The sharp distinction between essential and accidental attributes make possible a clear statement of the problem of universals. For universals, whose reality was the subject of speculation, are nothing but the genera and species - for example, “animal” and “man” — which are essential attributes of an individual like Socrates.
This notion was first clearly stated by Aristotle, although it was doubtless present earlier, and it was refined to its most precise and modern form during the Middle Ages. Aristotle dealt with this topic in several of his books, including one called Categories:
the Categories, the study of attributes, cannot refer to things (since res non praedicatur) but only to words as signifiers of things. Hence the solution, imbued with the spirit of Aristotle, of the problem of universals: genus and species exist only by virtue of predicates essential to the individual. “Individuals, species, and genus are one and the same reality (eadem res), and universals are not, as is sometimes stated, something different from universals.”
By the phrase res non praedicatur, we note that things are not predicates, and predicates are not things. If we say that “the car is old,” then “old” is a predicate, and therefore there is no thing which is “oldness” - “old” only exists in old things, but it does not exist by itself.
genus is to species and species is to the individual as matter is to form.
The debates about universals and nominalism become more interesting in special cases, like identity: why am I still me, even though everything about me might change? Also interesting are spiritual cases: how can bread and wine be transformed into body and blood? Such questions are located in a territory which is shared by philosophy and religion. Thinkers who deal with these questions see themselves as both philosophical and religious: Berengar of Tours, for example, agreed
that the Eucharist was a sacrament in the sense in which the word is used by Augustine: a sacred sign that takes us beyond the sensible appearance to an intelligible reality.
The sacraments have been repeatedly analyzed by philosophers, with many different understandings and interpretations of what their true nature is: in any case, they are not merely symbolic in the usual sense. As with physics at the micro and macro levels - subatomic and astro - our intellect with regard to reality
is like our senses in comparison with intelligence or one sense in comparison with another, that is, unable to understand but forced to believe what it does not understand. It would hardly be possible to state in more radical manner the fundamental discontinuity of the mind.
Can we really understand what it means for time to slow down, as general relativity shows? We encounter the limits of human reason in such situations, and our language has developed certain mechanisms for talking about those situations. We risk falling into error if we either take our language in such situations to function as it does in other more normal cases, or if we confuse the ability to talk about these cases with the ability to understand them.
