88 INTRODUCTION TO SCIENCE 



by joining the first in solving the problems of the 

 third. All along there has been a continuous 

 action and reaction between the three great classes 

 of sciences." 



SPENCER'S SCHEME 



Group I. Abstract Sciences: LOGIC AND MATHEMATICS 

 Group II. Abstract-Concrete Sciences: Mechanics, Phy- 

 sics, Chemistry 



Group III. Concrete Sciences : Astronomy, Geology, Biol- 

 ogy, Psychology, Sociology 



"The three groups of Sciences may be briefly 

 defined as laws of the forms, laws of the factors, 

 laws of the products." 



"The first, or Abstract group, is instrumental 

 with respect to both the others; and the second, 

 or Abstract-Concrete group, is instrumental with 

 respect to the third or Concrete group." 



"The second and third groups supply subject- 

 matter to the first, and the third supplies subject- 

 matter to the second; but none of the truths 

 which constitute the third group are of any use 

 as solvents of the problems presented by the 

 second group; and none of the truths which the 

 second group formulates can act as solvents of 

 problems contained in the first group." 



In this scheme, as Prof. Flint pointed out, 

 "Spencer would seem to have himself constructed 

 a series of sciences of the very kind which, in 



