186 SCIENCE REMAKING THE WORLD 



(3) The scientific spirit keeps one close to the facts. 

 One of the hardest things in my teaching experience 

 has been to check the tendency of many students to use 

 one fact as a starting point for a flight of fancy that 

 is simply prodigious. Such a tendency is corrected, of 

 course, when the facts accumulate somewhat, and flight 

 in one direction is checked by a pull in some other di- 

 rection; but most of us have this tendency, and the 

 majority are so unhampered by facts that flight is free. 

 This exercise is beautiful and invigorating if it is recog- 

 nized to be what it really is, a flight of fancy; but if 

 it results in a system of belief it is a deception. 



There seems to be abroad a notion that one may start 

 with a single, well-attested fact, and by some logical 

 machinery construct an elaborate system and reach an 

 authentic conclusion; much as the world has imagined 

 for more than a century that Cuvier could do if a single 

 bone were furnished him. The result is bad, even 

 though the fact have an unclouded title; but it too often 

 happens that great superstructures have been reared on 

 a fact which is claimed rather than demonstrated. 



We are not called upon to construct a theory of the 

 universe upon every well-attested fact, and the sooner 

 this is learned the more time will be saved and the 

 more functional will the observing powers remain. 

 Facts are like stepping stones; so long as one can get a 

 reasonably close series of them, he can make progress in 

 a given direction; but when he steps beyond them he 

 flounders. As one travels away from a fact, its signi- 

 ficance in any conclusion becomes more and more at- 

 tenuated, until presently the vanishing point is reached, 



