SCIENTIFIC METHOD 49 



these he regarded as the direct work of the devil and 

 as evidence of his presence in our midst. The treatise 

 is entitled The Vanity of Dogmatising or Confidence in 

 Opinions, manifested in a discourse of the shortness and 

 uncertainty of our knowledge and its causes. It sets forth 

 the various defects in man's body and mind, which were, 

 in his opinion, the necessary consequence of Adam's sin 

 and the Fall. All mankind after the expulsion from 

 Eden thus bears the mark of the serpent, and this is 

 particularly shown by predisposition to error. Among 

 the sources of error upon which he lays stress are, 

 first, the circumstance that our mental powers are 

 limited in as much as we can perceive nothing but by 

 proportion to our senses, and, secondly, the misleading 

 and erroneous character of the knowledge we thus 

 obtain. By a number of apt illustrations he displays 

 ' the imposture and fallacy of our senses which impose 

 not only on common Heads, who scarce at all live to the 

 higher principle, but even more refined Mercuries who, 

 having the advantage of an improved reason to disabuse 

 them, are yet frequently captivated by these deceiving 

 Prepossessions.' Glanville instances as a ' sensitive 

 deception ' the quiescence of the earth. ' Sense,' he 

 says, ' is the great inducement to its belief; its testimony 

 deserves no credit in this case, though it do move, sense 

 would present it as immovable.' This and other ' deceiv- 

 ing prepossessions ' are ' in propriety of speech not due 

 to the senses themselves being deceived, the senses only 

 administer an occasion of deceit to the understanding.' 



Modern physiology has revealed the complex source 

 of erroneous sensory perceptions, which have their origin, 

 not only in the delusive character of the mental mould 

 causing an error of sensory judgement, but also in the 

 imperfections of the sensory recipient organs; both the 



