Reading Aquinas On Evil: Is Evil an Entity? (Q. 1, Art. 1)

This is the beginning of a series reading through St. Thomas Aquinas’s work De Malo or “On Evil”.

I’ve interacted in a few posts with several arguments for atheism/naturalism, but have purposefully not yet ventured towards that infamous, so-called “problem of evil”. This is because the question of the relation between evil and the existence of God is massive, complex, and doesn’t fit neatly under the heading of one general “problem”. There are many different arguments and types of arguments which move from the reality of evil (or something which might be categorized under evil, such as pain, suffering, etc.) towards the improbability or even impossibility of the existence of God. Recognizing the immensity and complexity of the various issues involved, I’ve chosen not to delve into it yet, and am doing so now only by way of exposition of Aquinas’ own writings on the subject. There are several reasons for this. First is just that I think what Aquinas has to say is interesting and significant in its own right. Second is that starting this way, by reading and thinking through a single text, narrows the topic considerably, providing a nice pathway by which to broach discussing evil and God generally. Finally, any argument which attempts to appeal to “evil” without establishing a sufficient metaphysical foundation of evil first is just futile. The same, by the way, is true of any theistic arguments which appeal to moral obligation or values. It is simply impossible to take serious any attempt at an argument from evil which does not provide an ontological account of what evil is in the first place.

Before I begin, however, I should note that it is just not the central aim of Aquinas in the De Malo to take on the “problem of evil”, especially not any modern or contemporary versions thereof. Aquinas here is not engaging in a project of natural theology. Instead, he’s exploring a metaphysical and (to some extent) theological account of evil. And that, too, will be the primary focus of this present series. But, hopefully, doing so will provide groundwork for later on when we turn to consider evil and its possible implications in relation to natural theology.

One more introductory note on format: The De Malo, like the Summa, is divided into various Questions, each of which contains several articles. In each article, Aquinas first asks a specific question, then gives various “objections” to his own position, then presents his own position, and finally responds to each of the objections. I will not be relaying all of this in full or necessarily in order; instead, I will just be exploring different central ideas.

The first question St. Thomas considers is whether evil is an “entity” or not. The main objection to Aquinas’s negative answer is that “contrary things are things in nature, since we posit them in the same genus. But evil is contrary to good . . . Therefore evil is an entity” [1]. The discussion of the ontological status of evil in relation to Christian theology had been going on for centuries by this point, especially since St. Augustine. In fact, this question of evil’s ontological status was one of the turning points in Augustine’s whole conversion. Augustine’s problem was essentially this: God is Goodness Itself. Whatever God creates is good. If God created everything that exists, then everything that exists must be good; so whence evil? In other words, how can one reconcile the first two propositions with the actual existence of evil? Either God did not actually create everything that exists, or else evil does not exist. In his years caught up in Manichaeism, Augustine held to the former. In the process of his conversion to Christianity, he became convinced of the latter: namely, that evil does not actually exist as a positive entity or substance. This is the question to which Aquinas turns now, nearly a thousand years later. Indeed, in declaring his own position he begins by quoting St. Augustine in saying that “evil is not a nature, but that the lack of good took on this ascription [of evil]” [2]. He then gives his explanation:

“We speak of evil in two ways, just as we do of white. For when we speak of white in one way, we can understand the subject that is white. In the second way, we call white what is white as such, namely, the very accidental quality. And we can similarly understand evil in one way as the subject that is evil, and this subject is an entity. In the second way, we can understand evil itself, and evil so understood is the very privation of a particular good, not an entity” [3].

