The celebrated Cartesian paradox, that animals are unconscious automata, is another consequence of the same principle. In Aristotle’s philosophy, the doctrine of potentiality developing itself into act through a series of ascending manifestations, supplied a link connecting the highest rational with the lowest vegetal life. The identification of Form with pure thought put an end to the conception of any such intermediate gradations. Brutes must either have a mind like ours or none at all. The former alternative was not even taken into consideration; probably, among other reasons, because it was not easily reconcilable with Christianity; so that nothing remained but to deny sensibility where thought was believed not to exist.
Finally, in man himself, thought is not distinguished from feeling; it is, in fact, the essence of mind, just as extension is the essence of body; and all spiritual phenomena are modes of thought in the same sense that all physical phenomena are modes of space. It was, then, rather a happy chance than genuine physiological insight which led Descartes to make brain the organ of feeling no less than of intellection; a view, as Prof. Huxley has observed, much in advance of that held by Bichat a hundred and fifty years later. For whoever deduced all the mental manifestations from a common essence was bound in consistency to locate them in the same bodily organ; what the metaphysician had joined the physiologist could not possibly put asunder.
We are now in a position to understand the full force of Descartes’ Cogito ergo sum. It expresses the substantiality of self-conscious Form, the equal claim of thought with extension to be recognised as an element of the universe. This recognition of self-consciousness as the surest reality was, indeed, far from being new. The Greek Sceptics had never gone to the length of doubting their own personal existence. On the contrary, they professed a sort of subjective idealism. Refusing to go beyond their own consciousness, they found in its undisturbed self-possession the only absolute satisfaction that life could afford. But knowledge and reality had become so intimately associated with something independent of mind, and mind itself with a mere reflection of reality, that the denial of an external world seemed to the vulgar a denial of existence itself. And although Aristotle had found the highest, if not the sole absolute actuality in self-thinking thought, he projected it to such a distance from human personality that its bearing on the sceptical controversy had passed unperceived. Descartes began his demonstration at the point where all the ancient systems had converged, but failed to discover in what direction the conditions of the problem required that they should be prolonged. No mistake can be greater than to regard him as the precursor of German philosophy. The latter originated quite independently of his teaching, though not perhaps of his example, in the combination of a much profounder scepticism with a much wider knowledge of dogmatic metaphysics. His method is the very reverse of true idealism. The Cogito ergo sum is not a taking up of existence into thought, but rather a conversion of thought into one particular type of existence. Now, as we have seen, all other existence was conceived as extension, and however carefully thought might be distinguished from this as absolutely indivisible, it was speedily reduced to the same general pattern of inclusion, limitation, and expansion. Whereas Kant, Fichte, and Hegel afterwards dwelt on the form of thought, Descartes attended only to its content, or to that in which it was contained. In other words, he began by considering not how he thought but what he thought and whence it came—his ideas and their supposed derivation from a higher sphere. Take, for example, his two great methods for proving the existence of God. We have in our minds the idea of a perfect being—at least Descartes professed to have such an idea in his mind,—and we, as imperfect beings, could not have originated it for ourselves. It must, therefore, have been placed there by a perfect being acting on us from without. It is here taken for granted that the mechanical equivalence between material effects and their causes must obtain in a world where spatial relations, and therefore measurement, are presumably unknown. And, secondly, existence, as a perfection, is involved in the idea of a perfect being; therefore such a being can only be conceived as existing. Here there seems to be a confused notion that because the properties of a geometrical figure can be deduced from its definition, therefore the existence of something more than a simple idea can be deduced from the definition of that idea itself. But besides the mathematical influence, there was evidently a Platonic influence at work; and one is reminded of Plato’s argument that the soul cannot die because it participates in the idea of life. Such fallacies were impossible so long as Aristotle’s logic continued to be carefully studied, and they gradually disappeared with its revival. Meanwhile the cat was away, and the mice used their opportunity.
That the absolute disjunction of thought from matter involved the impossibility of their interaction, was a consequence not drawn by Descartes himself, but by his immediate followers. Here also, Greek philosophy played its part in hastening the development of modern ideas. The fall of Aristotle had incidentally the effect of reviving not only the systems which preceded, but also those which followed his. Chief among these were Stoicism and Epicureanism. Differing widely in most other respects, they agreed in teaching that body is acted on by body alone. The Cartesians accepted this principle to the fullest extent so far as human perceptions and volitions were concerned; and to a great extent in dealing with the problems of physical science. But instead of arguing from the laws of mechanical causation to the materiality of mind, they argued from its immateriality to the total absence of communication between consciousness and motion. There was, however, one thinker of that age who went all lengths with the later Greek materialists. This was Thomas Hobbes, the founder of modern ethics, the first Englishman to grasp and develope still further Galileo’s method of mathematical deduction and mechanical analysis.
