314 



FALLACIES, 



superstitions as these last must be the result of study ; they 

 are too recondite for natural or spontaneous growth. But 

 when the attempt was once made to construct a science of 

 predictions, any association, though ever so faint or remote, 

 by which an object could be connected in however far-fetched 

 a manner with ideas either of prosperity or of danger and 

 misfortune, was enough to determine its being classed among 

 good or evil omens. 



An example of rather a different kind from any of these, 

 but falling under the same principle, is the famous attempt on 

 which so much labour and ingenuity were expended by the 

 alchemists, to make gold potable. The motive to this was a 

 conceit that potable gold could be no other than the universal 

 medicine : and why gold ? Because it was so precious. It 

 must have all marvellous properties as a physical substance, 

 because the mind was already accustomed to marvel at it. 



From a similar feeling, " every substance," says Dr. Paris,* 

 " whose origin is involved in mystery, has at different times 

 been eagerly applied to the purposes of medicine. Not long 

 since, one of those showers which are now known to consist 

 of the excrements of insects, fell in the north of Italy ; the 

 inhabitants regarded it as manna, or some supernatural 

 panacea, and they swallowed it with such avidity, that it was 

 only by extreme address that a small quantity was obtained 

 for a chemical examination." The superstition, in this in- 

 stance, though doubtless partly of a religious character, pro- 

 bably in part also arose from the prejudice that a wonderful 

 thing must of course have wonderful properties. 



3. The instances of a priori fallacy which we have 

 hitherto cited belong to the class of vulgar errors, and do 

 not now, nor in any but a rude age ever could, impose upon 

 minds of any considerable attainments. But those to which 

 we are about to proceed, have been, and still are, all but 

 universally prevalent among thinkers. The same disposition 



* Pharmacologia, Historical Introduction, p. 16. 



