Sept. 28, 1882] 



NATURE 



537 



dati m-stone of knowledge, and endeavoured to discover a natural 

 original basis of all things. This conscious aspiration 

 .Hue causality, after ihe unifying knowledge of a 

 common cosmic cause, appears all the more admirable that proper 

 experimental investigation of nature was at that time quite out of 

 the question. 



Perhaps the most important among these Ionian natural philo- 

 sophers was Anaximander. He assumes that out of infinity of 

 matter through eternal revolution numerous world-bodies came 

 bit ) being as condensations of the air, and that the earth, 

 too, as one of these world-bodies, issued out of a state origi- 

 nally fluid and afterwards aeriform. He consequently anticipated 

 the fundamental conception, valii at this day, of the natural 

 development of the world, which 2400 year-, subsequently, in 1755, 

 our greate.-t German philosopher, Immanuel Kant, in his "Uni- 

 ver-al History of Nature and Theory of the Heavens," universally 

 !. Ashere in thee ismological kingd im, Anaximander 

 appears as forerunner of Kant ami 1 .aplace, 50 also at the same time 

 iu tlie biological Kingdom he prophetically prefigures Lamarck 

 and Darwin. For according to him the earliest living creatures 

 on this globe originated in water through the operation of 

 the sun. From these creatures, later on, were developed the 

 land-inhabiting plants and animals which left the water and 

 adapted themselves to life on dry land. Man, likewise, has 

 gradually worked himself up from animal organisms, and, in 

 reality, from fish-like aquatic animals. 



If here to our surprise we find clearly enunciated some of the 

 most important fundamental conceptions of our current theory of 

 development, we recognise it stili more distinctly in its integrity 

 one hundred years later in Heraclites of Ephe-us. He it was 

 wh first propounded the principle that a great uninterrupted 

 process of development prevades the whole universal world, 

 that all forms are involved in an everlasting current, and that 

 struggle is "the father of all things." Seeing that nowhere in 

 the world exists absolute rest, and that all standing — still is but 

 apparent, we are compelled everywhere to assume a perpetual 

 change of matter, a constant variation of f irm. That is only 

 po.-sible, however, through the fact that one form thrusts out the 

 other, and that the new violently usurps the place of the old ; or, 

 in Oiher words, through the universal "snuggle for existence." 



This principle of nature set forth by Heraclites that everlasting 

 movement or the struggle among all things is the fundamental 

 agent of the world received a much deeper interpretation a little 

 later in Empedocles of Agrigent in Sicily. He, too, assumes an 

 uninterrupted change of phenomena, but finds the universal 

 fundamental cause of the everlasting universal struggle in the 

 two counteracting princ pies of hate and love, or, as our modern 

 physics expresses it, of the attraction and repulsion of parts. 

 As the mixture of bodies is effected by love so i~ their separation 

 by hate. If in the present day we regard the attraction and 

 repulsion of atoms as the ultimate ground of all phe aomena we 

 find, then, this fundamental proposition of our modern doctrine of 

 atoms already anticipated in Empedocles. It is however still 

 more remarkable that Empedocles makes the purposive forms 

 of organisms come into existence through the accidental con- 

 junction of counteracting forces. Out of this great struggle the 

 living forms now existing have issued victoriously because 

 they were best prepared for the battle, and therefore most 

 capable of life. Here we have not only the fundamental con- 

 ception of Darwin's theory of selecti m forestalled, but also the 

 solution of the great riddle indicated, " How can organic forms 

 constituted for a particular purpose come into existence in a 

 purely mechanical way without the co-operation of a final cause 

 acting with a particular purpose ? " — the same riddle the solution 

 of which we account to be Darwin's highest philosophical merit. 



Among all the great philosophers of clas-ical antiquity, the 

 three we have already named, Anaximander, Heraclites, and 

 Empedocles, are undoubtedly those who have most clearly enun- 

 ciated the most important elements of the monistic theory 

 of nature now prevalent. But besides these we find other 

 contemporaries of theirs who held similar conceptions of deve- 

 lopment, such as Thales, Anaximenes, Democritus, Aristotle, 

 Lucretius, &c. Yet were these various attempts at a genetic 

 theory of nature soon thrust into the background by an opposing 

 scheme of the world, that, namely, of the " Philosophy of 

 Ideas," which was propounded by the sophists, and had its 

 centre in Plato. 



If these fresh minded experimentalists of Ionian philosophy 

 sought to explain the totality of the world by natural causes through 

 mechanical processes, the Platonic school set up, in opposition to 



this view, supernatural cau=es, in the form of teleological ideas. 

