14 INTRODUCTORY [ch. 



Some physicists declare, as Maxwell did, that atoms or molecules 

 more compHcated by far than the chemist's hypotheses demand, are 

 requisite to explain the phenomena of life. If what is impHed be 

 an explanation of psychical phenomena, let the point be granted at 

 once; we may go yet further and decHne, with Maxwell, to believe 

 that anything of the nature of physical complexity, however exalted, 

 could ever suffice. Other physicists, like Auerbach*, or Larmorj, 

 or Joly J, assure us that our laws of thermodynamics do not suffice, 

 or are inappropriate, to explain the maintenance, or (in Joly's phrase) 

 the accelerative absorption, of the bodily energies, the retardation 

 of entropy, and the long battle against the cold and darkness which 

 is death. With these weighty problems I am not for the moment 

 concerned. My sole purpose is to correlate with mathematical state- 

 ment and physical law certain of the simpler outward phenomena 

 of organic growth and structure or form, while all the while regarding 

 the fabric of the organism, ex hypothesi, as a material and mechanical 

 configuration. This is my purpose here. But I would not for the 

 world be thought to beheve that this is the only story which Life 

 and her Children have tp tell. One does not come by studying 

 living things for a lifetime to suppose that physics and chemistry 

 can account for them all§. 



Physical science and philosophy stand side by side, and one 

 upholds the other. Without something of the strength of physics 

 philosophy would be weak ; and without something of philosophy's 

 wealth physical science would be poor. "Rien ne retirera du tissu 

 de la science les fils d'or que la main du philosophe y a introduits||." 

 But there are fields where each, for a while at least, must work alone; 

 and where physical science reaches its limitations physical science 

 itself must help us to discover. Meanwhile the appropriate and 



* Ektropismus, oder die physikalische Theorie des Lebens, Leipzig, 1810. 



t Wilde Lecture, Nature, March 12, 1908; ibid. Sept. 6, 1900; Aether and Matter, 

 p. 288. Cf. also Kelvin, Fortnightly Review, 1892, p. 313. 



X The abundance of life, Proc. Roy. Dublin Soc. vii, 1890; Scientific Essays, 

 1915, p. 60 seq. 



§ That mechanism has its share in the scheme of nature no philosopher has 

 denied. Aristotle (or whosoever wrote the De Mundo) goes so far as to assert that 

 in the most mechanical operations of nature we behold some of the divinest 

 attributes of God. 



II J. H, Fr. Papillon, Histoire de la jyhilosophie moderne dans ses rapports avec le 

 developpement des sciences de la nature, i, p. 300, 1870. 



