God's ontological perfection and moral goodness

Divine impeccability has been traditionally considered an aspect of God's perfect ontological goodness. Contrary to this notion, many contemporary accounts of divine impeccability tend to separate God's ontological goodness – the goodness He has insofar as He is a being – from God's moral goodness – the goodness He has by having a good will and acting in a good fashion. Reichenbach (Reference Reichenbach1980) and Brown (Reference Brown1991) state that Aquinas's claim that God is good by nature does not imply that He is good in His actions, so ontological goodness does not guarantee moral goodness. Wierenga states that Aquinas's claim that ‘God is good’ qua desirable and first cause of all desirable perfection is an ontological or aesthetical claim that must be distinguished from the same claim taken as a moral judgement, which would be the relevant sense for a discussion about impeccability (Wierenga (Reference Wierenga1989), 202).

Contrary to these positions, God's moral goodness is for Aquinas directly linked to His ontological perfection or, more properly speaking, both in Him are one and the same thing. However, in order to understand this claim, it is important to provide some relevant background. As it is well known, for Aquinas goodness is a property of being as such (Summa Theologiae [hereafter ST] Ia, 5, 1).Footnote ¹ Every being is good insofar as it is desirable, since the desirability of a thing depends upon its perfection, and the act of being is the first and most radical perfection of every thing (ST Ia, 5, 1; also De veritate [hereafter DV] 21, 1). Now, since God is the primary cause of the perfection of every being, He is self-subsisting being itself and pure act or perfection, pre-containing all the perfections of every created being (ST Ia, 4, 2). He does not just possess goodness, but He is the supreme and absolute Good, not contained by any particular genus or order of created goodness (ST Ia, 6, 1 and 2). Moreover, given God's simplicity, for Aquinas, God is essentially good; He is Goodness itself, in whose goodness every other thing participates.

In this sense, God's goodness is metaphysically incompatible with any kind of evil. As it is well known, following Augustine, Aquinas defines evil as a privation or defect of a due good (ST Ia, 48, 1), as he says: ‘. . .evil according as it is evil is not numbered among the things that are, but is a privation of some particular good, inhering in a particular good’ (De malo [hereafter DM], 1, 1).Footnote ² Now, any privation requires a subject to exist; therefore, privations can only exist in those individuals that are not identical with the properties they possess. Only an individual that is not identical with the properties it possesses is able to acquire or lose any perfection. Now, for Aquinas, the distinction between an individual substance and its properties is a formal effect of the composition between actuality (being) and potentiality (essence), which can be found in all created beings (Summa Contra Gentiles [hereafter SCG] II, ch. 52). Hence, according to Aquinas, there can only be genuine privation or lack of perfection in those beings in which some metaphysical composition can be found, i.e. in the creatures. God, however, is metaphysically simple, given that He is pure actuality of being (ST Ia, 3, 4), therefore, no evil can be found in Him:

The preceding argumentation, isolated from its metaphysical framework, could be interpreted as referring exclusively to God's ontological perfection and not to moral perfection. One may feel inclined to think that, since God is ontologically perfect, he is the most desirable being, and therefore He is perfectly good only in this sense. Hence, one could say, no ontological imperfection or privation can be found in Him with regards to His nature, but that doesn't prevent God from ‘acting’ in an evil fashion, in spite of His ontological goodness. God's metaphysical perfection would not guarantee his moral perfection.

Such an interpretation would miss the main point of Aquinas's metaphysics of divine simplicity. For Aquinas, the composition of substance and accidents, which can be found in every creature, is a consequence of its composition of being and essence (SCG II, ch. 52). Since no creature is essentially its own being, no creature has, by virtue of its own nature, all the perfection that it is capable of (and that it aims to achieve), and which belongs to the scope of the accidental being. For this reason, every creature is oriented towards an ultimate end distinct from itself, and so has to attain that end through its actions, which are accidental properties, distinct from its substantial being. This is why in every rational creature the ontological goodness and the moral goodness are two distinct features.