In attributing the term “evil” to things, we have one of two meanings, similar to attributing “white” or some other quality. In one sense, when we speak of “white” we mean that which is white, the subject which possesses the quality “whiteness” such as a white horse or white wall, that in which the quality whiteness inheres. In another sense, we speak of that quality “whiteness” itself, which cannot ever exist on its own without inhering in some actual subject, but which can be considered conceptually as abstracted from its actual subjects (i.e., you can think of whiteness alone as an idea in your mind, but it can never actually exist on its own outside of a mind). So, in the same way, suggests Aquinas, we can understand designation of things as evil (or even just “bad” generally). When we say something like “he is an evil man”, we might be referring to the man himself, who we are qualifying as “evil”, whatever that happens to mean. In this case, evil most definitely is an actually existing entity, because otherwise it would not be a real subject for us to refer to. In order for us to say that he is an evil man, “he” must be real. But if we are considering this appellation “evil” in itself, as a mere quality that is abstracted from all subjects and considered purely conceptually, then, Aquinas says, evil is not an actually existing entity, but rather is “the very privation” of some good, meaning a lack or absence thereof. In other words, if we point out a car and say “That is a bad car”, the car itself exists as an entity, and is really a bad car, a bad sort of entity that it is; but the “badness” about it is not an entity in itself, but rather is some lacking in the car as an entity — perhaps it has a bad motor, or its battery has died, etc. But the badness of the car can only be present because the car itself were present; if there were no car, there could be no actual thing that is the “badness” of the car. The badness of the car is only there, and is only bad, because the car itself is there, and is really defective in some way.

“And to prove this, we need to note that good is, properly speaking, something real insofar as it is desirable, for the Philosopher in the Ethics says those who said that good is what all things desire defined it best. But we call what is contrary to good evil. And so evil is necessarily what is contrary to the desirable as such. And what is contrary to the desirable as such cannot be an entity. And this is evident for three reasons” [4].

Good is “being” considered under the aspect of its “desirability”. If you recall, Aquinas holds to the scholastic doctrine of the “Transcendentals”, which posits that certain transcendental concepts such as being, goodness, truth, and unity are all equivalent (see post on this here). So all being is good (Augustine attributes this to all being having been created by God who is Goodness Itself), and all goodness is real. But goodness specifically is being considered in relation to how it is desired —  desired not in the sense of just a conscious human desire but in the deeper sense of innate, natural desires which all things have but only humans can actually “know” in the full sense. Goodness considered as such is the being or actuality that fulfills a nature, perfecting its proper ends (as he will go on to explain below). So the nature of an eye is to see, and sight is the being or actuality that fulfills the nature of the eye; so we say that sight is the “good” of an eye and hence that the eye “desires” sight as its natural perfective end. And so this explains Aquinas’s statement that “what is contrary to the desirable as such cannot be an entity”. What is desirable is the being that fulfills or perfects something; and what is contrary to this must be some sort of “non-being” that does the opposite of fulfill or perfect. (We could go further on this, specifically relating it to Aquinas’s understanding of the will. For Aquinas, the will must necessarily desire that which it believes to be good). He goes on to explain:

“First, it is evident because the desirable has the nature of an end, and the order of ends is just like the order of efficient causes. For the higher and more universal an efficient cause is, the more universal is also the end for the sake of which the efficient cause acts, since every efficient cause acts for the sake of an end and some good. And this is clearly evident in human affairs; for example, the administrator of a city strives for a particular good that is the welfare of the city, and the king, who is superior to the city administrator, strives for the universal good, namely, the security of the whole kingdom. But it is impossible to regress endlessly in a series of efficient causes, and we need to arrive at one first efficient cause that is the universal cause of being. Therefore, there also needs to be a universal good to which we trace back all goods. And this universal good can only be the very thing that is the first and universal efficient cause. This is so because, since the desirable moves desire, and the first cause of movement is necessarily itself unmoved, the first and universal efficient cause is necessarily itself the first and universal desirable thing, that is, the first and universal good, which produces all things because of the love of its very self. Therefore, as every real thing needs to come from the first and universal cause, so every reality in things needs to come from the first and universal good. And since what the first and universal cause of being causes is a particular being, what the first and universal good causes can only be a particular good. Therefore, everything that is a real thing needs to be a particular good and so, by reason of what exists, cannot be contrary to good. And so we conclude that evil as such is the privation of a particular good, a privation that is associated with a particular good, and not an entity” [5].

