Dh WHEWELL, ON PLATO'S SURVEY OF THE SCIENCES. 



583 



exceptions, philosophy in them is extinguished : extinguished far more completely than the 

 Heraclitean sun, for theirs is not lighted up again, as that is every morning:" alluding to the 

 opinion which was propounded, by way of carrying the doctrine of the unfixity of sensible 

 objects to an extreme ; that the Sun is extinguished every night and lighted again in the 

 morning. In opposition to this practice, Plato holds that philosophy should be the especial 

 employment of men's minds when their bodily strength fails. 



What Plato means by Dialectic, which he, in the next Book, calls the highest part of 

 philosophy, and which is, I think, what he here means by the hardest part of philosophy, I 

 may hereafter consider : but at present I wish to pass in review the Sciences which he speaks 

 of, as leading the way to that highest study. These Sciences are Arithmetic, Plane Geometry, 

 Solid Geometry, Astronomy and Harmonics. 



The view in which Plato here regards the Sciences is, as the instruments of that culture 

 of the philosophical spirit which is to make the philosopher the fit and natural ruler of the 

 perfect State — the Platonic Polity. It is held that to answer this purpose, the mind must 

 be instructed in something more stable than the knowledge supplied by the senses ; — a know- 

 ledge of objects which are constantly changing, and which therefore can be no real permanent 

 Knowledge, but only Opinion. The real and permanent Knowledge which we thus require is 

 to be found in certain sciences, which deal with truths necessary and universal, as we should 

 now describe them: and which therefore are, in Plato's language, a knowledge of that 

 which really is*. 



This is the object of the Sciences of which Plato speaks. And hence, when he introduces 

 Arithmetic, as the first of the Sciences which are to be employed in this mental discipline, he 

 adds (vn. & 8) that it must be not mere common Arithmetic, but a science which leads to 

 speculative truthsj-, seen by Intuition j; not an Arithmetic which is studied for the sake of 

 buying and selling, as among tradesmen and shopkeepers, but for the sake of pure and real 

 Science §. 



I shall not dwell upon the details with which he illustrates this view, but proceed to the 

 other Sciences which he mentions. 



Geometry is then spoken of, as obviously the next Science in order; and it is asserted 

 that it really does answer the required condition of drawing the mind from visible, mutable 

 phenomena to a permanent reality. Geometers indeed speak of their visible diagrams, as if 

 their problems were certain practical processes ; to erect a perpendicular ; to construct a square : 

 and the like. But this language, though necessary, is really absurd. The figures are mere 

 aids to their reasonings. Their knowledge is really a knowledge not of visible objects, but of 

 permanent realities : and thus, Geometry is one of the helps by which the mind may be drawn 

 to Truth ; by which the philosophical spirit may be formed, which looks upwards instead of 

 downwards. 



Astronomy is suggested as the Science next in order, but Socrates, the leader of the 

 dialogue, remarks that there is an intermediate Science first to be considered. Geometry, 



* The sciences are to draw the mind from that which grows 

 and perishes to that which really is : /idd^fxa </™x'7« o\k6v 

 dlro tov yiyvoflivov eirl to &v. 



•\~ eiri deal/ tiTs tW dpidfxujv tyvaews. 



\ TJJ voijtret avTg. 



Vol. IX. Part IV. 



§ He adds "and for the sake of war;" this point I have 

 passed by. Plato does not really ascribe much weight to this 

 use of Science, as we see in what he says of Geometry and 

 Astronomy. 



75 



