Entry 0389: Commentary on De veritate, question 1, article 1
In De veritate, question 1, article 1, Aquinas explicitly uses the expression actus essendi five times: once in the corpus, once in the response to the first objection, and three times in the response to the third argument in the sed contra. In this post I shall comment on the context surrounding the text presented in the corpus.
The first article of De veritate deals with the question “What is truth?” but the article contains what has been called “the most systematic derivation” of the transcendental notions written in the thirteenth century. (See Jan A. Aertsen, “Thomas Aquinas: A First Model,” in Medieval Philosophy as Transcendental thought: From Philip the Chancellor (ca. 1225) to Francisco Suárez [
E. J. Brill, 2012], 211. For a more thorough analysis of the text of De veritate, question 1, article 1, see also
J. A. Aertsen, Medieval Philosophy and the Transcendentals: The Case of
Thomas Aquinas [Leiden: E. J. Brill, 1996], chapter 2.)
The expression actus essendi appears in the first part of the article as Aquinas explains that the inquiry into what something is, requires antecedent knowledge. In conducting such inquiry, Aquinas affirms, previous knowledge should not be extended into an infinite regress for that would render the formation of concepts impossible. Thus the beginning of human thought, Aquinas postulates, is a primary notion which the human intellect conceives immediately. This is the notion of ens. No other previously known notion is needed for the human intellect to conceive ens, for ens is that which the intellect conceives first and quasi notissimum from the information supplied by sensible experience. Ens is not only the first notion in concept formation, ens is also the first among the other primary notions for the notion of ens is included in the understanding of any other notion.
Having established the absolute priority of the notion of ens, Aquinas proceeds to explain that all intellectual activity consists in adding something to the always present primary intellectual conception of ens. This addition, however, is unique in the sense that anything that in any way whatsoever is proposed to be added to ens is already ens, and, so, nothing can really be added to ens in the way species are added to a genus or accidents to a subject. The species of man, for example, adds to animal the connotation of rational which the genus animal does not possess. But nothing can be added in this way to ens, for under the notion of ens, all animals are ens, all men are ens, and all things are ens. This is the reason why ens is not a genus. Addition is then said to be applicable to the notion of ens when what is added expresses a modus entis that the word ens does not express. And here Aquinas distinguishes between (a) added expressions that refer to a special modus entis and (b) added expressions that refer to a general modus entis.
In the special modus entis Aquinas places the categories of substance and accidents, none of which add to ens anything that can be considered an addition of a species added to a genus. What the categories of substance and accidents add to the notion of ens is that they express a special modus essendi, like ens per se in the case of substance.
In the general modus entis Aquinas further distinguishes between (a) added expressions that refer to ens considered in itself and (b) added expressions that refer to ens in what regards the relation of one ens to another. In the first of these sub-groups, Aquinas lists the added expressions of res and unum. The second sub-group includes the added expressions of aliquid, bonum, and verum.
It is in his explanation of how the word res expresses something that the notion of ens does not express that Aquinas introduces the term actus essendi in the present article. In every ens, he says, one finds an essence as the recipient of esse. But essence is that from which the name res is imposed. Thus, following Avicenna Aquinas contends that the difference between ens and res is this, that the name ens is taken from the actus essendi, while the name res expresses the essence or quiddity of the thing.
Thus Aquinas writes:
“Sicut in demonstrabilibus oportet fieri reductionem in aliqua principia per se intellectui nota, ita investigando quid est unumquodque; alias utrobique in infinitum iretur, et sic periret omnino scientia et cognitio rerum. Illud autem quod primo intellectus concipit quasi notissimum, et in quod conceptiones omnes resolvit, est ens, ut Avicenna dicit in principio suae Metaphysicae. Unde oportet quod omnes aliae conceptiones intellectus accipiantur ex additione ad ens. Sed enti non possunt addi aliqua quasi extranea per modum quo differentia additur generi, vel accidens subiecto, quia quaelibet natura est essentialiter ens; unde probat etiam Philosophus in III Metaphys., quod ens non potest esse genus, sed secundum hoc aliqua dicuntur addere super ens, in quantum exprimunt modum ipsius entis qui nomine entis non exprimitur. Quod dupliciter contingit: uno modo ut modus expressus sit aliquis specialis modus entis. Sunt enim diversi gradus entitatis, secundum quos accipiuntur diversi modi essendi, et iuxta hos modos accipiuntur diversa rerum genera. Substantia enim non addit super ens aliquam differentiam, quae designet aliquam naturam superadditam enti, sed nomine substantiae exprimitur specialis quidam modus essendi, scilicet per se ens; et ita est in aliis generibus. Alio modo ita quod modus expressus sit modus generalis consequens omne ens; et hic modus dupliciter accipi potest: uno modo secundum quod consequitur unumquodque ens in se; alio modo secundum quod consequitur unum ens in ordine ad aliud. Si primo modo, hoc est dupliciter quia vel exprimitur in ente aliquid affirmative vel negative. Non autem invenitur aliquid affirmative dictum absolute quod possit accipi in omni ente, nisi essentia eius, secundum quam esse dicitur; et sic imponitur hoc nomen res, quod in hoc differt ab ente, secundum Avicennam in principio Metaphys., quod ens sumitur ab actu essendi, sed nomen rei exprimit quidditatem vel essentiam entis” (De veritate, question 1, article 1, corpus).
For our purposes here it is important to observe that in this text Aquinas is establishing a connection between the beginning of knowledge and the ratio significata of the term ens which is the notion of actus essendi: (a) Illud in quod intellectus conceptiones omnes resolvit est ens, and (b) ens sumitur ab actu essendi.