There’s a lot here that I won’t now be going into fully. Basically, what Aquinas is saying is that anything that exists, insofar as it is an existing thing, is good (a particular good), because it derives from the universal Good which is Goodness Itself (similar to what we mentioned from St. Augustine earlier). So any particular entity, qua entity, will by definition be a particular good. And evil is by definition the contrary of good, so evil cannot be an entity.

“Second, the same conclusion is evident from the fact that every real thing has an inclination and desire for something that befits itself. But everything that has the nature of being desirable has the nature of good. Therefore, every real thing has a conformity with some good, and evil as such is not in harmony with good but contrary to it. Therefore, evil is not an entity. And if evil were a real thing, it would neither desire anything nor be desired by anything, and so have no activity or movement, since nothing acts or moves except because of the desire of an end” [6].

This is the explanation I gave earlier about sight and the eyes. He also adds that, since everything desirable (in terms of natural desire) is by definition a good, then even if we were to conclude that evil is some existing entity, it could not have any activity or movement, because every activity and movement necessarily acts for and moves toward some end, which is a good. But even this is impossible, because, as Aquinas argues elsewhere, existing itself is a type of activity; so if an entity lacked all activity, it would lack existence, and hence would not be an actually existing entity. To reiterate, there could be some real entity in which evil inheres, i.e. an entity which has a real privation of good, but that evil/privation considered in itself cannot be an actually existing entity. This point, about existing being an activity, is related to Aquinas’s third reason:

“Third, the same conclusion is evident from the fact that existing itself chiefly has the nature of being desirable, and so we perceive that everything by nature desires to conserve its existing and avoids things destructive of its existing and resists them as far as possible. Therefore, existing itself, insofar as it is desirable, is good. Therefore, evil, which is universally contrary to good, is necessarily also contrary to existing. And what is contrary to existing cannot be an entity” [7].

Existing is the primary activity of a thing; and so existing (or remaining in existence) is the primary end which all beings seek (as a natural, perfective end). Consider, for example, that what we humans chiefly consider as the worst of evils is death, which is the destruction and cessation of our existence. Evil is by nature destructive of an existing thing, whether just one of its “outer” properties or its must fundamental activity, its very being itself. But since existing is the primary end of things, per what we said above about the good being the (naturally) desirable, existence is the primary good. And so evil, which is contrary and destructive of good, is also contrary and destructive of existence. But what is contrary to existence by definition cannot itself be existence; so evil cannot be an actually existing entity.

So Aquinas concludes:

“And so I say that evil is not an entity, but the subject that evil befalls is, since evil is only the privation of a particular good. For example, blindness itself is not an entity, but the subject that blindness befalls is” [8].

Since sight is the natural, perfective end of an eye, that which fulfills its function and is as such the “good” of the eye, blindness is the “evil” or “badness” of the eye. But “blindness” is not an actual thing in itself; it is the privation of a thing, namely of sight. Blindness is certainly real, but is not in itself an existing thing. The eye is an existing entity in itself, but blindness is just the absence of the “good” of the eye. We should point out, however, that even though evil is a type of “non-being” since it is the absence of some type of being, evil is not therefore identical to “non-being” simply. Evil is the absence of some being that should be there, not just the absence of being in itself. For example, we don’t say that books are bad because they lack sight; books should lack sight since they aren’t the types of things which have the function of sight. So the “non-being” of sight in a book doesn’t make it bad; but the “non-being” of sight in an eye does, because eyes are the types of things which should have sight.

Aquinas considers a total of twenty objections in this article, and I’ll examine a few of them here.

One objection has to do with coming to grips with the fact that evil is in some sense created. While Aquinas is only discussing it in relation to the present question of evil as an entity, it obviously has some implications for other questions we might ask further on, such as why God “allows” evil. The objection is:

“Every created thing is an entity. But evil is something created . . . Therefore, evil is an entity” [9].

