III.
In the series of the fundamental sciences Chemistry appears to fill a somewhat secondary and subordinate place. In it the positive method is not enriched by any process of capital importance, but it confines itself to developing the processes already made use of in physics. In spite of appearances, even experimenting is less easy and less fertile in chemistry than in physics. The only new process which we see appearing is the art of nomenclature. Whenever we wish to study this art “at its source” we shall have to refer to chemistry.[140]
The phenomena which it studies are the most complicated of the inorganic world. If then physics is extremely imperfect, it is not surprising that chemistry should be much more so. In the greater number of its researches “the chemistry of the present day hardly deserves the name of science.”[141] But this inferiority of chemistry is not only due to the nature of its object. There are other causes which it would be easier to remedy. The progress of chemistry is retarded: 1, by the wrong direction given to much of its work up to the present time; 2, by the defective education of the majority of the scientific men who give themselves to its study.
Before all things, chemists lack a clear and rational idea of their science, of its relation to the sciences which stand nearest to it and the way in which its problems should be stated. Being intermediate between physics and biology, chemistry has suffered from the vicinity of both. As the more advanced sciences always have a marked tendency to encroach upon those above them, chemistry must in the first place defend itself against the ascendency of physics, as physics itself must fight against that of mathematics. The chemist must undoubtedly have studied physics, in order to make use of the results obtained by this science, and to turn them, if he can, into a method for his own use. The relation of these two sciences is very close, and a knowledge of the laws of calorific and electric phenomena, for instance, is of the highest importance for chemical research. But, for all this, the chemist has his own point of view. He studies, (which the physicist does not do), the laws of the phenomena of composition and decomposition which are the result of the molecular and specific action of diverse natural or artificial substances upon each other. He must therefore make use of physics, but not subordinate himself to it.
On the other hand physiological research is not within the province of chemistry. What has been called “biological chemistry” belongs, according to Comte, to biology alone. For the physiologist to have gone through the school of chemistry is natural and even indispensable. But his point of view is quite different from that of the chemist. As a matter of fact, chemists have shown themselves unqualified for physiological studies. None of their numerous attempts have succeeded in establishing a single point of general doctrine, in biology. They merely furnished materials. Moreover these cannot be used just as they are by the physiologist, who is obliged to take up the researches again “under the preponderating influence of biological considerations.” Comte admires the self-confidence of the chemists who approach physiological questions without having measured or even suspected the special difficulties. It is, however, clear that the most carefully made chemical analyses must be fruitless here so long as they are not directed in the first place by a precise physiological notion of the whole of the phenomenon, and then modified by the knowledge of the limits of the normal variations to which the phenomena may be liable. Now, for proceeding in this manner, the physiologists alone are competent.[142]
Analogous considerations lead Comte to reject even organic chemistry. Although the chemical phenomena present characteristics which in the inorganic world come nearest to the solidarity which subsists between the elements of living forms, nevertheless chemical phenomena remains irreducible to living phenomena. That which is chemical is not yet organic; and that which is organic is no longer purely chemical. We must do away with this heterogenous and fictitious grouping which is called organic chemistry, to unite the different parts, according to their respective nature, some to chemistry proper, the others to biology.[143]
How can we define the object of this science, so imperfectly determined at the present time? Comte knows that he is about to depart from the methods generally in use among chemists, but he is not afraid of this. For, he says, in order to understand the real nature of a science, we must always suppose it to be perfect.[144] As chemistry, is in an extreme state of imperfection, the “scientific type” which the philosopher conceives respecting it will appear to be very far removed from what exists at present. It matters little so long as this type is perfectly “rational.”
What is essential to science is the possibility of foreseeing phenomena. Given the characteristic properties of the simple or complex substances placed in chemical relations with each other under well defined circumstances, the object of chemistry will therefore be to determine exactly in what their action will consist, and what will be the properties of the new substances produced.[145] According to this definition, the fundamental data of chemistry should be ultimately, reducible to the knowledge of the essential properties of the simple elements alone, which would lead to that of the various immediate chemical substances, and consequently to the most complex and distant combinations. Obviously, the study of simple bodies can only be made by means of experiments, which alone reveal their properties. But, once this basis is laid down, “all the other chemical phenomena, notwithstanding their immense variety, should be capable of rational solutions, according to a small number of invariable laws, established by the science of chemistry for the various classes of combinations.”
Thus, Comte sees clearly that the complexity of the chemical phenomena prevents us from expressing their relations in a form which allows of the use of mathematical analysis. But none the less, in this science as in the preceding ones, he persists in making the experimental method a mere starting-point. The experimental method furnishes the data which it alone can supply. But these data are afterwards elaborated without its intervention. The scientific ideal in chemistry, as in physics and in astronomy, is to substitute as much as possible rational prevision to experimental verification. Science always seeks to deduce the greatest number of consequences from the smallest number of data, and the smallest number of data in this case are the properties of simple bodies. Deduction will establish a priori what the properties of a given combination of two simple bodies, or of two complex bodies will be.
In the name of this scientific ideal, Comte reproaches the chemists with the superabundance of their analytical work. In default of a rational conception of chemistry they do not make their work bear upon the necessary points. What is the use of studying such and such a body, placed in such and such conditions, in an arbitrary way and according to the fancy of investigation? The progress of chemistry should consist far less in the acquisition of new materials than in the systematisation of those which we already possess. Chemistry is to-day as rich in details as it is imperfectly constituted as a science.[146] Its present state in no way gives an idea of what its normal state will be.
Not content with showing to chemists the “scientific type” towards which their science should tend, Comte suggests a contrivance in method which will bring them nearer to it. It is in no way like the hypothesis of affinities, for this appears to him to be even more “ontological” than the hypothesis of imaginary fluids or ethers. As always happens when we are concerned with metaphysical conceptions, the explanations which we draw from affinities consist in the reproduction in abstract terms of the very statement of the phenomenon.[147] To this hypothesis, which is not a scientific one since it bears up the mode of production of facts, Comte substitutes what he calls the “dualist hypothesis.” We ignore, he says, and it is not for us to seek the real manner in which the elements of which bodies are composed come to be grouped together. But, consequently, it is lawful for us, in the very circumscribed sphere of our positive research, to conceive the immediate composition of any substance whatever as merely binary, each of the two bodies so separated being able, according as the case may be, to lend itself to a similar analysis, equally binary, and so on, as the occasion arises. We do not affirm that dualism is a real law of nature. It will be a fundamental contrivance in chemistry, like the hypothesis of inertia in mechanics, and that of atoms in physics. It will serve to “simplify our elementary conceptions” in chemistry, and in having recourse to it we do not exceed “the special kind of liberty” of which our intellect may avail itself, in the institution of science.[148]
The use of this hypothesis would allow us to endow chemistry with a “fine” character of unity and rationality which it lacks to-day. It is true that Comte himself confessed that this hypothesis, proposed by him in 1838, had yet “produced nothing” in 1851. But he explains this sterility to himself by the metaphysical spirit, from which chemists are not sufficiently freed.