Haeckel on the Liberty of Science and of Teaching 1


    II. CHAPTER V. treats of the methods of teaching, and contrasts the genetic method, as advocated by Haeckel, with the dogmatic one recommended by Virchow. The sensation which Virchow's address caused in wider circles was only partly the result of his opposition to the descent theory; its principal cause was his surprising conclusions with regard to the liberty of teaching. Virchow demands that in the school—from the elementary school up to the university—nothing should be taught which is not absolutely certain; only objective but no subjective knowledge is to be communicated to the pupils by the teacher; only facts, no hypotheses. Haeckel remarks that rarely has an eminent representative of science made such an attack upon the liberty of science as did Virchow at Munich. “Where,” he ask, “are we to find the limits between subjective and objective knowledge?” According to his conviction no such limit exists, and all human knowledge as such is subjective. “An objective science consisting only of facts, without subjective theories, cannot be imagined.” He then proceeds to review various sciences in turn, and to point out how much objective knowledge and “facts,” and how much subjective knowledge and “hypotheses” they contain. He begins with Mathematics as the science which is eminently the most certain one of all: “What about the simplest and leepest maxims upon the firm basis of which the whole proud building of mathematics rests? Can they be proved lor certain? Certainly not! The most fundamental maxims are indeed ‘maxims,’ and incapable of ‘proof.’ Only in order to show by an example how even the first mathematical maxims may be attacked by sceptics and shaken by philosophical speculation we recall the recent discussions regarding the three dimensions of space and the possibility of a fourth dimension, discussions which are still continued by a number of the most illustrious mathematicians, physicists, and philosophers. So much is certain that mathematics is absolutely objective as little as any other science, but has a subjective basis in man's own nature. … But even if we own that mathematics is an absolutely certain and objective science, how about all other sciences? No odoubt those are ‘most certain’ amongst the ‘exact’ sciences, the maxims of which are founded on pure mathematics, in the first line therefore a great part of physics. We say a great part, because another great part—upon close examination by far the greater—is incapable of an exact mathematical foundation. Or what we do know with certainty about the essence of matter or the essence of force? What do we know for certain about gravitation, about mass-attraction, about action at a distance, &c.? We look upon Newton's gravitation theory, the basis of mechanics, as the most important and most certain theory of physics, aod yet gravitation itself is only a hypothesis. And then the other branches of physics—electricity and magnetism, for instance. The whole knowledge of these important branches is based upon the hypothesis of ‘electric fluids’ or of imponderable substances, the existence of which is certainly not proved. Or optics? No doubt optics belongs to the most important and most complete branches of physics, yet the vibration theory, which to-day we consider to be its indispensable basis, rests upon a hypothesis which cannot be proved, viz., upon the ‘subjective’ supposition of the light-ether, the existence of which nobody can objectively prove. Nay, even more; before Young established the vibration theory of light, the emanation theory taught by Newton reigned supreme in physics for centuries; this theory has to-day been abandoned as untenable. According to our view the mighty Newton acquired the greatest merit with regard to the development of optics, as he made the first attempt to connect and explain the mass of objective optical facts by a subjective leading hypothesis. But according to Virchow's view Newton sinned most heavily by teaching this false hypothesis; because in ‘exact’ physics only single and certain facts are to be taught and to be ascertained by ‘experiment as the highest means of proof;’ but physics as a whole, resting as it does upon a number of unproved hypotheses, may be the object of research, but must not be taught!” Turning to Chemistry, Haeckel shows that its objectiveness stands upon still weaker feet than that of physics. Here the whole of the science is built upon the hypothesis of the existence of atoms, a hypothesis as unproved and as incapable of proof as any. No chemist has ever seen an atom, and yet he thinks the mechanics of atoms the highest problem of his science, and describes and constructs the positions and groupings of atoms, as if they were before him on his dissecting table. According to Virchow, we therefore ought to banish chemistry from the school and teach only the properties of bodies and their reactions, which can be shown to the pupils as “certain facts.” This matter becomes still more ludicrous when we turn to the other sciences, which are all more or less historical, and therefore do not possess that “half-exact” basis upon which chemistry and physics rest. Geology, for instance, would, according to Virchow, have to confine itself to the description of certain facts, i.e., the structure of rocks, the forms of fossils, the shape of crystals, &c, but would in the school have completely to abandon all speculation regarding the development of the earth's crust, i.e., nothing but unproved hypotheses from beginning to end. We might not even teach that fossils are the actual remains of organisms which existed in former periods, because even this is an “unproved” hypothesis. Even down to the eighteenth century many eminent naturalists believed fossils to be “freaks of nature,” an enigmatic “lusus nature.” In a later part of his address Virchow admits fossils as “objective material proofs;” but even here we may go no further than our actual experience allows, and we may not draw subjective deductions from the objective facts. Virchow's remark about quaternary man being an “accepted fact” affords Haeckei an opportunity for pointing out his inconsistency, and the uncertainty and vagueness of most hypotheses concerning the age and the first geological occurrence of man; indeed, the distinction of a tertiary and a quartery age in itself is nothing but a geological hypothesis. “Virchow tells us that never has a fossil ape skull been found which really belonged to a human proprietor, and that we cannot consider it as a revelation of science, we cannot teach, that man descends from the ape or from any other animal. If that be true, then nothing remains but the descent from a god or from a clod of earth.”

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