Freedom in Science and Teaching. - Ernst Haeckel (mobi reader txt) 📗

botany, instruction must be limited to imparting those trifling fragments of knowledge which either consist of mere descriptions of dry facts, or which supply an explanation of them by mathematical formulas. Morphology must be taught as mere descriptive anatomy and systematising, the history of development as mere descriptive ontogenesis. Comparative anatomy and phylogenesis, which by their explanatory hypotheses raise those dead masses of facts to the place of true and living sciences—these must not be taught at all. And how then do matters stand with regard to the cell-theory, that fundamental theory on which every element of our morphology and physiology depends, and by applying which Virchow himself reached his grandest results?

Since Schleiden in Jena, forty years ago, first put forward the cell-theory, and Schwann immediately after applied it to the animal kingdom and so to the whole organic world, this fundamental doctrine has undergone very important modifications, for it is indeed a biological theory, but not a fact. We may recollect under what different aspects its main principles have appeared in the course of these four decades: what changes have taken place in the conception of the cell itself. After the organic cell had originally been conceived of as a vesicle, consisting of a firm capsule and a fluid content, we subsequently discerned it to be composed of a glutinous semi-fluid cell-substance, the protoplasm, and convinced ourselves that this protoplasm and the cell-core or nucleus enclosed in it are the most important and indispensable constituent parts of the cell, while the external firm capsule, the cell-membrane, is not essential and very frequently wanting. But even now opinions widely differ as to how the conception of a cell should be precisely defined, and what consequences must be inferred from the cell-theory, and attempts have not been wanting to upset it altogether and to treat it as worthless. The anatomist Henle, of Göttingen, in particular, has repeatedly made such an attempt, that "gifted" anatomist who, in the preface to his bulky text-book of human anatomy, declared that scientific ideas are mere worthless paper money, and that the noble metal of facts, on the contrary, is the only genuine article. Not long since a bulky volume in quarto appeared, by one Herr Nathusius-Königsborn, in which the cell is explained to be a subordinate plastic element, and the cell-theory is eliminated as superfluous; and this monstrous volume, full of the most amusing nonsense, is dedicated to Herr Henle. Virchow formerly was one of the victorious opponents of the Göttingen physician, and wrote brilliant articles against the "rational pathology" of "irrational Herr Henle;" now apparently he agrees with him that the paper money of ideas is worthless as compared with the noble metal of facts. Of course the cell-theory then loses all its value, and cannot be a subject of instruction; for the cell itself is not a certain and undoubted fact, but only an abstraction, a philosophical idea.

Nothing more clearly shows what a complete change Virchow has undergone in his most important principles, and what an utter metapsychosis in this special province, than his famous axiom, uttered in 1855—"Omnis cellula e cellula." That is unquestionably the boldest generalisation to which the youthful, independent Virchow ever attained, and one on which he justly prided himself not a little. He himself repeatedly compared it with Harvey's saying, which marked an epoch—"Omne vivum ex ovo." But neither of these axioms is universally correct. On the contrary, we now know that every cell does not necessarily originate from a cell, any more than that every organic individual originates from an ovum. In many cases true nucleated cells proceed from un-nucleated cytods, as in the Gregarinæ, Myxomycetæ and others. Nay more, the primordial organic cells could only have originated in the first instance from non-cellular plastides or monads by their homogeneous plasson resolving itself into an internal nucleus and an external protoplasm. Thus, as we subsequently learnt to know most of the exceptions to this generalisation of Virchow, it appeared all the bolder; the more so as we were at that time far from being able to refer all the different tissues of the higher animals with any certainty to cells, and as not a few experiments seemed to point to the hypothesis of free cell-formation. That guiding axiom, which so powerfully furthered the cell-theory, Virchow, from his present standpoint, must wholly condemn as a crime against exact science, and he surely can never forgive himself for having propounded this hypothesis—which was afterwards found to be not universally true—as an important doctrinal axiom.

