a string of propositions that have not one glimmering of meaning without an assumption of principles which as yet have hardly found an entrance into the sober minds of Englishmen. No doubt there are many natural analogies which a laborious experimenter may overlook; and no one can tell, without trial, which of them is, or is not, important. Hence it is not only bad taste, but very bad philosophy, to laugh down a scheme of Nature (such, for example, as the Circular System), merely because it comes not within our preconceived views of a natural arrangement. Every scheme that professes to build on facts, deserves to be severely tested and examined. Again, such are the riches of Nature, that a man, who at first sight seems only to be indulging his imagination, may strike on some new mine of thought that may be of inestimable worth, if he condescend to follow out his views in the honest spirit of an experimentalist. Kepler was a man of this kind. The principle of causality was strong within him; and he had a firm faith in the universal harmonies of Nature. Hence he was led to great discoveries, though, in their specific direction, his first views were guided by a false analogy. At the same time he was a laborious and never-tired observer and experimenter: and the love of law and of material harmonies led him onwards, in good hope, to very great material discoveries. But he did not torture his discoveries to make them bend to his first ideal notions; but he made his ideal notions bend to his discoveries, which he announced in the simple form of material inductive truths. And let no man be led astray by his history, who has not the same temper and the same simple love of truth. If an imagination, like that of Kepler, have led to nature's secrets, because it was tempered by a willing submission to experimental evidence, let us remember, at the same time, that a rash spirit of generalization is one of the marks of ignorance, and that premature theory has too often clogged the progress of physical truth. Of all material sciences, Geology offers perhaps the wildest field for speculation ; yet, in its true history and progress, no science is more practical and inductive. I believe that the premature theories of Werner's school retarded its progress by more than twenty years. A philosophy to be useful should, above all things, be clear in its first principles; but in the work of Oken, principles are set forth as if they were axioms, which are one, almost unmixed, compound of wild, unintelligible extravagance. I have done my best to find some of the principles of sound reason in his fundamental propositions. He tells us, in the first page of his Work, "that Physio-Philosophy has to shew how, and in accordance with what laws, the Material took its origin; and therefore how something derived its origin from nothing.” Woe betide all human philosophy, if such is to be its beginning and its aim! I have read his Work, and I have striven to perceive some glimmerings of steady light among the mists of his first sixty or seventy pages; and nothing have I seen but an ignis fatuus playing, here and there, on a darkness that is palpable and impenetrable. I complain also of the intolerable dogmatism of his Philosophy. Among his most doubtful propositions I find not a syllable of doubt or hesitation. Nor is this all. He is not merely unintelligible, it may sometimes be, from clothing his meaning in words derived from a psychological theory, ill comprehended by his reader; but he is often untrue to Nature in the assertion of material facts, about which any man of common sense may judge, if he but choose to use his senses. Some pages I may not have comprehended, because I am not one of the initiated in the mysteries of transcendental philosophy. But there are points in Oken's volume on which I dare to give a very positive opinion. All his pages on the structure of the Earth give us little more than a compound mass of error, involved in a succession of assertions poured out with the utmost dogmatism, and without one syllable of reserve. Almost everything that he tells us of Geology, and much that he tells us of Mineralogy, must come under this unmitigated censure. His Geology is false to Nature in its beginning, and its middle, and its end*. But it is said that there is a proof of great knowledge in the works of Oken, and many bright original ideas, which may be, and have been, carried out in the illustration of dark and difficult questions of comparative anatomy and physiology. One who aims at everything must needs hit something, and I believe it true that he has done good service; nor would any one grudge him. his honour for all that he has done in the cause of * See Supplement to the Appendix, No. VIII. science; at least, those parts of science which he has studied practically and knows experimentally. His fault is that after experimental studies of the sternest kind, after amassing knowledge, from observation, with no common skill; and after exhibiting in his own person that kind of philosophical inspiration which loves to soar from physical facts to physical theories-from particular to general truths; he then chooses to turn round upon us and to deny the nature of his own material fabric; and to teach us, only through the mists of Idealism, that very knowledge which he had gained as an experimentalist, or learned from the experimental knowledge of other men, and which he never could have gained by any other method. The general truths of physics are, it may be said, the ideal forms of material truths made out by observation and experiment. But what becomes of any general truth if the foundation of experiment be away? It is then but a castle in the air. True physical induction implies a previous series of consistent observations or experiments; and so far must we range ourselves with the Sensualist. But the verbal expression of a law, and the inductive power by which we ascend to the general conception of the law, is an act of a different kind, and brings us to the side of the Idealist but if we choose to remain there, then must there soon be an end of all farther physical progress. Great deductive truths have, no doubt, been brought to light by pure reason from well established laws of nature; but such truths have their limit, and deal only with the conse : quences which follow of necessity from laws already known; but if we wish for a wider grasp of material nature and to rise higher than we have yet done, we must again become the pupils of the empirical school. We must quit our high position, and again condescend to make experiments; which may perhaps only strengthen the position we had already gained; or may give us a better insight into the universal harmonies of nature, and a conception of higher laws than those which could be expressed under the former condition of our knowledge. 11. Digression on some Discoveries of Oken followed out by Owen.-Archetype of Nature--General Scale of Nature. Never existed at one time in the History of the Earth. The reconstruction of the Scale subversive of the Theory of Development, &c. The translation of the Physio-Philosophy of Oken, and the recent publications of Professor Owen, impose on me the necessity of detaining the reader with a short digression on the discoveries of these two great physiologists, so far as they have any bearing on the discussions of this Preface*. All animated nature is formed on a plan, and every new discovery gives but a fuller proof of this great admitted truth. Now in any Division of the animal kingdom is there an archetype, or ideal form, to which all other Other names should be mentioned were I to attempt any thing like a history of these discoveries: but my only wish is, that my sketch may be understood; and I profess not to state facts in their full or historical order. |