LIMITS OF OUR KNOWLEDGE OF NATURE. 23 



holtz with the aid of the mechanical theory of heat, leads to a con- 

 ception of the origin of our planetary system. We lirst see our earth 

 revolving in its orbit as a glowing fluid drop with an atmosphere of un- 

 definable constitution. In the course of immeasurable intervals of 

 time we see it become coated over with a crust of indurating primor- 

 dial rock ; sea and land are divided, eruptions of hot carbonic acid 

 break up the granite, and give material for strata of alkaline earths, 

 and finally the conditions arise under which life became possible. 



Where and under what form life first appeared, whether at the bot- 

 tom of the deep sea, as bathybius protoplasm, or whether with the co- 

 operation of the still excessive ultra-violet solar rays, with still higher 

 pressure of carbonic acid in the atmosphere, who can tell ? But La- 

 place's Mind could tell, with the aid of the universal formula. For, 

 when inorganic matter coalesces to form organic matter, there is only 

 a question of motion, of the arrangement of molecules into states of 

 more or less stable equilibrium, and of an exchange of matter pro- 

 duced partly by the tension of the molecules, and partly by motion 

 from without. What distinguishes living from dead matter, the plant 

 and the animal, as considered only in its bodily functions, from the 

 crystal, is just this : in the crystal the matter is in stable equilibrium, 

 while a stream of matter pours through the organic being, and its 

 matter is in a state of more or less perfect dynamic equlibrium, the 

 balance being now positive, again approaching zero, and again nega- 

 tive. Hence, without the interference of extraneous masses and forces, 

 the crystal will remain forever what it is, whereas the organic being 

 depends for its existence on certain exterior conditions, transforms 

 potential into kinetic energy, and vice versa, and has a definite dura- 

 tion in time. Thus we see, that though there is no fundamental dif- 

 ference between the forces operating in the crystal and in the organ- 

 ized being, still the two are incommensurable, just as a simple building 

 is incommensurable with a factory into w^hich coal, water, and raw 

 material pass, on this side, while at the other side carbonic acid, water, 

 vapor, smoke, ashes, and the products of the machinery, are sent out. 

 The building we may regard as so made up of parts, each resembling 

 the total result, that, like the crystal, it is separable into like parts ; 

 the factory, like the organic being (if we abstract from the cellular 

 constitution of the latter, and the divisibility of sundry organisms), 

 is an Individual. 



It is therefore an error to recognize, in the first appearance of liv- 

 ing things on the earth, any thing supernatural, or any thing else save 

 an exceedingly difiicult mechanical problem. This is one of the two 

 errors to wich I proposed to call attention. The other limit of natu- 

 ral science is not here, any more than in the fact of crystallization. 

 Were we able to create the conditions under which organic beings 

 had their rise, which we are not even able to do for all crystals, then, 

 according to the principle of actualism, we could produce organic 



