EVOLUTION THE MASTER-KEY 



in many and diverse matters, scientific, artistic, 

 and political. Upon these he wrote numerous 

 essays, which were published in the chief reviews 

 during the fifth decade of the nineteenth century. 

 In 1852, for instance, he wrote an essay on the "De- 

 velopment Hypothesis," and, five years later, one 

 on ' ' Progress, Its Law and Cause. " He had not yet 

 seen reason to abandon the committed word prog- 

 ress for the neutral one now so familiar. Mean- 

 while, Spencer's more serious energies were devoted 

 to his book on psychology, which appeared in 1855, 

 an ever - memorable date in the history of the 

 science of mind. But hitherto there was no sign 

 of the emergence of a philosophic system. It was 

 not until Spencer had occasion to revise these very 

 miscellaneous essays for republication, and thus to 

 re-read them within a short period, that he dis- 

 covered, implicit within them, an inchoate philoso- 

 phy. And we may note that it was no more than 

 inchoate. The idea was not full - fledged, as in 

 the case of that celebrated piece of nonsense upon 

 which Hegel founded his philosophy "Being and 

 not-being are the same." It is true that the 

 evolutionary philosophy issued in a formula, but 

 it is not built upon it, as is Hegelianism upon the 

 aforesaid "synthesis." Evolution was not an a 

 priori truth, but a generalization from an infinitely 

 numerous and infinitely complex series of phenom- 

 ena. Though Truth is a whole, yet her architect- 

 ure is of immeasurable complexity, and thus the 

 formula of evolution, as we now have it, underwent 

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