Part 5

The Aristotelian view of Nature as an energetic process failed to impress itself upon his successors. Greek Philosophy soon after Aristotle's death decayed or was deprived of its early vigour, and the doctrine which survived the wreck was essentially derived, however imperfectly, from the Platonic theory.

Throughout the first fifteen hundred years of the Christian era this doctrine undoubtedly dominated the course of speculation--a speculation of which much is now forgotten and almost as much was certainly barren and unfruitful, but of which we would entertain a very mistaken notion if we were to imagine that it was not often pursued with great subtlety and acumen.

One natural result of the fact that such a principle dominated human thought was the prevalence of a belief that the explanation of Nature and natural processes could be derived from the cognitive faculty itself. Our cognition of our immediate surroundings was doubtless continuously corrected by immediate practical tests. But the science of a more extended view of Nature was vitiated by this false principle and in consequence for many centuries our whole Knowledge of Nature remained unprogressive and unfruitful.

Causa aequat effectum, Nature abhors a vacuum, are examples of the maxims derived or supposed to be derived from the necessities of our Reason, and by the aid of which it was vainly hoped to attain a knowledge of Nature and natural laws.

The principle was in itself unsound.

The necessary laws of our rational faculty could discover to us only the essentials of that faculty itself.

The maxims by which it was sought to constitute a priori a scheme of natural laws could not justly claim descent from the necessities of Thought. Had the Schoolmen formed a true conception of the nature of Knowledge they would never have imagined that any necessity of Thought obliged them to believe that a 10 lb. weight would fall to the ground more rapidly than a 1 lb. weight. Equally true is it that their scientific principles had not been derived from any study of the action of natural law. They were unacknowledged intellectual orphans.

The movement associated with the names of Galileo, Bruno, Bacon, Kepler, and Newton owed its origin and its success to the abandonment of this vicious principle. So far as Nature was concerned, the Mind was regarded as a tabula rasa, and the physician set himself to ascertain the laws of nature not by reflection upon his own mental processes or requirements, but by experiment with and observation of natural processes themselves. The result has been the establishment of modern science--the greatest triumph which the human mind has yet achieved.

In a criticism of the writer's essay on The Dynamic Foundation of Knowledge in the Revue neo-scolastique of Louvain, the critic wrote as follows: "Remarquons qu'il n'a pas compris la synthese scolastique du moyen age, elle qui cependant a concilie d'une facon admirable l'actuel et le potentiel dans l'explication de la nature des choses. Il s'est mepris aussi sur les caracteres de la methode scolastique de connaitre la constitution intime du monde experimental; il croit cette methode exclusivement deductive."

We have felt that candour demanded that we should quote the foregoing passage--coming as it does from a source exceptionally well qualified to express an opinion. If we have nevertheless allowed ourselves in the precedent paragraphs of this essay to express again the view which this critic seeks to qualify, but which we still think in the main sound, we are at the same time very glad to be able in this way to invite attention to the undoubted fact that the distinction between the actual and the potential was recognised by the schoolmen as of a very deep significance. We believe further that the real secret of the failure of mediaevalism to extend its Knowledge of Nature was not so much a preference for deductive over inductive methods as the failure to realise that Nature was a dynamic operation.

It is important, then, to understand accurately what is the method of Science.

The external world of our Experience seems to be composed of sensible impressions. The ever present visual panorama combined with the constant occurrence of other sensations suggests that Nature is, as has so often been asserted, simply another name for the sensible presentation. A truer view of Nature was adumbrated by Aristotle when he formulated the theory of an Energy ever generative of the sensible. If the founders of Science did not fully grasp the Aristotelian conception, it is at least certain that they looked upon Nature not merely as a sensible presentation but as a process--a dynamic operation. It was to the study of these operations, to the measurement of the natural forces or normal categories of physical action that Galileo and Newton devoted themselves. The true estimate of a moving force may indeed be said to have been their first great problem, just as the law of universal gravitation was their grandest generalisation.