V.
The author of the Leviathan has sometimes been represented as one who carried the Baconian method into politics, and prepared the way for its more thorough application to psychology by Locke. But this view, which regards the three great leaders of English philosophy in the seventeenth century as successive links in a connected series, is a misapprehension of history, which could only have arisen through leaving out of account the contemporary development of Continental speculation, and through the inveterate habit of looking on the modern distinction between empiricism and transcendentalism as a fundamental antithesis dividing the philosophers of every epoch into two opposing schools. The truth is that, if the three writers just mentioned agree in deriving knowledge solely from experience, they agree in nothing else; and that their unanimity on this one point does not amount to much, will be evident if we consider what each understood by the notion in question.
With Bacon, experience was the negation of mere authority, whether taking the form of natural prejudice, of individual prepossession, of hollow phrases, or of established systems. The question how we come by that knowledge which all agree to be the most certain, is left untouched in his logic; either of the current answers would have suited his system equally well; nor is there any reason for believing that he would have sided with Mill rather than with Kant respecting the origin of mathematical axioms. With Locke, experience meant the analysis of notions and judgments into the simple data of sense and self-consciousness; and the experientialists of the present day are beyond all doubt his disciples; but the parentage of his philosophy, so far as it is simply a denial of innate ideas, must be sought, not in the Novum Organum, nor in any other modern work, but in the old Organon of Aristotle, or in the comments of the Schoolmen who followed Aristotle in protesting against the Platonism of their time, just as Locke protested against the Platonism of Descartes and Malebranche.
The experience of Hobbes differs both in origin and application from either of these. With him, sensible impressions are not a court of appeal against traditional judgments, nor yet are they the ultimate elements into which all ideas may be analysed; they are the channels through which pulsating movements are conveyed into the mind; and these movements, again, represent the action of mechanical forces or the will of a paramount authority. And he holds this doctrine, partly as a logical consequence of his materialism, partly as a safeguard against the theological pretensions which, in his opinion, are a constant threat to social order. The authority of the political sovereign is menaced on the one hand by Papal infallibility, and on the other by rebellious subjects putting forward a claim to supernatural inspiration. To the Pope, Hobbes says: ‘You are violating the law of Nature by professing to derive from God what is really given only by the consent of men, and can only be given by them to their temporal head,—the right to impose a particular religion.‘ To the Puritan, he says: ‘Your inward illumination is a superstitious dream, and you have no right to use it as a pretext for breaking the king’s peace. Religion has really nothing to do with the supernatural; it is only a particular way of inculcating obedience to the natural conditions of social union.’
Again, Hobbes differs wholly from Bacon in the deductive character of his method. His logic is the old syllogistic system reorganised on the model of mathematical analysis. Like all the great thinkers of his time, he was a geometrician and a mechanical physicist, reasoning from general to particular propositions and descending from causes to effects.[554] His famous theory of a social contract is a rational construction, not a historical narrative. But though a mathematician, he shows no traces of Platonic influence. He is, therefore, all the more governed by Atomist and Stoic modes of thought. He treats human nature, single and associated, as Galileo and Descartes had treated motion and space. Like them, too, he finds himself in constant antagonism to Aristotle. The description of man as a social animal is disdainfully rejected, and the political union resolved into an equilibrium of many opposing wills maintained by violent pressure from without. In ethics, no less than in physics, we find attractive forces replaced by mechanical impacts.
While the analysis of Hobbes goes much deeper than Aristotle’s, the grasp of his reconstructive synthesis is wider and stronger in at least an equal proportion. Recognising the good of the whole as the supreme rule of conduct,[555] he gives a new interpretation to the particular virtues, and disposes of the theory which made them a mean between two extremes no less effectually than his contemporaries had disposed of the same theory in its application to the elementary constitution of matter. And just as they were aided in their revolt against Aristotle by the revival of other Greek systems, so also was he. The identification of justice with public interest, though commonly attributed to Epicurus alone, was, like materialism, an idea shared by him with Stoicism, and was probably impressed on modern thought by the weight of their united authority. And when we find the philosopher of Malmesbury making public happiness consist in order and tranquillity, we cannot but think that this was a generalisation from the Stoic and Epicurean conceptions of individual happiness; for it reproduces, under a social form, the same ideal of passionless repose.