God, on the other hand, is an absolutely simple being, with no composition of being and essence, or of substance and accidents (ST Ia, 3, 4 and 3, 6). Thus, He is not distinct from any of His attributes; He has, by His own nature, infinite goodness and perfection. Therefore, He doesn't need to achieve an end distinct from Himself through His actions. Moreover, His actions are not something distinct from His substantial being. Hence, God has in one simple act all the perfection that creatures can only have unfolded through different and successive instances (ST Ia, 4, 2):

By virtue of His metaphysical perfection God has, by His own nature, all the goodness that creatures can only acquire through their actions – or, eventually, via virtues infused by God. Now, the perfection that rational creatures achieve through their free actions is what is properly called ‘moral goodness’. Only in rational creatures does metaphysical and moral goodness unfold as two distinct perfections. Hence, for Aquinas, God's essential goodness includes the perfection of all kinds of goodness, even moral goodness. Since God's ontological perfection includes moral perfection, and His ontological perfection is absolute, then He also has perfect moral goodness, including moral virtues:

God's goodness and necessary impeccability

This conclusion clearly sets Aquinas's position apart from a certain number of contemporary accounts of divine impeccability. Many contemporary scholars (see Pike (Reference Pike1969), Reichenbach (Reference Reichenbach1980), and Brümmer (Reference Brümmer1984) ) hold what Carter has called the ‘divine office position’ (Carter (Reference Carter1982) ). According to this position, the term ‘God’ is a descriptive expression, a ‘title’ with an identifiable meaning, which contains necessarily the attributes ‘perfectly good’ and ‘omnipotent’, so that the proposition ‘God cannot sin’, would be necessary de dicto. To affirm of some individual, for instance, ‘Yahweh’, that He is ‘God’ is to affirm that that individual holds that title, i.e. that he occupies the ‘divine office’. Now, ‘Yahweh’ holds the title ‘God’ contingently, so that if He were to sin, He would no longer hold the office.

Things are quite different for Aquinas's classical position. Absolute and perfect ontological goodness can only be possessed by the only one individual who actually and essentially possesses it. Now, if God is morally perfect by virtue of His ontological perfection, which can only be possessed by the individual that He is (since He is the only possible instance of pure act (ST Ia, 11, 3) ), it follows that He is essentially and necessarily morally good. Therefore, He is also necessarily impeccable, i.e. it is metaphysically impossible for Him to sin, or to do evil: ‘Divine will has by its own nature not being able to sin’ (Scriptum super Sententiis [hereafter SS] II, d. 23, 1, 1).Footnote ⁶ Now, in order to properly understand this thesis, it is necessary to clarify Aquinas's concept of ‘sin’.

In a broad sense, sin can be regarded as a species of evil, namely, the privation, defect, or disorder affecting a natural or a voluntary action: ‘Sin, whether it be spoken of in natural or artificial or voluntary matters, is nothing but a defect or disorder in the agent's proper action when something is done otherwise than as it should be. . .’ (DV 24, 7).Footnote ⁷ Strictly speaking, ‘sin’ is a specific kind of evil that affects the actions of the will, consisting in their disorder or deviation from their proper end, which is also called ‘evil of fault’ (malum culpae) (DM 1, 4).

If sin or evil of fault is a defect or disorder of the actions of the will, it can only be found in a naturally fallible will. As is well known, Aquinas conceives the nature of the will as a rational tendency (appetitus rationalis) towards the perceived good (ST Ia, 82, 1). Every will tends towards good by its own nature, so evil is never directly intended as such by any will, but only per accidens, insofar as it is linked to some good: ‘The will naturally tends to good as its object. That it sometimes tends to evil happens only because the evil is presented to it under the aspect of a good’ (DV 24, 8).Footnote ⁸ For Aquinas, when a free creature sins, the creature chooses an apparent good, willingly not considering the rule of law that it should act in accordance with (DM 1, 3). This means that there can only be sin in a will whose goodness or rectitude is not intrinsic, but depends on the accordance of its own action with a rule distinct from itself (which makes it possible to deviate from the rule) (DM 1, 3). If a finite will has to adapt its action to a rule distinct from itself, it is because, even if it is naturally ordained towards good in general, it does not have the absolute and perfect Goodness as its natural object. Indeed, for Aquinas, only God's will, which is identical with His being, can have perfect and absolute Goodness as its natural object, whereas any finite will cannot (ST Ia, 6, 3). Hence, given that the finite created will always has to choose between particular goods and without immediately seeing their connection to the absolute Goodness, it can always reject any of them voluntarily. This is why, for Aquinas, every creature with free will, insofar as it is created from nothing – i.e. insofar as it is the free will of a composed being – is naturally fallible, while God, who is not a composed being, wills always naturally and indefectibly the good:

