FIRST PRINCIPLES 5 



whether the hypothesis will meet all cases. It is amplified 

 to make it include allied phenomena, or modified to prevent 

 it from excluding them. Perhaps it is rejected and re- 

 placed by an entirely different theory, because it cannot be 

 made to include phenomena which are evidently of the same 

 order as those for which in the first instance it seemed to 

 assign the cause. 



It is easier to give expression to the general conception 

 of science, as distinguished from knowledge, in metaphor 

 than in a reasoned definition, and many comparisons which 

 illustrate this welding together of facts with thought will 

 occur to everyone's mind. Knowledge is a pile of bricks, 

 science is masonry. Knowledge is a shower of separate 

 raindrops, science the mountain torrent to which they give 

 birth ; the forceful stream which carves canons in the rock, 

 traces a green band on the map, turns water-mills, fills the 

 reservoirs of dusty, dirty towns. Knowledge is discrete, 

 incoordinate, unsatisfying ; science is concrete, coordinate, 

 effective. With observation as the starting point, the mind 

 amasses knowledge, and knowledge, by provoking thought, 

 leads to the acquisition of fresh knowledge, out of which a 

 wider thoughtfulness builds a scientific system. 



The Aim of Science is to know Nature. As a mer- 

 chant takes stock of his goods before he makes plans for 

 placing them on the market, so the student of science must 

 make himself acquainted with the phenomena which Nature 

 exhibits, in the province which he has pledged himself to 

 explore, before he attempts to assign to them their several 

 uses. There is no fact, no detail of measurement, of con- 

 firmation, of colour, scent, taste or distinctive marking which 

 he dare overlook as too trivial for notice, however trivial may 

 be the use which at the time he can make of his observation. 

 All facts are great facts. Every observation which adds a 

 fact to the sum of human knowledge is a great discovery. 

 So, too, is every conclusion regarding the way in which non- 

 living things react upon one another, or living things perform 



