THE SIGNIFICANCE OF THE UNIVERSAL 



UT NUNC 



(TfO 



IN his commentary on the Posterior Analytics of Aristotle, 

 St. Thomas notes that did de omni, sometimes translated 

 as " true in every instance," is treated differently in the 

 Posterior Analytics from the way it is in the Prior Analytics. 

 In the latter work, which is concerned with the form of the syllo- 

 gism and therefore with what is common to any syllogism, did 

 de omni is treated only commonly, disregarding the differences 

 attaching to a demonstrative or dialectical use. In this context, 

 it is enough to say that did de omni is realized whenever the 

 predicate is found to be in each of those things which are con- 

 tained under the subject. Once, however, we begin to consider 

 the syllogism on the part of matter, we must say more about 

 did de omni. Hence, immediately after saying that the predi- 

 cate is found in each of those things which are contained under 

 the subject, St. Thomas adds: " This can happen either ut nunc, 

 and in this way the dialectician sometimes uses did de omni, 

 or absolutely and for all time, and in this way only the demon- 

 strator uses it." ^ 



In discussing the ancient and medieval theory of universals, 

 we are apt to overlook this distinction between the verified did 

 de omni and the provisional one called universal ut nunc, and 

 we tend to ignore the importance the latter has as a tool 

 particularly for the investigation of nature. An example of the 

 verified did de omni was the common property of every para- 

 bolic triangle, ' to have its three angles equal to two right 

 angles.' An instance of the universal ut nunc was ' white ' 

 predicated as a common property of swans. The former 

 property was based upon a propter quid demonstration; the 

 latter was based upon, or rather derived from, an incomplete 



^ " Hoc autem contingit vel ut nunc, et sic utitur quandoque did de omni dia- 

 lecticus; vel dmpliciter et secundum omne tempus, et sic solum utitur eo demon- 

 strator." In I Post. Anal., lect. 9, n. 4. 



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