 There thus arose a mode of thought and inquiry which, with- 

 e miad from the objective knowledge of nature, 

 placed the subjective being of man in the forefront of our con- 

 templations, a mode which throughout a space of more than 2000 

 years exerci-ed its baleful influence in ever increasing 

 In complete contradistinction to the "Unity of Nature," every- 

 where demonstrated by the causality of her phenomena, there 

 developed mightily the dualism invented by Plato, a harsh anti- 

 the-is between God and world, between idea and matter, be- 

 tween force and stuff, between soul and body. The numerous 

 forms of organic nature which we distinguish as animal and 

 vegetable species no longer appear as different stages in the 

 tent of common original forms, but as embodiments of 

 si many innate, eternal and unchangeable " ideas," as "con- 

 — 1 . as Agassiz, Darwin's greatest opponent, 

 expressed it. " embodied creative thoughts of God." 



This 1 latoni-m found its strongest support in the dogmas of 

 Christianity which preaching retirement from nature came 

 into friendly agreement with the " philosophy of ideas." The 

 accelerating decline, again of the sciences which followed the tragic 

 destructi in of noble Hellenism operated in favour of both Pla- 

 Christianity. Throughout the whole long spiritual 

 night of the Christian Middle nges there was no inward impulse to 

 a monistic theory of nature on the ground of experimental inves- 

 tigation. In truth, however, there were not wanting attempts 

 in this direction on the ground of pure speculation. In par- 

 ticular, the Pantheistic systems of Giordano Kruno and of 

 Benedict Spinoza in the sixteenth and seventeenth centuries 

 are admirable essays towards a monistic and natural com- 

 prehension of nature. These Pantheistic cosmologies, however, 

 which in all material things assume an impelling world-soul in 

 inseparable unity, were yet especially directed on the province of 

 ethics or practical philosophy, and lacked, alas too desperately, 

 all experimental foundation through immediate observation ot 

 nature— for in truth there was then no such thing. The whole 

 sense and tendency of most thinkers of that time were turned 

 away from Nature and bent exclusively on man, who was con- 

 sidered to hold a position beyond and above Nature. Even 

 those monistic sy-tems, therefore, of Bruno and Spinoza had no 

 power to establish themselves in the face of the all-mighty 

 dualism which, through Platonism and Christianity, attained to 

 universal supremacy. 



Not till a long period afterwards, not till the middle of the 

 last century, did the natural reaction against that dualistic scheme 

 of the world finally assert itself. Then at length did man begin to 

 turn to the true source of all knowledge, to nature herself. Espe- 

 cially in regard to the knowledge of animate bodies in nature, 

 knowledge which had hitherto for two thousand years been 

 drawn almost exclusively from the well of Aristotle, a new era 

 of independent observation sprang up. The outward form and 

 inward -tincture of plants and animals, their vital phenomena, 

 and their development were now for the first time the subject of 

 zealous and extensive investigation on the part of numerous 

 naturalists. The plenitude of interesting facts which this source 

 of natural revelation supplied could not, however, but again 

 excite inquiry after the efficient causes, and soon the idea ot 

 natural deve'opment as an answer to the que-tion forced its way 

 out again. 



The so-called school of the " older philosophy of nature, to- 

 wards the end of the last and the beginning of the present century, 

 first appears, simultaneously in Germany and France, a* the new 

 banner-bearer of this idea. But independently of this school, we 

 see a number of the greatest thinkers and poets of our classical 

 literary period moved by the same idea, above all Goethe, 

 Lessing, Herder, Kant ; later, Schelling, Oken, and Treviranus. In 

 France, again, we notice Lamarck, Geoffroy St. Hilaire, and Blain- 

 ville ; in England Erasmus Darwin, the grandfather of our reformer 

 who, in accordance with the laws of latent heredity, transmitted 

 a whole series of characteristic intellectual qualities to his grand- 

 son. Time does not allow us to-day to follow w ith a view towards 

 cona.pari-.on of the different expressions of the conception of deve- 

 lopment in these eminent thinkers, and, besides, much in this 

 respect is already universally known. We will on this occasion 

 confine our attention to two of the most eminent minds, to 

 Goethe and Lamarck — as in our opinion, of all Darwin's prede- 

 cessors, they are the most important. 



The significance of Goethe as naturalist has in oar time been 

 so often" and so searchingly treated by several of our most 

 esteemed biologists, that we may assume the most of it also to be 



