534 



NATURE 



\Oct. i8, 1877 



would be uncertain for it, and the future as well as the past 

 would be present to its gaze. The human mind, in the perfection 

 whxh it has been enabled to give to astronomy, offers a weak 

 reflection of a mind of this description." 



But even a mind as universal as that supposed by Laplace 

 would not be able to solve the problem given. Because the 

 other supposition, of which Laplace does not speak, but from 

 which he starts unconsciously, is the finiteness of the world in all 

 directions, and this is not given. Tlie difficulty which nature 

 opposes to human knowledge is her endlessness, endlessness of 

 space and of time, and of everything which depends on this as 

 a necessary consequence. 



In space nature is not only infinitely large ; she is endless. 

 The ray of light travels through some 190,000 miles in 

 one second ; to travel through the wliole known universe 

 of fixed stars it would require some twenty million years accord- 

 ing to a probable estimate. Let us place ourselves in thought at 

 the end of this immeasur.ible space, upon the farthest fixed star 

 known to us, then we would not lookout into empty space there, 

 but we would see a new starry firmiment. We would again believe 

 that we were in the middle of the universe, in the same way 

 as now the earth appears to us as the centre of the universe. 

 And thus we may in thought continue endlessly the flight from 

 the farthest fixed star to the farthest fixed star, and the actual 

 starry heavens we now see, compared to the universe, are alter 

 all still infinitely smaller than the smallest atom compared to the 

 starry heavens. 



What applies to space applies equally to grouping in space, 

 to the composition, organisation, and individualisation of matter, 

 which is the object of descriptive and morphological natural 

 science. Everything we know consists of parts, and is in itself 

 part of a. bigger whole. The organism is composed of organs, 

 these of cells, and the cells of smaller elementary particles. If 

 we analyse further we soon get to chemical molecules and the 

 atoms of chemical elements. The latter certainly still resist 

 further subdivision at present, but we must nevertheless look 

 upon them as compound bodies on account of their properties. 

 Thus in thought we may continue sub-division further and end- 

 lessly. In reality no physical atoms in the strict sense of the 

 word can exist, no little particles which would really be indi- 

 visible. All size, indeed, is only relative ; the smallest body 

 in existence which we know, the particle of the light-and-heat 

 ether may be of any size we choose for our conception, even infi- 

 nitely large, if only we imagine ourselves to be sufficiently small 

 by the side of it. Just in the same way as indivisibility never 

 ceases, we must suppose, by analogy of what we find confirmed 

 in the whole domain of our experience, that the composition also 

 of individual particles separated from one another, continues 

 endlessly downwards. In like manner we are forced to sup- 

 pose an endless composition upwards in always larger, individual 

 groups. The heavenly badies are the molecules which unite in 

 groups of lower and higher orders, and the whole of our system 

 of fixed stars is only a molecular group in an infinitely larger 

 whole, which we must again suppose to be a unit (eiiiheitlichcr) 

 organism, and only a particle o( a still larger whole. 



As space is endless in all directions, so time is endless on two 

 sides ; it has never begun and will never cease. The Bible says : 

 "In the beginning God created heaven and earth,'' and geologists 

 say: "Inthebegmning the world was a gaseous mass, from which 

 heavenly bodies formed by condensation." But this beginning 

 is only a relative one, the beyinning of a finiteness, and the 

 time which has passed since this beginning is only as a moment 

 compared to the eternity before. 



From the union of time and space an empire of phenomena 

 results, which forms the contents of descriptive natural sciences 

 as well as of the other part of the investigation of nature, viz., 

 the physical and physiological sciences. Matter, which fills 

 space, is not at rest but in motion, and as the material particles 

 act upon one another with different (attractive and repulsive) 

 forces, each body which moves causes the others to move as 

 well, or rather it changes their motions. It gives off a part of 

 its motion and of its potential energy to others, and these again 

 to others, and so on. This is the chain of cause and effect, also 

 an endless one,. as in our conception it neither could begin with 

 a first cause nor can finish with a last effect. 