Aquinas takes this question as specifically referring to God “creating” evil as a punishment for some wickedness, not evil in general (the objection cites a passage of scripture which refers to God “creating” evil). But the problem remains: if God created evil, then evil must be an entity, for anything created is an entity. Aquinas responds:

“We call something evil in two ways: in one way, absolutely; in the second way, in a particular respect. And we call what is evil as such evil absolutely, and this consists of something being deprived of a particular good that is required for its perfection. For example, sickness is evil for an animal because it deprives the animal of the balance of fluids that is required for the perfection of the animal’s existing. And we call evil in a particular respect what is not evil as such; rather, we call evil in a particular respect what befalls something because it is deprived of a good that is required for the perfection of something else, not one that is required for its own perfection. For example, fire is deprived of the form of water, which is required for the perfection of water, not of a form that is required for the perfection of fire. And so fire is evil for water, not evil as such. And the order of justice likewise has a connected privation of the particular good of one who sins, since the order of justice requires that the person who sins should be deprived of a good that the person desires. Therefore, the punishment itself is, absolutely speaking, good, although it is evil for the person . . . And so it is evident that Scripture says that God created evil, not because it is evil, but because it is good, absolutely speaking, and evil in a particular respect” [10].

Again, this is referring specifically to evil used by God as punishment for human wickedness. Evil as such, or evil considered absolutely, is, as we’ve said, the privation of some good; and hence is not an actually existing entity. But there’s another sense in which we can call something evil, and that is something that is an evil to something else. Evil absolutely is the privation of a good, or the privation of some form that a thing is naturally directed towards, that is proper and good for its nature to possess. For example, “sight” is a form that is proper and good for humans to have; but “having wings” is not. When a human lacks wings, we don’t say that he’s defective in an way; but if he lacks sight, we do, since sight is a natural perfection of human beings. As Aquinas says, fire lacks the form of water, but we don’t for that reason say that fire in itself is something evil; nor do we say that water is evil because it lacks the form of fire. Water possesses the form that is proper to its nature. If it lacked the form proper to its nature, then that would be the privation of a good and hence evil. But fire and water, even if they both contain all the forms/perfections proper to their nature, can be “evils” to other things, including to each other. For instance, if one were to poor water over a fire, water would suddenly become an evil in relation to that fire, because it works to deprive the fire of its natural forms. So in this case, water is an actually existing entity, but it is acting to deprive another entity of its proper good, and hence acts as an “evil” to that entity. Water thus might be said to be “evil”, but not absolutely; only in relation to something else. Evil absolutely, then, cannot be an entity. (He goes on to relate this to justice and punishment, but we’ll leave that for another time).

Another objection has to do with evil as a cause:

“Everything that corrupts acts. But evil as such corrupts . . . Therefore, evil as such acts. But nothing acts except insofar as it is an entity. Therefore, evil as such is an entity” [11].

We’ve already discussed how only what actually exists can act or have activity or move or cause anything. But we also have said that evil as privation of good is destructive of something — in other words, it corrupts it. Remember that we aren’t saying that evil isn’t real; it certainly is. We’re just arguing that evil has no positive existence of its own, as an actual entity. A cavity, for instance, isn’t an actual being on it’s own. It is literally a hole in a tooth, an “absence” of tooth that is bad for the tooth in which it inheres. But it also causes corruption and decay in the tooth. How can something that is not an entity act?

Some might reply that evil is not an activity but a lack of activity. So the next objection argues against this:

“People have said that corruption is due to lack of activity rather than activity. But corruption involves movement or change. Therefore, corruption causes change. But causing change is activity. Therefore, corruption is activity” [12].

Blindness, obviously, causes change in the eye (in the case of people who go blind, not in those born blind). First there is sight, then there is no sight. But to cause is an activity. So the cause of this change, the blindness, must have activity, and hence, per the previous objection, must be an entity.

Aquinas responds to the first objection:

“We do not say that evil, considered abstractly, that is, the very evil, is the efficient cause of corruption. We say that evil so considered is the formal cause of corruption in that it is the very corruption of good. For example, we say that blindness corrupts sight in that blindness is the very corruption or privation of sight. And the evil, if it is, indeed, absolutely evil (i.e., evil in itself as such), indeed corrupts (i.e., brings something corrupt into actuality and as an effect) by nonactivity (i.e., by deficiency of active power), not by activity . . . But what is not evil absolutely and as such, causes complete corruption by its active power, not absolutely but of something” [13].

