The Philosophy of Auguste Comte

by Lucien Lévy-Bruhl

The character of generality which, with that of abstraction, is made use of to institute the hierarchy of phenomena is thus reduced to the idea of dependence. It is the consideration of this dependence which assigns to astronomy its place between mathematics and physics in the encyclopædic ladder of the sciences. Considered singly in themselves, the phenomena studied by astronomy are purely geometrical and mechanical. They would not, therefore, constitute the object of a science distinct from mathematics. But positive philosophy considers everything from the point of view of humanity. Now, for humanity, this “special case” is of unequalled importance. All the other phenomena given to us by experience (except the mathematical phenomena) depend, in a more or less direct manner, upon astronomical phenomena. The knowledge of astronomical laws is therefore the necessary condition for the knowledge of all the others. Thus, the infringement of the principle of the hierarchy of fundamental sciences is only apparent. An analogous case is found in chemistry. The analysis of air and water is incorporated in abstract chemistry, because air and water constitutes the general milieu, “in which all ulterior phenomena occur.”[118]

The place given to astronomy is therefore justified. This science, moreover, remains abstract. For it to be a concrete science, all aspects of the existence of celestial bodies would have to be studied and considered in their relations, to each other in it. But, on the contrary, astronomy only studies the geometrical and mechanical phenomena in the celestial bodies, all physical and chemical considerations, etc., being eliminated. Comte concludes that in passing on to the celestial case mathematics does not lose its abstract nature. It only becomes more developed in the case of a special example, whose extreme importance demands such a specialisation.

The abstract character of astronomy belongs to it almost a priori. The facts upon which it rests are only revealed to us by one of our senses, the most intellectual of them indeed, but by which we are only informed of the mathematical properties of bodies. Our eyes alone touch the stars. There is no astronomy for a blind race. Dark stars, if such there be, are for ever hidden from us. All that is given to us, therefore, is the shape, the position and the motion of visible celestial bodies. We can never by any means know how to study their chemical composition, nor their mineral structure, nor a fortiori the nature of the organic bodies which may live upon them. Comte might have formulated in less categorical terms affirmations which were soon to be contradicted by spectral analysis and by photography. But he was confirmed in the entirely abstract and mathematical conception which he had of astronomy by his persuasion that no discoveries of so far-reaching a nature were possible.

Thus, astronomy appeared to be an excellent type of a positive science, because it is at once natural and abstract, and in it these two characteristics are equally apparent, which was not the case in mathematics. In this science the share of observation is so limited, so transient, that it becomes inappreciable. In astronomy, on the contrary, determination of certain facts evidently plays a part in the science. But, at the same time, nowhere do we see more clearly that science does not consist in the mere apprehension of facts. Here they are so simple, and moreover so uninteresting, that their connexion and the knowledge of their laws alone deserves the name of science. In general, what is an astronomical fact? None other than this: such a star has been seen at such a precise instant, and under such an angle duly measured. The more or less profound elaboration of these observations is indispensable to science, even in its most imperfect state. Astronomy, says Comte, did not really come into being when the priests of Egypt or Chaldea made a series of more or less exact empirical observations in the heavens; but only when the first Greek philosophers began to reduce the general phenomenon of diurnal motion to a few geometrical laws.[119]

Of all the natural sciences, after mathematics, astronomy is also the most perfectly free from all theological and metaphysical considerations. From every point of view it is positive. Astronomers no longer have recourse to a Providence, which as the intelligent cause of the order of the celestial world, would in its turn, witness to the existence of this cause. They do not inquire any more into the intimate nature of forces (gravitation, attraction, etc.). Astronomy is content to determine the invariable relations of phenomena with the greatest possible precision. It is here that philosophical minds can study the essential characteristics of a positive science. In it they will also see how disinterested it must be in order to become useful. “Without the highest speculations of geometers upon celestial mechanics, which have so greatly increased the precision of astronomical tables, it would be impossible to determine the longitude of a ship with the degree of accuracy which is now attainable.”[120]

Finally no science has exercised a greater influence upon the evolution of the human mind than this one. The great epochs in astronomy are also those in cosmological philosophy. The desperate resistance which was offered by theological dogmatism to Galileo’s discovery responded to a just apprehension of the consequences involved in this discovery. To admit that the earth was not the centre of the world was to take a first and a decisive step in the way which leads away from the anthropocentric prejudice. It was like pledging oneself to substitute sooner or later the relative point of view to the absolute one in philosophy. It was introducing the positive spirit, to-day in speculative physics, to-morrow in speculative ethics.

II.

Although astronomy is an “eminently mathematical” science, the method of working by observation is used in it. The astronomer observes before calculating, and he observes again after having calculated. The art of observation for which there is no use in mathematics appears here then, and, with it, the inductive method.

Indeed there is no “absolute separation” between observing and reasoning.[121] The mind does not first observe facts in a receptive or “passive” manner, in order to work out combinations of these facts afterwards. In reality every observation is a combination, and this is particularly true in astronomical observation. The facts which we observe are really constructed. We can only see simultaneous or successive directions, according to which the mind must construct the form or the movement which the eye could not take in. The necessary and constant association “between prevision and inspection” is more intimate and more evident here than in any other science.

In the same way, hypothesis (which is inseparable from observation) can be studied in astronomy in its most simple form. Here it is presented in its clearest aspect, and, if one may say so, in the one which most reveals its essential nature. Now, hypothesis in astronomy “serves to fill up the necessary gaps in observation.” It provisionally supplements the knowledge—not indeed of causes, for positive science seeks nothing of this kind—but of facts and laws which we ignore. For instance, the simple geometrical sketch of a diurnal motion would remain impossible without an abstract hypothesis which being compared with the concrete spectacle presented by the movement itself enables us to connect together the various celestial positions. Modern astronomy, which has destroyed primitive assumptions regarded as real laws of the world, has maintained their permanent value for conveniently representing phenomena provisionally. And, as we are not deceived as to the reality of such assumptions we can use without scruple any one which seems to us most advantageous.[122]