In this argument Aquinas explicitly links God's ontological goodness or perfection and simplicity with His natural inability to sin. Given that God is the individual He is, i.e. the only instance of pure actuality, His free will is naturally ‘confirmed’, i.e. fixed, in good. The natural object of His will is His perfect Goodness, from which He cannot back out. The divine nature is uncreated, and is identical to its own act of being and its own goodness; there cannot be any deficiency in it (SS II, d. 23, 1, 1), and hence ‘to have a goodness incapable of failure is the characteristic of God's nature’ (DV 24, 7). Natural and necessary impeccability is an exclusive property of God's nature and, as such, it cannot be naturally communicated to any creature, although it can be bestowed to rational creatures through grace and in glory (DV 24, 9).Footnote ¹⁰

From the preceding argument it follows that for Aquinas the proposition ‘God cannot sin’ expresses a metaphysical necessity, and not just a de facto impossibility. The proposition ‘God cannot sin’ is thus necessary de re, and not only de dicto. In other words, impeccability is not an essential property just of the ‘divine office’, but rather an essential property of the individual who, being pure actuality, necessarily holds the office. If, per impossibile, God would sin, He would completely undo His own nature and existence, and not just lose His job, but also destroy his own act of being.

Impeccability, will, and power

The thesis that God's inability to sin derives from a metaphysical necessity goes against another recurrent account of divine impeccability according to which it is just a feature of God's moral character. Pike (Reference Pike1969, 215–216), Reichenbach (Reference Reichenbach1980, 61), Brümmer (Reference Brümmer1984, 213–214), and, more recently, Manis (Reference Manis2011), have stated that the proposition ‘God cannot sin’ means that God has a strong disposition towards good that provides the material assurance that He will in fact not sin, or even that He would not sin in any possible world.Footnote ¹¹ Hence, even if God has the power to sin,Footnote ¹² He could not bring Himself to do it, in virtue of His moral character.

For Aquinas, this position is excluded not only by the general arguments expressed above, but also more specifically by the relation he establishes between God's will and God's power. Nevertheless, this issue has not always been understood correctly, particularly with regard to a very well-known argument presented by Aquinas. In several places, he tries to make sense of a statement by Aristotle according to which ‘God can do evil things’ (potest Deus prava agere) (Topic. iv, 3). Explaining one of the possible senses in which this statement can be interpreted, Aquinas says:

Pike rejects Aquinas's interpretation of the Philosopher's claim saying that ‘God can do evil things if He will’ is not really a conditional statement (Pike (Reference Pike1969), 211).Footnote ¹⁴ He may be right concerning that precise grammatical formulation, in which case the conditional should be reformulated as follows: ‘God could do evil things if He could will to do them’. It therefore seems to me fairly clear that Aquinas presents a counter-possible statement, whose only point is to establish that if God had the power to will evil things, He would have also the power to do them.

An alternative interpretation of this text must also be excluded. According to Morriston, Aquinas's quoted argument allows for a distinction to be made between God's ‘basic power’, i.e. the power of making choices, and God's ‘conditional power’, i.e. the power of actualizing states of affairs other than choices (Morriston (Reference Morriston2001), 154). According to this distinction, God could have the ‘conditional power’ of actualizing some states of affairs (e.g., evil states of affairs) that He has not the ‘basic power’ of bringing Himself to choose. This distinction seems to be supported by some parallel texts in which Aquinas suggests that God's power has a broader extension than God's will: ‘this statement is true: if God wills to sin, He can sin. It follows without condition, if one argues assuming the impossible: God wills to sin, so He can sin. Since everything He wants, He can, but not vice versa’ (Quaestiones de quodlibet [hereafter QQ] V, 2, 2).Footnote ¹⁵

This interpretation, however, is not correct. When Aquinas says that God can do everything He wills, but not vice versa, he means to say only that God does not actually want to create or actualize everything He could create or actualize. This does not imply that God's absolute power goes beyond what God is able to will. In fact, for Aquinas, the opposite is true. Given divine simplicity, will and power are one and the same thing in God. And, being a rational agent, God cannot act apart from His will, so everything that is impossible for Him to will is, absolutely speaking, impossible for Him to do: ‘Since He is an agent by will, He cannot do those things which He cannot will’ (SCG II, ch. 25). In other words, the fact that God cannot will something is not an extrinsic restriction of God's power, but just a sign of its real scope.

In the case of divine inability to sin, the identity between the scope of God's will and the scope of God's power established by Aquinas's argument is clear. As shown above, for Aquinas to sin is to perform an evil (i.e. a defective or disordered) act. Willing to sin implies having already a disordered will; hence, willing to sin is already a sin in itself. If willing to sin is impossible for God, then it is impossible for Him to sin, i.e. to perform a disordered act of will. Hence, for Aquinas the truth of the proposition ‘God cannot will to sin’ is not grounded on a contingent feature of God's moral character.

