Boethius

In his second greater commentary on Porphyry’s Isagoge, Boethius developed a series of intriguing arguments in favor of the conclusion that universals do not exist outside the mind (In Isag. 2nd ed., 1,10-11,159-167, [trans. Spade 1994:21-23]; cf. Spade 1996). The main thrust of these arguments was that something exists outside the mind only if it is a unity; yet, it is impossible for something to be one and also wholly present in each of its instantiations in such a manner that it contributes to each individual’s substance. Hence, universals cannot subsist.

Boethius, then, posed a dilemma for the anti-realist, who believes that universals do not exist outside the mind. We surely have concepts that are universal. In particular, we believe that the concept human applies to Adam and Eve and that this is true because Adam and Eve are naturally similar to one another and to all other humans. But if Adam and Eve have no thing in common, then these attributions and classifications do not represent the world as it truly is. In short, if there are no universal things, then our concepts appear to be empty and false.

Boethius offered a solution that he attributed to the third-century Aristotelian philosopher Alexander of Aphrodisias. The mind is capable of considering things in a manner different from that in which they exist. In particular, the mind is able to consider and compare the features of concrete particulars without reference to the particular, even though these features cannot actually be separated from the particulars. By abstracting features in this manner, the mind is able to construct universal concepts. Hence, while universals do not exist in things as something common to many, the concept of a universal - since it is abstracted from things in the right way - can be truthfully attributed to many things. It is not clear that Boethius’ Alexandrian solution resolved his aporia, for it is unclear what the mind abstracts from individuals. Nevertheless, the notion that the mind contributed universality to whatever it is that is abstracted from many individuals would be very popular in succeeding generations.