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LXI. Notices respecting New Books. 



An Enquiry concerning the Principles of Natural Knowledge. By 

 A. N. Whitehead. Sc.D., F.E.IS. Cambridge : The University 

 Press, 1919. 



Professor Whitehead's book has made its appearance at a very 

 fortunate moment. He could not have anticipated that a few 

 months after its publication the verification or a prediction in 

 regard to an astronomical event would be astonishing the intel- 

 lectual world and setting everyone trying to understand the 

 revolution it implies in our fundamental concept of Nature. It is 

 this fundamental concept and the principles on which we must, in 

 view of recent developments of science, in future base our physics, 

 which are investigated in this most fascinating Enquiry. 



Professor Whitehead's mathematical followers will no doubt 

 complain that so large a part of the book deals with metaphysics ; 

 his philosopher friends, on the other hand, may be appalled at the 

 intricate mathematical maze into which they will seem to be 

 uuheedingly conducted. The conception that physics and meta- 

 physics are one identical problem is, however, the dominating 

 thought in science and philosophy to-day, and it finds clear 

 expression in this book. 



The main thesis can be briefly stated. It is that the traditional 

 concept which has hitherto subtended the structure of physical 

 science, the concept of all nature at a durationless instant, is no 

 longer possible. The simple attempt to realize it in thought 

 makes everything that is anything in science meaningless. There 

 is no alternative in science but to abandon it, and replace it with 

 a new fundamental concept of which duration is the essence. 

 Nature does not consist of facts, that is, of material space- 

 occupancy at definite moments of time, but of events. Nothing 

 which is not event has any place whatever within the reality of 

 nature. This has been clear from the first in biology but it has 

 waited long for recognition in physics, and indeed all the attempts 

 to base biology on physics have been conceived with the idea that 

 the reality of physics is fundamentally different and more elemental. 

 The theory of the electro-magnetic origin of mass has revolutionized 

 the metaphysics of physics. " The modern theory of the molecule 

 is destructive of the obviousness of the prejudgment in favour of 

 the traditional concepts of ultimate material at an instant. Con- 

 sider a molecule of iron. It is composed of a central core of 

 positive electricity surrounded by annular clusters of electrons, 

 composed of negative electricity and rotating round the core. No 

 single characteristic property of iron as such can be manifested 



at an instant Iron and a biological organism are on a level 



in requiring time for functioning. There is no such thing as iron 

 at an instant ; to be iron is a character of an event." (5. 4.) 



It is curious to those of' us who are old enough to remember 

 the generation of the great Victorian men of science, to reflect orx 



