220 ESSAYS OF A BIOLOGIST 



conscious, or has not been during our mental growth 

 incorporated to form an integral part of our private 

 personality. But this extra-personal part of the 

 mind may from time to time irrupt into the personal, 

 and does normally do so at some period of life. It 

 is the merit of psychology to have shown the true na- 

 ture of this relationship between personal and extra- 

 personal, which was in the past a source of an infinity 

 of mistaken ideas — revelation, inspiration, posses- 

 sion, direct communion with angels, saints, gods, or 

 devils, and so forth. 



Thus the powers operating in the cosmos are, 

 though unitary, yet subdivisible; and, though subdi- 

 visible, yet related. There are the vast powers of in- 

 organic nature, neutral or hostile to man. Yet they 

 gave birth to evolving life, whose development, 

 though blind and fortuitous, has tended in the same 

 general direction as our own conscious desires and 

 ideals, and so gives us an external sanction for our 

 directional activities. This again gave birth to hu- 

 man mind, which, in the race, is changing the course 

 of evolution by acceleration, by the substitution of 

 new methods for old, and by introducing values 

 which are ultimate for the human species; and, in 

 the individual, provides, in the interplay of conscious 

 and subconscious, unbounded possibilities of the in- 

 vasion of the ordinary and humdrum personality of 

 every day by ideas apparently infinite, emotions the 

 most disinterested and overwhelming. 