It was to this sure instinct that the founders of Science owed their success. Had they devoted themselves to the mere study of sensations--of blue things and green things, of hard things and soft things, of loud things and silent things--Science as an efficient and co-ordinated system would never have come into being.

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Having struck the right path, they moved rapidly along it, leaving the Schoolmen and Philosophers behind them, suspicious, hostile, and amazed.

But Philosophy did not remain altogether negative. The new movement extended itself to Metaphysics, and under the leadership of Descartes a resolute effort was made to reform Philosophy on sympathetic lines.

It was in the true spirit of Socrates that Descartes advanced his famous method of Doubt. The whole fabric of beliefs and rational principles was to be subjected to a re-examination, and Descartes found himself on bedrock when he touched his famous Cogito, ergo sum. The simple fact or act of Doubt implied the Activity--the Reality therefore--of the Doubter. But the cogitant subject was reduced very much to the condition of a tabula rasa, and when Descartes proceeded to fill up the blank with a rediscovery on more scientific lines of the essentials of Cognition he found his basal feature in Extension. Tridimensional Space seemed the simple elementary framework of our Knowledge of Nature.

The method of Descartes was further extended by the English philosopher Locke. Those qualities which formed the elements of Knowledge were described by him as the primary qualities of body; the sensible presentation comprised also the secondary qualities which seemed to be in some way superposed upon and contained within the former.

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Our fundamental ideas of Nature were called by Locke sensible ideas. These ideas were derived from our sensible Experience, and it is only just to Locke to point out that, when examined in detail, his sensible ideas are seen to be not mere qualifications of sensation, but rather the elementary characters of Nature viewed as a dynamic process and discovered by our Activity. Yet the ambiguous term sensible ideas unfortunately led to their being regarded as ideas derived, not from our action in any form, but from pure sensation alone.

This extraordinary error was intensified in the speculation of Berkeley and Hume. Experience with them appeared to consist solely of a succession of sensations appearing to, impressing, or affecting a tabula rasa of consciousness.

Of course in such a state of affairs all Knowledge would be impossible. The scepticism which logically followed from such a doctrine was too universal to be capable even of the fiction that it was credible. Berkeley, it is true, endeavoured to save the situation by postulating the incessant and immediate intervention of the Deity as the sustainer of the sensible panorama. This purely arbitrary and fictitious expedient was entirely rejected by Hume, who with fearless honesty carried to its ultimate results the direct consequences of the doctrine and then complacently left human Knowledge to take care of itself.

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A masterly protest against the position of Hume was made by his countryman Reid, who in his Inquiry into the Human Mind very clearly pointed out the fundamental difference between the sensible accompaniments or constituents of our Experience and the real and independently existent substratum by which that Experience is sustained and organised. His argument, though it attracted considerable attention, did not, however, affect as deeply as might have been expected the future of philosophic speculation, probably because he offered no new clue or key whereby to detect the origin and account for the presence in our Experience of those enduring and substantial elements or forms by which it is sustained, but on the contrary left their recognition to what he rather vaguely described as common sense.

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Much more influential was the elaborate answer of Kant, which has profoundly affected the course of Metaphysics since its publication. Reverting in principle to the platonic method, Kant again sought the enduring elements, the fundamentals of Science, in the constitution of the cognitive faculty itself. But very differently from Plato he discovered these in the categories or essential forms of intellective action,--the category of causality and dependence and the so-called forms of the transcendental aesthetic--Time and Space. Under these categories the indefinite data of sensation were thought to be organised into a cognisable system.

A rapid advance of speculation along the lines signalised by Kant took place after his work was published, and for many years this movement was regarded by a large part of the speculative world as the most hopeful and progressive of philosophic efforts, and by its own votaries as placing them in a position of superiority to all other schools of thought. The thoroughness of their studies and introspective methods to some extent justified, or at least excused the arrogance of their pretensions.

But it is to-day almost unnecessary even to criticise this Philosophy.