FALLACIES OF SIMPLE INSPECTION. 381 



being of a red colour, portended fire and slaughter: and 

 the like. 



Passing from physics to metaphysics, we may 

 notice among the most remarkable fruits of this 

 a priori fallacy, two closely analogous theories, em- 

 ployed in ancient and in modern times to bridge over 

 the chasm between the world of mind and that of 

 matter: the species sensibiles of the Epicureans, and 

 the modern doctrine of perception by means of ideas. 

 These theories are indeed, probably, indebted for their 

 existence not solely to the fallacy in question, but to 

 that fallacy combined with another natural prejudice 

 already adverted to, that a thing cannot act where it is 

 not. In both doctrines it is assumed that the pheno- 

 menon which takes place in us when we see or touch 

 an object, and which we regard as an effect of that 

 object, or rather of its presence to our organs, must of 

 necessity resemble very closely the outward object 

 itself. To fulfil this condition, the Epicureans sup- 

 posed that objects were constantly projecting in all 

 directions impalpable images of themselves, which 

 entered at the eyes and penetrated to the mind: while 

 modern philosophers, though they rejected this hypo- 

 thesis, agreed in deeming it necessary to suppose 

 that not the object itself, but a mental image or 

 representation of it, was the direct object of percep- 

 tion. Dr. Reid had to employ a world of argument 

 and illustration to familiarize people with the truth, 

 that the sensations or impressions on our minds need 

 not necessarily be copies of, or have any resemblance 

 to, the causes which produce them ; in opposition to 

 the natural prejudice which led men to assimilate the 

 action of bodies upon our senses, and through them 

 upon our minds, to the transfer of a given form from 

 one object to another by actual moulding. The works 



