162 INTRODUCTION. 



By this he plainly tells us that no one can truly be enti- 

 tled discreet or well-informed, who does not of his own expe- 

 rience, i. e. from repeated memory, frequent perception by sense, 

 and diligent observation, know that a thing is so in fact. 

 Without these, indeed, we only imagine or believe, and such 

 knowledge is rather to be accounted as belonging to others than 

 to us. The method of investigating truth commonly pursued 

 at this time therefore is to be held as erroneous and almost 

 foolish, in which so many inquire what others have said, and 

 omit to ask whether the things themselves be actually so or 

 not; and single universal conclusions being deduced from several 

 premises, and analogies being thence shaped out, we have fre- 

 quently mere verisimilitudes handed down to us instead of 

 positive truths. Whence it comes that pretenders to know- 

 ledge and sophists, trimming up the discoveries of others, 

 changing the arrangement only, or the language, and adding 

 a few things of no importance, audaciously send them forth as 

 their own, and so render philosophy, which ought to be certain 

 and perspicuous, obscure and intricate. For he who reads the 

 words of an author and fails, through his own senses, to obtain 

 images of the things that are conveyed in these words, derives 

 not true ideas, but false fancies and empty visions ; whence 

 he conjures up shadows and chimeras, and his whole theory or 

 contemplation, which, however, he regards as knowledge, is 

 nothing more than a waking dream, or such a delirium as the 

 sick fancy engenders. 



I therefore whisper in your ear, friendly reader, and recom- 

 mend you to weigh carefully in the balance of exact expe- 

 rience all that I shall deliver in these Exercises on the Gene- 

 ration of Animals ; I would not that you gave credit to aught 

 they contain save in so far as you find it confirmed and borne 

 out by the unquestionable testimony of your own senses. 



The same course is even advised by Aristotle, who, after 

 having gone over a great many particulars about bees, says at 



