THE PHYSICAL UNIFERSE 3 



we do not know what forms of spiritual existence may 

 .be possible, we can positively state that life, in the 

 ordinary acceptance of the word, is possible in only an 

 infinitesimal portion, relatively speaking, of the uni- 

 verse. It is practically certain that the earth is the 

 only planet of the solar system which can support 

 life, as we know it. Even if we assume (it is pure 

 assumption) that there are other systems wherein 

 life exists, the whole life-bearing surface must be so 

 small a part of space that it cannot be expressed in 

 intelligible mathematical terms. There are also good 

 reasons for limiting the duration of life, so that its 

 existence on any globe belongs to only a minute frag- 

 ment of the time which the astronomer recognizes as 

 representing the minimum required for the evolution 

 of the universe. Life, then, is the most unique and 

 exceptional phenomenon, or group of phenomena, in 

 the material universe ;. and had it been possible for 

 a scientific being to study nature prior to or outside 

 of the existence of life areas, he could hardly have 

 predicted or expected living beings, much less those 

 conscious of their own existence. 



5. Asking how life originated, and what it is, we Matter and 

 must first determine the conditions under which it is 

 manifested. The physical universe is said to consist 

 of matter, but this "matter" is known to us only 

 through its manifestations of energy, all of which 

 consist of movements during time, through space. 

 These movements may be gross and visible, or exces- 

 sively minute, such as those producing heat, or bringing 

 about chemical changes. Although an object such as 

 this book may be said to be stationary, as it rests upon 

 the table, its minute particles are actually in motion. 

 The totality of matter is said to be constant, and also, 



