[118] Cours, III, 93. [119] Cours, II, 16-17. [120] Cours, II, 14-15. [121] Pol. pos. I. 500. [122] Cours, II, 153. [123] Cours, II, 132-3. [124] Cours, VI, 751. [125] Cours, II, 133. [126] Cours, II, 266-7. [127] Cours, II. 7. [128] Cours, VI, 751. [129] Pol. pos. I, 508. [130] Pol. pos. IV. 212. [131] Pol. pos. I. 508-13. [132] Cours. II. 297. [133] Cours II. 310. [134] Pol. pos. I, 516-18. [135] Cours, II, 313-15; Pol. pos. I, 519. [136] Cours, II, 317. [137] Cours, II, 321. [138] Cours, II, 336 sq. [139] Pol. pos. 520. [140] Pol. Pos., I, 532. [141] Cours, III, 3-4. [142] Cours, III, 186-9. [143] Cours, III, 195. [144] Cours, I. 118: II. 311. [145] Cours III. 11-12. [146] Cours, III. 206. [147] Cours, III. 35. [148] Cours, III. 87-8. [149] Pol. pos. I. 551. [150] Cours, II. 24-26. [151] Cours, II. 331. [152] Cours, III. 75. [153] Pol. pos. I, 561. CHAPTER IV BIOLOGY The passage from the inorganic world to the world of Life constitutes a critical step in natural philosophy. Astronomy, Physics, and Chemistry represented successive steps in the same series. If each order of phenomena presented in itself something which was irreducible to previous orders, nevertheless all these phenomena, in a certain sense, remained homogeneous. Without rashness, Descartes could conceive that physics, like astronomy, would one day assume the mathematical form. And to-day more than one scientific man considers the distinction between physics and chemistry as provisional. But as soon as life appears, we enter a new world. At this degree the “enrichment of the real” is suddenly so considerable that we find it difficult to admit the homogeneity of these phenomena with the preceding ones. Comte here reaps the benefit of his prudence. His philosophy has guarded against reducing all science to a single type, and it is content with the unity of method and the homogeneity of doctrine. It only demands that each science should limit itself to the search after the laws of phenomena. As to the way in which this research is to be carried out, it is evidently subordinated to the nature of the phenomena in question. Now, biological phenomena present a number of characteristics which belong to them alone, and the first duty of the positive science which studies them is to respect their originality.