ORDER IN THE PHILOSOPHY OF NATURE 267 



To ignore these will severely blemish the science achieved and 

 particularly the teaching of that science. 



It will be profitable, therefore, to make a synthetic study of 

 the principles of order governing the philosophy of nature. 



Two texts of St. Thomas can serve to introduce the question. 



The concept of order includes three elements: first, the idea of 

 before and after; hence there is order in all those ways by which 

 one thing can be before another, by place, time, and so forth. 

 Order also includes distinction, because only distinct things have 

 any order. But this is rather presupposed than signified by the 

 word " order." The third element is a principle of order, according 

 to which order is divided into its species. Hence there is an order 

 according to place, another according to dignity, and another 

 according to origin.* 



Succession, distinction, and a principle of order: all these 

 are pertinent to the consideration of order in the philosophy 

 of nature. St. Thomas elaborates on the principle of order in 

 the second text: 



Order always has reference to some principle. Therefore, since 

 there are many kinds of principle — namely, according to site, as a 

 point; according to intellect, as the principle of demonstration; 

 and according to each individual cause — so there are many kinds 

 of order.^ 



It is the order according to intellect that mainly interests us, 

 because we are here considering the problem of ordering a 

 science. The principle of that order will in some way coincide 

 with " the principle of demonstration." Since demonstration 

 is the means for achieving scientific knowledge, the order within 



* " Ordo in ratione sua includit tria, scil. rationem prioris et posterioris; unde 

 secundum omnes illos modos potest dici esse ordo aliquorum, secundum quos aliquis 

 altero prius dicitur et secundum locum et secundum tempus et secundum omnia 

 huiusmodi. Includit etiam distinctionem, quia non est ordo aliquorum nisi distinc- 

 torum. Sed hoc magis praesupponit nomen ordinis, quam significet. Includit etiam 

 tertio rationem ordinis, ex qua etiam ordo in speciem contrahitur. Unde unus est 

 ordo secundum locum, alius secundum dignitatem, alius secundum originem " 

 (Super Libros Sententiarum, I, d. 20, 3, 1. Cf. Summa Theol., II-II, 26, 1). 



° Summa Theol., I, 42, 3, transl. A. Pegis, Basic Writings of Saint Thomas Aquinas 

 (New York: Random House, 1945). 