We shall indeed find much worse sins against his own principles of to-day if we turn to Virchow's own special department of science, namely, pathological anatomy and physiology, the most important division of theoretic medicine. The great and incomparable services which Virchow here effected do not depend on the numerous independent new facts which he discovered, but on the theories and hypotheses by which, like an inspired pioneer, he sought to open a way through the dead waste of pathological knowledge and to form it into a living science. These new theories and the hypotheses on which they were founded, Virchow then propounded to us, his disciples, with such incisive assurance that every one of us was convinced of their truth; and yet later experience has shown that they were in part insufficiently proved and in part wholly false. For example, I will only here recall his famous theory of the connective-tissue, for which I myself in several of my early works (1856 to 1858) broke a lance. His theory seemed to explain a host of the most important physiological and pathological phenomena in the simplest manner, and yet it was afterwards proved to be false. In spite of this, I declare to this day that it was of the greatest service for the development of our acquaintance with the formation of the connective-tissue; as a guiding hypothesis and as a provisional clue to our investigations. Virchow, on the contrary, if he impartially reflects on the part he took in the diffusion of this misleading doctrine, must reproach himself severely for it. For "we must draw a hard and fast line between what we are to teach and what we are to investigate. What we investigate are problems," but "the problem ought not to be the subject of teaching." That Virchow, in his course of instruction, every day belied this, his present view of teaching, that he every hour taught his disciples some unproved theory and problematical hypothesis, every one knows who, like myself, for years and with the deepest interest, enjoyed his distinguished instruction. Still the captivating charm of this instruction—in spite of the defective method of unprepared lectures—lay precisely in this, that Virchow as a teacher constantly let us, his pupils, enter into those problems with which he himself at the moment was occupied; that he propounded to us his personal hypothesis for the elucidation of the given facts. And what really gifted teacher who lives in his science would not do the same? Where is there, or where has there ever been, a great master who in his teaching has confined himself to only imparting certain and undoubtedly ascertained facts? Who has not, on the contrary, found that the charm and value of his instruction lay precisely in propounding the problems which link themselves with those facts, and in teaching the uncertain theories and fluctuating hypotheses which may serve to solve these problems? Or is there for the young and struggling mind anything better, or more conducive to culture, than to exercise the intelligence in problems of investigation?

How unpractical and how absurd is Virchow's demand—that only ascertained facts and no problematic theories shall be admitted in teaching—will be still more strikingly shown by a glance over the remaining provinces of human knowledge. What, indeed, will be left of history, of philology, of political science, of jurisprudence, if we restrict the teaching of them to absolutely-ascertained and established facts. What of "science" will remain to them if the idea which endeavours to discern the causes of the facts is banished? if the problems, the theories, the hypotheses, which seek these causes may not be generally taught? And that philosophy—the science of knowing—by which all the common results of human knowledge are to be bound up into one grand and harmonious whole—that philosophy, I say, must not be generally taught, is, according to Virchow, quite self-evident.

Finally, there remains nothing but theology. Theology alone is the one true science, and its dogmas alone may be taught as certain. Of course! for it proceeds directly from revelation, and only divine revelation can be "quite certain;" it alone can never err. Yes, incredible as it sounds, Virchow, the sceptical opponent of dogma, the leader of the fight for "liberty of science," Virchow now finds the only sure basis for instruction in the dogmas of the Church. After all that has gone before, the following memorable sentence leaves no doubt on this score:—"Every attempt to transform our problems into dogmas, to introduce our conjectures as a basis of instruction, particularly any attempt simply to dispossess the Church and to supplant her dogma by a creed of descent—ay, gentlemen—this attempt must fail, and in its ruin will entail the greatest peril on the position of science in general."

The shouts of triumph of the whole clerical press over Virchow's Munich address is thus rendered perfectly intelligible, for it is well known that "there is more joy in heaven over one sinner that repenteth than over ten just men." When Rudolf Virchow, the "notorious materialist," the "advanced radical," the "great supporter of the atheism of science," is so suddenly converted, when he proclaims loudly and publicly that the dogmas of the Church are the only sure basis of instruction, then the Church militant may well sing "Hosanna in the highest!" Only one thing is to be regretted, that Virchow has not more clearly defined which of the many different church-religions is the only true one, and which of the innumerable and contradictory dogmas are to form the sure basis of instruction. We all know that each Church regards itself as the only truly saving one, and her own dogma as the only true one. But as to whether it is to be Protestantism or Catholicism, the Reformed or the Lutheran confession, whether the Anglican or the Presbyterian dogma, whether the Roman or the Greek Church, the Mosaic or the Mohammedan dispensation, whether Buddhism or Brahmanism, whether, finally, it is to be one of the many fetish-religions of the Indians and Negroes that is to form the permanent and sure basis of instruction, let us hope that Virchow will at the next meeting of German naturalists and physicians divulge his opinion.

At any rate, the "instruction of the future, according to Virchow," will be greatly simplified if he will do this. For the dogma of the Trinity in Unity as a basis of mathematics, the dogma of the resurrection of the body as a basis of medicine, the dogma of infallibility as a basis of psychology, the dogma of the immaculate conception as a basis of genetic science, the dogma of the staying of the sun as a basis of astronomy, the dogma of the creation of the earth, animals, and plants as a basis of geology and phylogenesis—these or any other dogma, at pleasure, from any other church will make all other doctrine quite superfluous. Virchow, "that critical spirit," knows as well as I, and as every other naturalist, that these dogmas are not true, and nevertheless, in his opinion, they are not to be supplanted as the "basis of instruction" by those theories and hypotheses of modern natural science of which Virchow himself says that they may be true, that in a great measure they probably are true, but are not yet "quite certainly proved."

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