126 WHAT IS LIFE 



one form of energy is changed into another, nothing 

 is lost nor is anything gained. Consequently the 

 following so-called "laws" have been formulated 

 by men of science : 



1. That the sum of the kinetic and potential 

 energies of any isolated system of bodies remains 

 constant ; and 



2. That the sum-total of the energy in the 

 universe remains the same. 



Before considering the bearing of these laws on 

 the question under consideration it will be well to 

 be quite clear in our minds as to what is meant by 

 a law of nature and what its precise value is. 



The word "Law" has two distinct meanings, 

 not unfrequently confounded. Sometimes the term 

 stands for a decree or command, expressed by a 

 sentence in the imperative mood. The Ten Com- 

 mandments and Acts of Parliament are " laws " in 

 this sense. At other times the term denotes some 

 observed uniform mode of action or behaviour in 

 phenomena which is signified by a general pro- 

 position in the indicative mood. The laws of 

 chemistry and astronomy are examples. Now it 

 Laws of cannot be too clearly kept in mind that the " laws 

 Nature of Nature are o f this latter kind. 



The term simply expresses our appreciation or 

 conception of an orderly or supposed orderly se- 

 quence of events in the natural world. Viewed 



