TEE COURSE OF NATURE. 



4S1 



THE COURSE OF NATURE. 



AN ADDRESS BEFORE THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT 

 OF SCIENCE, AT ST. LOUIS, AUGUST 22, 1878. 



Bt Professor SIMON NEWCOMB, President. 



IN imposing on its retiring president the duty 

 of delivering an address, the constitution of 

 this society gets no limits to his choice of a theme. 

 Both in this and in the sister society of Great Brit- 

 ain it has not been uncommon for the speaker to 

 choose for his subject the general progress of 

 scientific research during the year. This course 

 is now less common than formerly ; because, ow- 

 ing to the immensity of the field of research, it 

 has become impossible for any one mind to fol- 

 low its progress in all its branches. I have, there- 

 fore, thought that a higher interest would attach 

 to a theme chosen from the field of modern scien- 

 tific thought, and, by a process in which I have 

 been the follower rather than the leader of my 

 own contemplations, I have been led to present 

 to you some thoughts on the course of Nature as 

 seen in the life of modern scientific and philo- 

 sophic research. Though I have but a single 

 central idea to present to you — namely, that of 

 the simplicity and universality of the laws of 

 Nature — yet so great is the confusion of thought 

 which prevails on the question, " What are laws 

 of Nature ? " that it is necessary to approach my 

 idea from more than one standpoint, and to illus- 

 trate it in more than one way. 



We all know that the history of the Caucasian 

 race during the last three centuries has been 

 marked by a kind of intellectual development so 

 entirely without precedent that some might call 

 it miraculous ; in fact, by such a development of 

 the understanding of the course of Nature as has 

 revolutionized human society in many of its 

 phases. You also know that this development 

 has been marked by frequent collisions of opinion 

 between the investigators of the material mani- 

 festations of Nature, on the one side (if I may be 

 allowed to use the expression), and philosophers 

 and theologians, on the other, respecting the true 

 theory of the course of Nature. My desire, in 

 entering this field, is to act the part of the peace- 

 maker, rather than that of a combatant, not sus- 

 taining any other propositions than those which 

 are actually believed in by the large majority of 

 educated men at the present time ; but the con- 

 fusion of thought on this subject, to which I have 

 103 



just alluded, is so great that, although I may 

 combat no opinions actually held, it may be 

 necessary to greatly modify their application and 

 to criticise the forms in which they have found 

 expression. 



The key-note of my discourse is found in a 

 proposition which is fundamental in the history 

 of modern science, and without a clear under- 

 standing of which everything I say may be en- 

 tirely misunderstood. This proposition is, that 

 science concerns itself only with phenomena and 

 the relations which connect them, and does not 

 take account of any questions which do not in 

 some way admit of being brought to the test of 

 observation. The only universe it knows is that 

 made known by the telescope, the microscope, 

 and other appliances of observation. That this 

 is the whole universe we should all be very sorry 

 to suppose, and none more so than he who has 

 the honor to address you. But, should I pretend 

 to a scientific knowledge of what lies behind this 

 visible frame, I should be acting the part of the 

 rash speculator, rather than that of the cautious 

 thinker. Only into a single field of thought do I 

 dare to venture. When we trace the efforts of 

 men to penetrate the secrets of Nature, we find 

 them clearly divisible into two classes — philo- 

 sophic speculation and scientific investigation. 

 We find the objects of thought equally divisible 

 into two classes— phenomena and their hidden 

 causes, those unknowable entities out of which 

 they proceed. The great progress which the last 

 three centuries have witnessed has been wholly 

 in the field of phenomena, and it is to this field 

 and to the results of scientific investigation in it 

 to which I ask your attention this evening. But 

 it is to be expected that in this brief character- 

 ization of our field of thought I have failed to 

 convey to your minds any clear conception of 

 its boundaries. The progress here alluded to 

 has been rendered possible only by entirely re- 

 jecting the mode of thinking about Nature which 

 was prevalent in former ages, and into which 

 the untrained mind is almost sure to fall at the 

 present day. The distinction will be evident at 

 a glance to one mind, while another may be un- 