So evil considered absolutely as such, in itself (as we discussed above) is not an efficient cause of corruption but rather its formal cause, i.e. it just is that corruption or privation itself. In other words, blindness in itself does not cause blindness, it just is the blindness, the absence of sight in an eye. To see how this works, let’s go more in depth in our blindness example. To keep from getting bogged down in complicated technicalities, let’s make things overly simplistic. In our example, the process of sight will be just this: light travels into the eye, through an optic nerve and into the brain; the brain then interprets this signal as an image which we are consciously aware of. In our version, the optic nerve has two activities: it receives a signal from the eye and passes it on to the brain. But let’s say that, for us, blindness is causes by a defect in this nerve; its activity becomes disordered, and now, though it receives the signal, it fails to pass it along to the brain. In this case, the blindness itself is caused by an “inactivity”, the inactivity of the nerve delivering a signal to the brain. The nerve is defective; it is deprived of its proper good, and this absence of its good is really what causes or results in the blindness, since if the good were there the blindness would not be. So blindness is a real effect of an inactivity. But it is not the inactivity in itself that is the efficient cause of the blindness considered as the privation of sight in an eye. The nerve is only defective because it is an actual nerve in an actual eye that is directed towards some actual end which it is prevented from realizing. The efficient cause, thus, is whatever actually brought about the state of affairs in which the nerve became defected. And this efficient cause will not be “evil absolutely as such”, but will just be as the water was to the fire above: something that in itself is good but is evil in relation to the good of something else.

His response to the second objection:

“Corruption in the formal sense signifies being corrupted, neither causing movement nor acting. And corruption in the active sense signifies causing movement and acting, yet in such a way that everything therein regarding action and movement belongs to the power of good, and everything therein regarding deficiency belongs to evil in whatever way the latter is understood. For example, everything regarding movement when one is lame is due to the power of walking, and the lack of straightness in the limb is due to the limb’s curvature. And fire produces fire insofar as it has such a form, but fire causes water to cease to be insofar as such a privation is connected with the form of fire” [14].

This largely reiterates what has been said. What is significant and profound about this is that it reveals that evil derives all its power and efficacy from good, not from itself. In other words, “evil” considered absolutely is essentially a parasite. Cavities are real and hurt — they have real power to cause real pain and suffering. But a cavity is only bad because it is parasitic upon some actual good, namely the tooth. If the tooth were not there, the cavity wouldn’t be either; it would lose all its power and efficacy to harm. Evil derives all its force from the good which it is perverting and corrupting. Consider someone walking with a limp. This is a privation of the good of walking fully and healthily. But it is only an evil insofar as it presupposes the actual good of walking. The walking in itself is good; what is bad about it is that it is defective, lacking the full and whole ability to walk as human beings are meant to. Evil is evil because good is really good and is so powerful in itself. What is bad about evil is that the good which it corrupts is so good and meaningful in itself, that its absence is so noticeable and so felt and so horrendous. To recognize evil is above all to recognize that it is not meant to be that way. It is a departing from that way things should be. Evil is so horrible precisely because good is so profoundly great and glorious.

Thus we conclude our commentary on the first article of Question One of Aquinas’s De Malo.



[1]. Aquinas, Thomas. On Evil. Translated by Richard Regan, edited by Brian Davies. New York: Oxford University Press, 2003. Q. I, Art. 1, Obj. 2.

[2]. Ibid. I, 1, On the Contrary.

[3]. Ibid. I, 1, Answer.

[4]. Ibid.

[5]. Ibid.

[6]. Ibid.

[7]. Ibid.

[8]. Ibid.

[9]. Ibid. I, 1, Objection 1

[10]. Ibid. I, 1, Reply 1

[11]. Ibid. Objection 8

[12]. Ibid. Objection 9

[13]. Ibid. Reply 8

[14]. Ibid. Reply 9

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