152 THE POPULAR SCIENCE MONTHLY 



that force, or energy, energy that can be measured, harnessed, made to 

 do work, exists in matter, and that no satisfactory account of nature 

 can be given which overlooks or neglects it. In these abstract theories 

 we proceed from small beginnings and build up our theories upon con- 

 clusions which seem to be true. The great names connected with them 

 are Newton, Lagrange, Fresnel and Helmholtz. In the concrete 

 theories objects are found ready made. We take them as they are and 

 seek to describe them, and give a reason for their distribution and for 

 their existence. Hence the theory which occupies itself with forms, or 

 the morphological theory. ISTor is it less a matter of interest to know 

 how these forms have originated, out of what materials and under what 

 conditions. Hence the genetic theory, which is supported by an array 

 of names the scientific world delights to honor. With the study of 

 biology, or life, it is natural that there should be a vitalistic theory, 

 and that in process of time the student should discover a border land 

 between mind and matter subject in part to physical, in part to mental 

 laws. So we have the psychophysical theory of the universe, and the 

 deep and growing interest in the study of its problems. Yet however 

 true each of these theories is, and there is truth in them all, it is cer- 

 tain that as science enlarges her borders, opens new fields of knowledge, 

 these theories will be given up, or be modified to such an extent as to 

 be virtually new, that the study of nature and her processes will con- 

 tinue to the end of time and that whatever advantages the man of 

 science may have one thousand or ten thousand years hence, the prob- 

 lems then demanding solution will be neither less numerous nor less 

 difficult than those which confront him to-day. 



Yet these studies are of great value, not only for the practical bene- 

 fit they bring to the world, but for the influence they have on those who 

 pursue them. They teach men to be tolerant, for the fields to be 

 traversed are so wide, the subjects considered are so varied and com- 

 plex, and are cultivated with such diverse aims, that one can not be 

 surprised at the different conclusions to which investigators, equally 

 in earnest and equally competent, arrive. In a scientific mind dogma- 

 tism has no place. Love for old truth does not prevent hospitality 

 toward that which seems to be new. Scientific studies are fitted by their 

 very nature to produce enlargement of mind, clearness of vision and 

 devotion to the search after truth. The man of science is not only far 

 better prepared for his studies to-day by the mental attitude he is com- 

 pelled to assume in beginning his special work than ever before; the 

 equipment at his disposal is more complete and better adapted to his 

 wants than his predecessors have enjoyed. Indeed, he is in this respect 

 the heir of all the ages. It is his own fault if he is irreverent toward 

 old truth, inhospitable toward that which is new, or lacking in devotion 

 to search after that truth with which nature is full and is waiting to 

 reveal. 



