vi SCIENTIFIC METHOD IN PHILOSOPHY 



mathematical physics. I have been made aware of the 

 importance of this problem by my friend and collaborator 

 Dr Whitehead, to whom are due almost all the differences 

 between the views advocated here and those suggested in 

 The Problems of Philosophy} I owe to him the definition of 

 points, the suggestion for the treatment of instants and 

 " things," and the whole conception of the world of 

 physics as a construction rather than an inference. What is 

 said on tjiese topics here is, in fact, a rough preliminary 

 account of the more precise results which he is giving in 

 the fourth volume of our Principia Mathematical It will 

 be seen that if his way of dealing with these topics is capable 

 of being successfully carried through, a wholly new light 

 is thrown on the time-honoured controversies of realists 

 and idealists, and a method is obtained of solving all that 

 is soluble in their problem. 



The speculations of the past as to the reality or un- 

 reality of the world of physics were baffled, at the outset, 

 by the absence of any satisfactory theory of the mathe- 

 matical infinite. This difficulty has been removed by the 

 work of Georg Cantor. But the positive and detailed 

 solution of the problem by means of mathematical con- 

 structions based upon sensible objects as data has only 

 been rendered possible by the growth of mathematical 

 logic, without which it is practically impossible to mani- 

 pulate ideas of the requisite abstractness and complexity. 

 This aspect, which is somewhat obscured in a merely 

 popular outline such as is contained in the following 

 lectures, will become plain as soon as Dr Whitehead's 

 work is published. In pure logic, which, however, will 

 be very briefly discussed in these lectures, I have had 



1 London and New York, 19 12 (" Home University Library"). 



2 The first volume was published at Cambridge in 19 10, the second in 

 1 912, and the third in 1913. 



