time: the refreshing river 



to apply the principle that all physical events develop in one 

 direction only, to biological evolution; a singularly unhappy 

 attempt so long as the term evolution is associated with the 

 idea of progress, perfection, or improvement. The principle of 

 entropy is such that it can only deal with probabilities, and all 

 that it really says is that a state improbable in itself, is followed 

 on the average by a more probable state. Biologically interpreted, 

 this principle points towards degeneration rather than improve- 

 ment. The chaotic, the ordinary, and the common, is always 

 more probable than the harmonious, the excellent, or the rare."^ 



And yet, in spite of these difficulties, and the general trend towards 

 probable disorder, the rise in level of organisation during evolution 

 has in fact occurred. 



Patterns in the non-living world. 



We come now to certain reflections which seem to suggest rather 

 strongly that the thermodynamic principle of order is indeed funda- 

 mentally diflferent from the biological principle of organisation. 

 Biological organisation depends universally upon aggregations of 

 particles, of high complexity. The molecule of protein, to say nothing 

 of the paracrystalline protein micelle, is an entity so complex that 

 though our analysis of it has begun, we are not as yet in sight of a 

 clear understanding of it. Now although biological organisation, as 

 we have seen, depends everywhere on a continuing metabolic upkeep, 

 energy entering the plant as light or the animal as chemical energy 

 in the foodstuffs, and being degraded in combustions and dissipated 

 as hea-c; biological organisation is only the extrapolation of patterns 

 already to be found in the non-living world. We cannot make any 

 sharp line of distinction between the living and the non-living. 

 At the level of the sub-microscopic viruses, they overlap. Some 

 particles show some of the properties of life but not others. Some 

 "dead" protein molecules are much bigger than the particles of some 

 "living" viruses. Particles which show the properties of life can be 

 had in paracrystalline, and even in crystalline form. There are many 

 similarities between the morphology and behaviour of crystals and 

 living organisms.^ 



Among the patterns found in the non-living world, crystalline 



^ M. Planck, The Philosophy of Physics (London, 1936), p. loi. 



^ Cf. such books as H. Przibram, Die Anorganische Grenigebiete d. Biologic (Berlin, 

 1926), and F. Rinne, Grenifragen des Lebens (Leipzig, 1931). 



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