II.

Auguste Comte often says that the positive spirit consists in keeping oneself equally distant from two dangers, mysticism and empiricism.[33] By mysticism he understands the recourse to non-verifiable explanations and to transcendent, hypotheses. Men’s imagination finds pleasure in these things, but we must be able to bring all “real” knowledge back to a general or particular fact. Positive science therefore abstains from searching after substances, ends, and even causes. It only bears upon phenomena and their relations.

Empiricism, in its turn, is no less than mysticism contrary to the spirit of science, Empiricism signifies for Comte the knowledge which does not go beyond the pure and simple ascertainment of a fact. Now, an accumulation of even precisely noted facts has no theoretical interest. It may, at most, be erudition, but it is not science. To think that by thus gathering facts together one is labouring at the work of science, is “to take a quarry for an edifice.”[34] In a word, “science is made up of laws, and not of facts.”[35]

Strictly speaking, no scientific observation is even possible without a previous theory, that is to say, without a presupposed law, whose verification is in question. Undoubtedly in science when it has become positive, the imagination no longer constructs “causes” or “essences.” It must submit to reason, that is to say, to the methodical investigation of phenomena. Nevertheless, this investigation cannot take place without guiding hypotheses, and thus the imagination plays a part in science, subordinate it is true, but indispensable. Comte here separates himself from Bacon. According to the English philosopher, in the knowledge of nature, the mind must make itself as receptive as possible. In introducing anything of itself it would falsify science, and its whole effort must be to hold itself up to phenomena as a perfectly plain and unspotted mirror, so as to reflect them as they are. Now this is precisely the idea of science which Comte rejects under the name of empiricism. Without the hypotheses or the theories suggested by the very activity of the mind science would never be constituted, according to him. There would never even be an apprehension of fact, at least an apprehension such that it could be of service to science. In a word “absolute empiricism is impossible.” In the simple observation of a phenomenon by the human mind, the entire mind is interested, and in it the subjective conditions of science are already virtually given.

This being granted, science may be defined as a methodical processus of the connection and extension of our knowledge. It consists, in every department “in the exact relations established between observed facts, so as to deduce from the least possible number of fundamental data, the most extensive series of secondary phenomena, in renouncing absolutely the vain search after causes and essences.” So long as men seek to “explain” phenomena the theological and metaphysical spirit has not yet disappeared. Positive science abstains from all explanations of this kind. Thus, Newton has placed in the same category universal gravitation and the attraction of bodies. We cannot know what this mutual action of the stars and the attraction of terrestrial bodies are in themselves. But we know with full certainty, the existence and the law of these two orders of phenomena and moreover we know that they are identical. For the geometer weight is explained when he conceives it as a particular case of general gravitation. On the contrary it is weight which makes the physicist proper understand celestial gravitation. We can never go beyond such juxtapositions “of ideas.”[36]

But while science brings together similar phenomena, its chief function is to connect them, that is to say to determine them one by another according to the relations which exist between them. All science, says Comte, consists in the co-ordination of facts; and if the several observations remained isolated there would be no science. We may even say generally that science is destined, as far as the various phenomena permit, to dispense with direct observation, in allowing us to deduce the greatest possible number of results from the smallest number of acquired data. If a constant relation is found to subsist between two phenomena, it becomes useless to observe them both; for from the observation of one the variations of the other will be deduced. But the first may in its turn be the function of a third, and so on; until at last we conceive a constant connection between all the phenomena of a given order, which may allow us to deduce them all from a single law. Such for Comte would be the perfect form of science: how near it is to the Cartesian ideal! “The positive spirit,” he says, “without failing to recognize the preponderance of reality directly ascertained, tends to enlarge the rational at the expense of the experimental domain, by substituting the prevision of phenomena to their immediate observation.” Scientific progress consists in diminishing the number of distinct and independent laws, by continually multiplying their respective connections.[37]

“Prevision” thus becomes the essential characteristic of scientific knowledge, and that independently of any utilitarian mental reservation. For the eventual applications of science do not determine its theoretical advance. The prevision with which we are here concerned consists solely in the possibility of knowing with certainty without observing. It is knowledge a priori in the Aristotelian sense of the word, of which mathematics present the most perfect model. A rectilinear triangle being given, I do not need experience to know with certainty that the sum of the angles in it is equal to two right angles. Thus understood prevision applies to the present, and even to the past, as well as to the future. When Comte writes “All science has prevision for its aim,”[38] we must understand: “All science tends to substitute deduction to experience, rational to empirical knowledge.” This prevision, a necessary consequence of the constant relations discovered between phenomena, will allow men never to mistake real science for fruitless erudition, which accumulates facts without deducing them one from another.

Thus the formula cited above enlarges itself: “Science is composed of laws and not of facts.” The more deduction is substituted to experience, the better is the extension and connection of our knowledge realised. Consequently, the more also does science draw near to that unity which is imperatively claimed by our understanding, and which is for it the criterion of truth. “Real science,” says Comte, “regarded from the highest point of view, has no other general object but to establish or to fortify unceasingly the intellectual order, which is the basis of all other order.”[39] The mind which applies itself to the contemplation of the world requires, before everything, to find it intelligible. “Real” science satisfies it, not in imagining wills and causes, as did theology and metaphysics, but in discovering order in the constant relations between phenomena. When this order is harmonious, that is to say, when the several classes of phenomena are conceived as homogenous, and as similarly governed by laws, “the spontaneous unity of our understanding is consolidated.” It matters little that the various orders of phenomena are given to us as irreducible to one another. The highest object of science is to determine the point of view from which all phenomena appear intelligible, and this point of view is one as the understanding itself is one.