PROGRESS OF THE ARTS. 241 



those powers of practical observation and practical skill were at work, 

 which prepare the way for theoretical views and scientific discoveries. 



It may be urged, that the great works of art do virtually take for 

 granted principles of science ; and that, therefore, it is unreasonable to 

 deny science to great artists. It may be said, that the grand structures 

 of Cologne, or Amiens, or Canterbury, could not have been erected 

 without a profound knowledge of mechanical principles. 



To this we reply, that such knowledge is manifestly not of the nature 

 of that which we call science. If the beautiful and skilful structures 

 of the middle ages prove that mechanics then existed as a science, 

 mechanics must have existed as a science also amono- the builders of 

 the Cyclopean walls of Greece and Italy, or of our own Stonehenge, - 

 for the masses which are there piled on each other, could not be raised 

 without considerable mechanical skill. But we may go much further. 

 The actions of every man who raises and balances weights, or walks 

 along a pole, take for granted the laws of equilibrium; and even 

 animals constantly avail themselves of such principles. Are these, 

 then, acquainted with mechanics as a science ? Again, if actions 

 which are performed by taking advantage of mechanical properties 

 prove a knowledge of the science of mechanics, they must also be 

 allowed to prove a knowledge of the science of geometry, when they 

 proceed on geometrical properties. But the most familiar actions of 

 men and animals proceed upon geometrical truths. The Epicureans 

 held, as Proclus informs us, that even asses knew that two sides of a 

 triangle are greater than the third. And animals may truly be said 

 to have a practical knowledge of this truth ; but they have not, there- 

 fore, a science of geometry. And in like manner among men, if we 

 consider the matter strictly, a practical assumption of a principle does 

 not imply a speculative knowledge of it. 



We may, in another way also, show how inadmissible are the works 

 of the Master Artists of the middle a^es into the series of events which 

 mark the advance of Science. The following maxim is applicable to 

 a history, such as we are here endeavoring to write. We are employed 

 in tracing the progress of such general principles as constitute each of 

 the sciences which we are reviewing ; and no facts or subordinate 

 truths belong to our scheme, except so far as they lead to or are 

 included in these higher principles; nor are they important to us, any 

 further than as they prove such principles. Now with regard to pro- 

 cesses of art like those which we have referred to, namely, the inven- 

 tions of the middle ages, let us ask, what principle each of them 

 Vol. L— 16 



