42 CEOONIAN LECTUKES 



state of our ideas regarding the union of matter 

 and force may be summed up in the following 

 formulae. Where matter is, there force must 

 be, showing itself in motion, or tension, or in 

 resistance. Without matter, no kind of motion, 

 nor tension, nor resistance, occurs. 



Turning now to the matters and forces in 

 those sciences in which the idea of life is con- 

 cerned, the question arises, What is the history 

 of the progress of our ideas regarding the union 

 of living matter and vital force ? 



As regards the biological sciences in general, 

 or as regards the biological knowledge which 

 each individual acquires, are these three stages 

 here also recognisable? First the complete, 

 and secondly the partial separation of our ideas 

 regarding living matter and living force ; and 

 is there a third stage, in which there is a 

 perfect inseparability of the ideas of matter and 

 force? Has our biological knowledge passed, 

 or is it passing, through these three stages? 

 Will the biological sciences follow in the foot- 

 steps of all other sciences? Will they share 

 with them in the extent and rate of progress 

 which will result from clearer and more con- 

 nected ideas regarding matter and force ? 



