, between philosophy and life, could not therefore be tolerated. If their philosophy seemed to suggest that man is not rational or not free, their whole raison d'etre would be called into question. It was of the utmost importance, then, to seek a way out of the dilemma posed by their thoroughgoing naturalism.
Condillac was dragged into the materialist controversy by his Traite des sensations. Had he not been implicitly accused of materialism, it seems unlikely that he would have either perceived the dilemma or been concerned to resolve it. For Condillac was in many ways an anomaly in his circle. Ever more a philosopher than a philosophe, he lacked the passion and the intellectual daring that characterized the latter group. He was conventional, even timid, in his outlook. Most of all, he had no firm dedication to the reform of society, the regeneration of man, or anything else. Apart from a tepid fidelity to the Catholic faith and a project (one can scarcely call it a mission) to geometrize metaphysics, Condillac was without commitments. His defense of man's uniqueness and spirituality in the Traite des animaux was much more a function of a wish to preserve his orthodoxy than of a passion for Utopia. But before examining the Traite des animaux, it would be well to analyze the pertinent particular problems implicit in the general problem of materialism.
Although it had not been apparent at first, the replacement of the Christian-Aristotelian cosmos by the mechanistic universe of the New Science meant chaos in the moral as well as in the epistemological sphere. The anthropomorphic cosmos of Christian Aristotelianism was a moral and metaphyscial structure, imbued with qualities, purposes, and a built-in hierarchy of values. The philosophes wanted, above all, to avoid metaphysics (in the traditional sense of the term). They wanted to base their social and ethical theories on the scientific study of nature, not on metaphysical speculations about 'essences' and final causes, nor on theological speculations about the supernatural. The hidden assumption, inherited from certain tendencies of seventeenth-century rationalism, was that nature itself constitutes a kind of self-evident metaphysics. The phenomena of nature point beyond themselves to an order or harmony permeating the universe from which judgments of meaning and value can be inferred. The vogue for 'natural' religion and 'natural' theology, basing their claims on 'natural' reason, stems from this assumption. Condillac's generation was beginning to have misgivings about it.
To begin with, there was the question of order. Is there really order in the universe? If so, what kind of order is it? Is it a rational and moral order or merely the order of blind material necessity? How can an impersonal and mechanistic universe have rational and moral purpose? Indeed, even the evidence of natural phenomena, which had at first looked so harmonious, began to appear ominously discordant. Voltaire saw, in the Lisbon earthquake, and Diderot, in his consideration of the world of the blind man, testimony not only to the moral indifference of nature bur also to its lack of order and rationality. There is too much cruelty, too much waste and destruction, too many monstrous and anomalous occurrences, to suppose design in nature. Natural order cannot mean anything but the material necessity of efficient causation. The mid-eighteenth century saw the rediscovery of evil in the universe, but in the context of nature rather than of religion—a difference which proved to be critical. The Christian world-view had taken evil for granted, had accepted it as a consequence of the Fall. Evil had been man's free choice, and he as well as the whole natural order had to suffer from that choice. If there was pain, anguish, and discord in the world, it was because man freely gave the powers of darkness and disharmony a foothold. God allowed it but did not cause it; moreover. God provided redemption at great cost to himself. Sin and evil were no scandal to the orthodox Christian. But one important aspect of the seventeenth-cenrury rebellion against Christian orthodoxy was precisely the rejection of the Christian concept of sin. Deists, for example, wanted to minimize or explain away evil in the universe. They rejected original sin and the torments of hell. They found such concepts degrading to man and unworthy of God, whose universe must be an expression of his own order and harmony. The harmony of the physical workings of the Newtonian universe must be paralleled by a like harmony in its moral workings. But the generation born after 1700, no longer dewy-eyed from the fresh discovery of universal laws, rook a harder look at nature and saw much evil. Lacking a religious explanation for and redemption from that evil, they could only be shocked and disillusioned. The rise of athesim in the middle decades of the century is surely to be explained in large measure by this disillusionment with the serene and happy world of the deists.