To begin we must turn to Boethius. However, to turn here first is already to make an interpretative choice. On the one hand, Boethius’ influence on the later scholastic disputes on the question is unmistakable. On the other hand, there is no scholarly consensus over whether Boethius himself ever actually conceived of such a distinction between essence and existence. The center of the controversy is found in the second axiom laid down by Boethius in a small theological treatise, referred to in its abbreviated form as Quomodo substantiae. Here, Boethius writes: diversum est esse et id quod est, ‘‘‘being’ and the ‘that which is’ are diverse.’’ Evidently, Boethius believes something to be distinct, but determining just what the esse and the id quod est are has proved to be an extremely difficult task.
There are some who see Boethius as simply making an Aristotelian distinction between primary (id quod est) and secondary (esse) substances (see Nash-Marshall 2000:234). However, others think Boethius is going beyond Aristotle and identifying existence as a separate ontological component of every existing individual. Pierre Hadot, who pays particular attention to the NeoPlatonic influences of Boethius, argues that the distinction in Boethius is not between essence and a concrete instantiation. He insists, rather, that it is a distinction between the absolute act of existence and the individual being, which receives its own existence through its participation in the said act of existence (Hadot 1963). Granting this interpretation, we can see a real beginning to the essence-existence distinction. The essence of the id quod est cannot be said to be the cause of its existence. Rather, the id quod est is a composition between the absolute act of existence, ipsum esse, and the finite form that participates in that existence. By such participation, form limits and constricts the absolute existence to its finite character as it exists in the id quod est (see Nash-Marshall 2000:231).
In the end, the right interpretation of Boethius is less important to the history of this medieval discussion than what his medieval successors took away from Boethius. Here, they saw proof that an Aristotelian essence of a thing was not sufficient to account for its actuality. This essence required something else, namely, esse and the causal efficacy of a divine creator. Much of the subsequent controversy is a reoccurring consideration of precisely this issue: is essence sufficient for existence, and, if not, what else is needed, where does it come from, and how is it related to its essence?
In addition to the early influence of Boethius on later scholastics, the work of Avicenna must also be recognized. While Boethius’ contribution focuses primarily on the notion of the absolute activity of esse and the insufficiency of an essence to explain existence, later scholastic thinkers generally looked to Avicenna to find a strong notion of a thing’s essence as having a kind of reality in its own right, distinct from its concrete existence. This is particularly noteworthy, given that it remains controversial whether this emphasis on essence actually distorts Avicenna’s position. Some scholars continue to argue that, in the end, existence is the true primary concept for Avicenna (e. g., Druart 2006:337).
The locus classicus of this distinction, as Avicenna describes it, is found in his Metaphysics of the Healing, Book I, chap. 5. It is here that he makes a famous distinction between what he calls the ‘‘existent’’ and the ‘‘thing.’’ The former, for Avicenna, is the concrete existing thing replete with all the attributes and accidental predications that come with being a part ofthe actual world. The latter - the ‘‘thing’’ - is that which has a nature that makes it what it is (I.5.9). This nature of a ‘‘thing’’ is the true and Essential core of any particular existent. Now, somewhat surprisingly, the term existence can be predicated of both the ‘‘existent’’ and the ‘‘thing.’’ The ‘‘thing,’’ Avicenna says, can be signified by the term existence, but only to signify, what he calls, the proper existence of some entity. But existence can also signify the affirmative existence of an entity. While the former sense of existence indicates the ‘‘whatness’’ of any reality stripped of every concomitant feature, the latter is meant to signify something beyond the mere essence of a ‘‘thing,’’ namely, that the ‘‘thing’’ is.
For Avicenna, that a kind of existence is predicated of a ‘‘thing’’ and its essence is not necessarily an indication that he thinks an essence somehow has its own separate ontological status and then is subsequently composed with a further existence. On the contrary, it is more likely that this is his way ofindicating that the same entity can be looked at from different perspectives. We can, on the one hand, consider something as an extra-mental reality partaking of all its accidental properties. From this vantage point, we are emphasizing its affirmative existence and its status as an existent. But we can also see the same reality stripped of its accidental characteristics including its extra - or even intra-mental existence. Here, we are attentive to the essential core of what exists, and thus we are attentive to its proper existence as a ‘‘thing.’’ (See the entry on Avicenna, sect. 3.)
With this said, it is important to recognize that scholastic commentators have not always read Avicenna this way. In fact, many contemporary scholars have been working hard to combat precisely the reading given by these later scholastic interpreters (e. g., Rahman 1958, 1981). Henry of Ghent, for one, points to a certain text in Book V of Avicenna’s Metaphysics as the source of his understanding of the ‘‘being of essence’’ or esse essentiae (Henry of Ghent, Quodlibet 1, q. 9). With this phrase - which would quickly enter into scholastic parlance generally - he meant to attribute a kind of independent existence to an essence prior to its status as actually existing. In Book V, cited by Henry, Avicenna does give explicit attention to the proper existence as distinct from its affirmative existence. Here, Avicenna is at pains to identify the whatness or essence of any reality, stripped of all concomitant and extraneous features. In considering animality, he notes that even though, inasmuch as it exists, it ‘‘exists with another,’’ its proper existence remains distinct. Any additional element, such as its actual or affirmative existence, whether in the mind or extra-mental reality, should be seen as an addition that ‘‘occurs to it’’ (V.1.18 trans. Marmura 2005:153). To the minds of his scholastic readers, this phrase, ‘‘occurs to it,’’ suggests that the ‘‘thing’’ with its proper existence need not be seen as dependent on the mind or some concrete instantiation for its meaning and reality. Concern will often be raised about the somewhat ambiguous ontological status of the being of an essence independent of its actual existence. Suarez, for one, will point to this as a fatal ambiguity that mars the discussion of essence and existence from this point forward (see Wells 1962:437, 444). Despite these ambiguities and possible concerns, Avicenna remains extremely important. It is from these influential passages that Aquinas and all of the major thinkers in the thirteenth century will take their starting point.
World History
