PREFACE. 



THEY who have presumed to dogmatise on Nature, as on 

 some well investigated subject, either from self-conceit or 

 arrogance, and in the professorial style, have inflicted the 

 greatest inj ury on philosophy and learning. For they have 

 tended to stifle and interrupt inquiry exactly in proportion 

 as they have prevailed in bringing others to their opinion : 

 and their own activity has not counterbalanced the mis 

 chief they have occasioned by corrupting and destroying 

 that of others. They again who have entered upon a con 

 trary course, and asserted that nothing whatever can be 

 known, whether they have fallen into this opinion from 

 their hatred of the ancient sophists, or from the hesitation 

 of their minds, or from an exuberance of learning, have 

 certainly adduced reasons for it which are by no means 

 contemptible. They have not, however, derived their opi 

 nion from true sources, and hurried on by their zeal, and 

 some affectation, have certainly exceeded due moderation. 

 But the more ancient Greeks (whose writings have perished) 

 held a more prudent mean, between the arrogance of dog 

 matism, and the despair of scepticism; and though too 

 frequently intermingling complaints and indignation at the 

 difficulty of inquiry, and the obscurity of things, and 

 champing, as it were, the bit, have still persisted in pres 

 sing their point, and pursuing their intercourse with nature : 

 thinking, as it seems, that the better method was not to 

 dispute upon the very point of the possibility of any thing 

 being known, but to put it to the test of experience. Yet 

 they themselves, by only employing the power of the un 

 derstanding, have not adopted a fixed rule, but have laid 

 their whole stress upon intense meditation, and a continual 

 exercise and perpetual agitation of the mind. 



Our method, though difficult in its operation, is easily 

 explained. It consists in determining the degrees of cer 

 tainty, whilst we, as it were, restore the senses to their 

 former rank, but generally reject that operation of the mind 

 which follows close upon the senses, and open and establish 

 a new and certain course for the mind from the first actual 



