IV. THE PHYSICS OF CONSCIOUSNESS- 

 MENTAL MECHANICS. 



" One herd of ignorant people, with the sole prestige of rapidly- 

 increasing numbers, and with the adhesion of a few fanatic deserters 

 from the ranks of science, refuse to admit that all the phenomena even 

 of ordinary dead matter are strictly and exclusively in the domain of 

 physical science. On the other hand, there is a numerous group, not 

 in the slightest degree entitled to rank as physicists though in general 

 they assume the proud title of philosophers who assert that not merely 

 life, but even volition and consciousness are mere physical manifesta- 

 tions. These opposite errors, into neither of which is it possible for a 

 genuine scientific man to fall, so long at least as he retains his reason, 

 are easily seen to be very closely allied. They are both to be attributed 

 to that credulity which is characteristic alike of ignorance and of in- 

 capacity. Unfortunately there is no cure the case is hopeless ; for 

 great ignorance almost necessarily presumes incapacity, whether it 

 shows itself in the comparatively harmless folly of the spiritualist, or in 

 the pernicious nonsense of the materialist." Prof. P. G. Tait, Report 

 of Meeting of Brit. Ass., Edinburgh, 1871. " Nature," Aug. 3rd, 

 1871, p. 273. 



THE interest to the general reader of the most important 

 scientific problems discussed in this volume is without 

 doubt mainly due to the influence which reputed solutions 

 of them have exerted, and are supposed to continue to 

 exert, in modifying the views hitherto accepted by the 

 majority of thoughtful and studious persons, upon first prin- 

 ciples which seem to form the basis of religion and philo- 

 sophy. But a correct appreciation of the real importance 

 of many scientific inferences which are considered to be 



