xvin PREFACE TO THE 



as those to which we owe the clearest and surest 

 portions of our knowledge. Such a renovation and 

 extension of the reform of philosophy appears to 

 belong peculiarly to our own time. We may discern 

 no few or doubtful presages of its approach ; and an 

 attempt to give form and connexion to the elements 

 of such a scheme cannot now be considered pre- 

 mature. 



The Novum Organon of Bacon was suitably 

 ushered into the world by his Advancement of Learn- 

 ing ; and any attempt to continue and extend his 

 Keform of the Methods and Philosophy of Science 

 may, like his, be most fitly preceded by, and founded 

 upon, a comprehensive Survey of the existing state 

 of human knowledge. The wish to contribute some- 

 thing, however little it may be, to such a Eeform, 

 gave rise to that study of the History of Science of 

 which the present Work is the fruit. And the effect 

 of these researches has been, a persuasion, that we 

 need not despair of seeing, even in our own time, 

 a renovation of sound philosophy, directed by the 

 light which the History of Science sheds. Such a 

 reform, when its Epoch shall arrive, will not be the 

 work of any single writer, but the result of the intel- 

 lectual tendencies of the age. He who is most for- 

 ward in the work will wisely repeat the confession 

 of his sagacious predecessor : Ipse certe (ut ingenue 

 fatear) soleo sBstimare hoc opus magis pro partu Tem- 

 poris quam Ingenii. 



To such a work, whensoever and by whomsoever 

 executed, I venture to hope that the present Volumes 

 may be usefully subservient. But I trust, also, that 



