234 The Intellectual Revolution 



last to reach the social and spiritual heights corre- 

 sponding to the progress which has been made in 

 the mastery of the material universe. 



In philosophy we had an intellectual revolution 

 in the time of Immanuel Kant, when men turned 

 away from the external universe as the essential 

 truth and found instead the mind and the spirit 

 of man as the eternal reality. Kant's critical study 

 of the laws of the mind, and of the senses by which 

 we perceive the manifestations of nature, led to a 

 marvellous extension of the power of man to 

 understand the universe, and is the threshold 

 from which modern philosophy starts on its 

 quest for the Holy Grail of Truth. 



In the same way in the social revolution, by 

 turning away from the struggle of physical force 

 in the external world and concentrating our 

 energies instead upon the struggle for truth and 

 justice in the intellectual realm, we shall be open- 

 ing the way for a reconstruction of our social 

 institutions upon rational lines, and in conformity 

 with the true principles of human relationships 

 which emerge as the result of this intellectual 

 struggle. 



In astronomy the intellectual revolution which 

 marked the change from the old Ptolemaic sys- 

 tem, in which the earth was considered as the 

 centre of the planetary system, to the true or 

 Copernican system in which the sun became 

 the centre, illustrates most clearly the nature 

 of the present intellectual revolution, in which 



