INDUCTION OF COPERNICUS. 393 



difference. Copernicus erroneously supposes the 

 precession to be unequable ; and his method of 

 explaining this change, which is simpler than that 

 of the ancients, becomes more simple still, when 

 applied to the true state of the facts. 



The tendencies of our speculative nature, which 

 carry us onwards in pursuit of symmetry and rule, 

 and which thus produced the theory of Copernicus, 

 as they produce all theories, perpetually show their 

 vigour by overshooting their mark. They obtain 

 something by aiming at much more. They detect 

 the order and connexion which exist, by imagining 

 relations of order and connexion which have no 

 existence. Real discoveries are thus mixed with 

 baseless assumptions; profound sagacity is com- 

 bined with fanciful conjecture ; not rarely, or in pe- 

 culiar instances, but commonly, and in most cases ; 

 probably in all, if we could read the thoughts of 

 the discoverers as we read the books of Kepler. 

 To try wrong guesses is apparently the only way to 

 hit upon right ones. The character of the true 

 philosopher is, not that he never conjectures hazard- 

 ously, but that his conjectures are clearly conceived 

 and brought into rigid contact with facts. He sees 

 and compares distinctly the ideas and the things, 

 the relations of his notions to each other and to 

 phenomena. Under these conditions it is not only 

 excusable, but necessary for him, to snatch at every 

 semblance of general rule; to try all promising 

 forms of simplicity and symmetry. 



