We all have heard that the Medieval view of grace was uber-realist – that infused grace is a substance that comes into the person. Peter Lombard held the opinion that this substance of grace was the Holy Spirit itself. Thomas Aquinas, while not preferring Lombard’s view, sought to demonstrate the gross errors of the former view.  Some, says Aquinas, believe that infused virtue cannot be increased because any added virtue would be new and different (ergo not “increased”) as any brick added to a wall must be a new brick.

Aquinas’s answer to this objection should be very appealing to the modern linguist.  He says that some are led into error by using “virtue” as a noun. As the Medieval interpreter of Aristotle would know, the science of metaphysics has very much to do with defining things.  Terms like substance, form, genus, species, etc. can be put into a syllogism.  These terms represent the way things are but also the way we think.  The subject and predicate correspond to substance and form.  For example “The ball is round” – “ball” represents substance and “round” represents form.  And because “round” is not a thing separate from the “ball” so one should not speak of “grace” or “virtue” as if it were some “thing” of which other “things” can be predicated. 

Aquinas addresses the following to those who think that infused virtues must be newly created by inpouring or that they are material elements: 

They do not notice that just as being belongs not to a form but to a subject by means of the form, so too the process of coming into being (which concludes with there being a form) does not belong to the form, but to the subject.  A form x is called a ‘being’ not because it itself is, if we speak strictly, but because something is it.  In the same way, a form is said to ‘come into being’ not because it itself come into being, but because something comes to be it: namely when its subject is brought from capacity to actualization. (Disputed Questions on the Virtues In General, a. 11)

In other words infused virtue does not exist by itself but “something is it.”  Jim is a faithful man, but Jim’s faith does not exist as part of or apart from Jim. But, others have objected, we speak of infused virtue “increasing.” Doesn’t this imply some sort of added thing? Aquinas, again tickling the penchant of the linguist, replies that we name things that are lesser known from the names of things that are better known.  For example, change of place is better understood than change from material corruption.  Therefore, we speak of a dead relative as having “passed away” or as “gone.” He continues:

In a similar way, since we perceive more easily when something changes its size than when it changes in the sense of altering in quality, it comes about that words suitable for change of size are used also in the context of altering in quality.  Now a body that changes its size until it is complete is said to increase, and the final, complete, size is called ‘big’ by comparison with the incomplete.  Similarly, then, for the reasons I have explained, something that changes in its quality from incomplete to complete is said to ‘increase’ in quality, and the complete quality is described as ‘big’ by comparison with the incomplete. Moreover, since the completeness of a thing is its goodness, Augustine says that even in things that are not big in terms of size, we still take ‘more’ to mean ‘better.’ (Ibid)

So, it is easier for us to speak of virtue “increasing” because the notion of something becoming bigger is just easier to understand than the actualization of a potential quality.  The word “increasing” is here used metaphorically or analogically.  Aquinas is therefore o.k. with speaking of virtue as if it were a substance because it is easier to understand it that way, but he stresses that we must not mistake the sign for the thing, we must recognize that we speak in metaphor.  

BUT, infused virtue is not the same as grace! This is true.  So, why have I been talking about virtue? Because, Aquinas raises the same objection to the infusion of grace in the Summa Theologiae and notes the same problem of “picture thinking” (as Lewis would say). Only, he does not go into as much detail concerning the nature of the problem as he does here, and both infused grace and infused virtue are qualities – neither should be spoken of in terms of quantity.  He speaks of the problem and the solution:

Every substance is either the nature of the thing whereof it is the substance, or is a part of the nature, even as matter and form are called substance.  And because grace is above human nature, it cannot be a substance or a substantial form, but is an accidental form of the soul.  Now what is substantially in God, becomes accidental in the soul participating in the Divine goodness, as is clear in the case of knowledge. (ST I-II, Q.110, a.4)

He also explains the difference between virtue and grace, the former being a disposition governed by the natural light of reason and the latter itself being the root and supernatural light of the virtues.  Grace is the principle whereas the virtues are the medium.  Both are infused and both are qualities that actualize a person’s nature.  Both are spoken of as substances but neither are substances.  Infused grace is a new quality caused by man’s “contact” with the Divine nature.  This opinion (that grace is not a substance) marks a break between Aquinas and the tradition of Peter Lombard and demonstrates a tendency of theological picture-thinking that did exist in the Medieval church. Unfortunately, this tendency did not go away with Aquinas’s clarification and continues to prevail today even among Reformed Protestants.