THE UNIVERSE AS A WORKING SYSTEM 239 



tively ; they are energetic and pushful, though not big. They occupy the atom in the sense that soldiers occupy 

 a country — that is, they will not let anybody else in. The electrons, by the force they exert, make the atom im- 

 penetrable ; they also give the atom its other properties, and enable it to act chemically. That chemical affinity 

 is electrical force has been known for a long time ; it was suspected by Sir Humphry Davy. The relation of the 

 electron to the atom is a matter of the most intense interest. But it is not to be supposed that the electron is 

 stationary in the atom. The electrons are revolving round one another at tremendous speed, so that the atom 

 is a region of intense activity. The electrons are not in the least crowded, although there are a thousand in the 

 hydrogen atom, twenty or thirty thousand in the sodium atom, and one hundred thousand in the mercury atom ; 

 for consider how far apart are they in proportion to their size — just as far apart as planets in the solar system 

 are in proportion to their size. The distance of the earth from the sun is to the size of the earth very much as 

 the distance of electrons from each other is to their size in a mercury or platinum atom. The fact is, we come 

 to an atomic astronomy, and the atom is becoming Uke a solar system, or like nebulae or Saturn's rings, composed 

 of a number of small particles in a violent state of revolving motion and occupying very Uttle of the whole space 

 with their actual substance. They are so small that collisions are unfrequent ; so it is in the solar system and 

 heavens generally — collisions do occur, but seldom, because of the excessively small sizes compared with the distances 

 at which they are spaced out. 



Taking any family belonging to a sun, that is, a solar system, it forms something like the same kind of 

 collection as the electrons form in an atom. So when we get in an atom a sort of solar system we begin to question 

 whether there is anything in absolute size after all. It has been suggested that solar systems may be atoms of a 

 still larger universe. These are questions that are too hard. But there appears to be no end to the infinity of 

 the universe, and all that we can say is that the probability is that it is infinite in an infinite number of ways. 



The account given above of the electrons of matter opens up an entirely new vista. It shows that the con- 

 sideration of even the most minute particle of matter indirectly raises the whole subject of the physical universe. 

 Similarly, a consideration of any of the attributes of spirit and mind raises these subjects more or less in their 

 totality : (a) as regards the divine mind ; (b) as regards the human mind and its representative in the lower 

 animals ; and (c) as regards the effect of both on matter. 



I cannot do better than close the present section with the words of Professor J. H. Muirhead, who regards 

 mind and matter, and vital and physical force, from two different standpoints. " If," he observes, " we set out from 

 the existence of mind and matter as two entirely separate substances, there is, it must be admitted, no way in which 

 we can establish continuity or causality between them. On the other hand, if we reverse this assumption, and regard 

 the conception of two worlds, a physical and a mental, as one that grows up within (it is not said created by) our 

 experience, a way seems opened up out of the difficulty. The conservation of energy and momentum, and the 

 determination of their direction by physical antecedents, are from this point of view conceptions which are forced 

 upon us in our endeavour to interpret to ourselves one side or aspect of our experience — that which we call the 

 mechanical. Within the area so describable they are universal, ultimate, admitting of no exception. But the 

 mechanical is only one side of our experience. Besides mechanical energy there is fife. The phenomena of life 

 violate no mechanical law, yet open up to us a new aspect of our world, a new form of ' energy.' We may, indeed, 

 try to ' explain ' life as only a more complex mechanism, and this has been a common device since the time of 

 Descartes. But the present-day tendency to recognise here a transitio in aliud genus, and to reject (as leading 

 to confusion) the attempt to explain the fuller, more concrete reality by formulae applicable only to the more 

 abstract, seems to be founded on a truer insight. What holds of the relation of life to mechanism holds also of 

 the relation of mind to life in general." 



From the foregoing it becomes more and more apparent that matter, force, fife, spirit, and mind are indissolubly 

 associated, and cannot be separated, even temporarily, for the purposes of argument. The one thing above all 

 others to be avoided is the taking of a part for the whole and the endeavouring to estabhsh weighty conclusions on 

 slender and inadequate premises. If the Creator made inorganic and organic matter. He of necessity made force, 

 physical and vital. He also made spirit and mind. The Creator is the fountain and source of everything, material 

 and immaterial, but it is not given to humanity to fully comprehend how force and Ufe are linked to matter, and 

 spirit and mind are associated, and how they interact as between themselves and the universe as a whole. It is 

 quite certain that no mere mechanical solution of the problem will suffice even as a working hypothesis. 



§ 44. Consideration of the Terms Irritability, Stimulation, Environment, and Instinct. 



The time has now arrived when these terms should be defined and used in a restricted sense or, what is better, 

 discarded. Their lax employment of late years has done much to discredit biology and physiology as exact 

 sciences, They have introduced confusion where none existed, and have made obscure, phenomena not naturally so. 