Nature is everywhere uninvestigable where she becomes endless 

 or eternal. We cannot, therefore, conceive her as a whole, 

 because a process of conceiving which has neither beginning nor 

 end, does not lead to conception. And this is the reason why 

 Laplace's problem is futile from the beginning. Of course we 

 are permitted to make any supposition we like, even one which 



for some reason or other is impossible, but not one which is 

 unthinkable. But a formula is unthinkable for which we have 

 not even got the component factors, and which if these factors 

 were given, would never come to an end. The knowledge 

 of all forces, which is required for Laplace's formula, sup- 

 poses that the bodies are subdivided down to their last force- 

 endowed particles, and this is impossible on account of divisi- 

 bility being endless. The elements therefore are wanting, from 

 which we might compose the formula, viz., the simple natural 

 forces ; we cannot even begin with the setting of the formula 

 — and even if we could begin with it we could never come to an 

 end with it on account of the endlessness of the universe in space. 

 Du Bois Reymond has already mentioned the former endlessness 

 as an insuperable limit ; even if we could overstep it, the other 

 would still prove equally insuperable. 



If indeed the foimula of Laplace comprised only the universe 

 known to our senses, or even one infinitely larger (but not one 

 really endless), and if we could introduce into this formula the 

 forces of the known chemical elements and of the supposed ether 

 particles, or even of much smaller material particles, then it 

 might perhaps suffice for long periods of time backwards and 

 forwaids from the present, particularly for the middle of the 

 system and for the greater phenomena. But on the one hand 

 disturbances from the circumference would at once necessarily 

 take place, and these would at last render the formula useless for 

 the middle als5 ; on the other hand, disturbances would begin 

 on each single point as well, and as they would increase 

 constantly, they would at last lead to perceptible inaccuracies, 

 because the supposed " atoms," are not real unities, and because 

 the resulting force, with which each single "atom," as a body 

 composed of separate particles, influences the totality, does not 

 remain a constant one, but with its varying surroundings assumes 

 at every moment an equally varying value. Anyhow, a lormula 

 of this kind would give us, as astronomical calculation really 

 does, a solution, correct within certain limits, a practical 

 solution, but not a fundamental one. 



The investigator of nature must remember distinctly, that all 

 his investigations are confined by limits in all directions, that 

 on all sides uninvestigable eternity bids him categorically to stop. 

 The fact that this has not always been clearly recognised, that 

 particularly the Infinitely Large and the Infinitely Small have 

 been mixed up with Endlessness and Nothing, has led to several 

 erroneous conceptions. Amongst them are the theories of physi- 

 cal atoms in the one direction, and those of beginning and end 

 of the universe in the other. I will only speak of the latter. 



It is supposedjthat the matter constituting the lieavenly bodies 

 was in the beginning distributed in a gaseous state ; and in this 

 Du Bois Reymond only finds one difficulty : if this matter, as 

 the theory demands, had been at rest and distributed equally, 

 he cannot find out whence motion and unequal distribution have 

 come. 



Condensation of matter has now gone on for an infinite time, 

 i.e., since that supposed beginning, and the results are first 

 nebuUe, then burning-liquid drops, which cool down to dark 

 bodies. In the present we are upon one of these condensed, 

 and no longer incandescent world-drops. According to the 

 natural laws known to us, the still incandescent and the already 

 dark heavenly bodies must continue to. give off their store of heat 

 to universal space. By and by they must fall upon one another, 

 and even if then a local rise in temperature again takes place, 

 this after all only serves to accelerate the process of cooling on 

 the whole. At last all heavenly bodies will unite in a dark, 

 solid, icy mass, upon which there is no longer any motion nor 

 life. 



This is the result of a correct physical consideration. It shows 

 us the desolate end of a present full of change and motion and 

 glowing with life and colour. But in reality this result is only 

 the cunscquence of our confined human insight ; it would only 

 be a logical necessity if we knew r^-erything, and therelore were 

 aUowed to use our knowledge for deductions with regard to the 

 beginning and end. But as we see only an infinitesimal part of 

 the universe, and possess only a fragmentary knowledge of the 

 forces and forms of motion in this infinitesimal part, our deduc- 

 tions backwards and forwards may perhaps for ceitain general 

 conditions be without perceptible error for billions of years, but 

 yet, with the lapse of greater periods of time, they must become 

 more uncertain, and eventually totally erroneous. We may 

 illustiate this particularly well with regard to the past. 



What we are most certain of, with regard to the past, is the 

 incandescent state in which our earth was at one period, and from 

 this we draw the conclusion by analogy that the other planets of 