On the contrary, Aquinas provides several arguments to prove that that proposition is a necessary truth, and that God's will excludes by necessity the power to sin. All of these arguments are grounded either directly in God's nature, or in the nature of God's faculties as a perfect being. I will call the former ‘ontological’ arguments, and the latter ‘operative’ arguments.

The first of the ‘ontological’ arguments is based on God's simplicity, and presupposes the identity between God's nature and God's virtue, through which He produces all things: ‘the virtue of a thing is that by which one produces a good work. Now every work of God is a work of virtue, since His virtue is His essence, as I have shown above. Therefore He cannot will evil’ (SCG I, ch. 95).

The second ‘ontological’ argument is based on the unchangeable character of the divine nature, which is incapable of undergoing any mutation caused by God's will. God cannot will to sin because, as seen in the previous section, not being able to sin is a feature of God's nature, and His will does not have power over His own nature:

In their turn, ‘operative’ arguments are based on the perfection of three different faculties: intellect, will, and power. In the first place we find an argument based on the infallibility of God's intellect, which cannot err in discerning the real good from the apparent good, in which sin is based:

In the second place, there are ‘operative’ arguments based on the natural object of divine will. One of them is based on divine goodness as the primary, natural, and necessary object of God's will:

Another argument taken from the object of God's will is based on the assumption that divine goodness is the means through which God wills every secondary object of His will:

Finally, Aquinas also provides an argument for the impossibility of God's willing to sin based on God's absolute power, i.e. His omnipotence. This argument is more controversial, and challenges many established assumptions on the issue, so I deal with it in the next section within the context of contemporary discussion on the compatibility between impeccability and omnipotence. So far, however, I assume I have proven that, for Aquinas, God's inability to sin is not just a feature of God's moral character, but a metaphysical necessity directly grounded on the identity of God's will and power, and ultimately grounded on His nature.

Impeccability, omnipotence, and liability

The contemporary accounts of de dicto divine impeccability mentioned above have been proposed as a way of avoiding two main recurrent arguments against the Classical Theist conception of impeccability as a metaphysically necessary inability to sin. In the first place there is the argument based on the apparent incompatibility between impeccability and omnipotence. Even though this argument is not new, it has received many recent formulations,Footnote ¹⁷ all of which may be summed up as follows: an omnipotent being should be able to bring about any consistently describable state of affairs; there are some consistently describable (i.e. logically conceivable) states of affairs, the production of which would be morally reprehensible, and which a perfectly good being could not bring about; therefore, there cannot be an omnipotent and perfectly good being.

Even if Aquinas never addressed the problem in those terms, in a very well-known place of his Summa Theologiae he presents an argument for God's impeccability that has been mistakenly regarded as a sort of counter-argument for the above-mentioned difficulty: ‘To sin is to fall short of a perfect action; hence to be able to sin is to be able to fall short in action, which is repugnant to omnipotence. Therefore it is that God cannot sin, because of His omnipotence’ (ST Ia, 25, 3, 2). Pike (Reference Pike1969, 210)Footnote ¹⁸ and Davis (Reference Davis1983, 87–88) have criticized this argument, interpreting the expression ‘to be able to fall short in action’ in terms of moral weakness, a feature that they find logically conceivable, and therefore ascribable to an omnipotent being.

These critiques are inadequate because they assume that ‘omnipotence’ means something different from what it actually means for Aquinas in the context of the quoted argument. What is the meaning of ‘omnipotence’ in the context of the argument? In a parallel text, Aquinas explains that there are two ways God is said to be ‘unable to do something’: one of them concerns His power and the other concerns the possible things considered in themselves (DP 1, 6). Regarding the second alternative, God is said to be unable to do something when the thing in question implies a contradiction (DP 1, 6). This sense of God's inability is correlative to his classical definition of omnipotence, based on logical non-contradiction (ST Ia, 25, 3).Footnote ¹⁹

Regarding the first sense in which God is said to be ‘unable to do a thing’, Aquinas states the following: ‘His power considered in itself, since it is infinite, lacks nothing that appertains to power’ (DP 1, 6),Footnote ²⁰ and so He is unable to do anything that implies in itself a lack of power. Even if it is not a proper definition,Footnote ²¹ omnipotence is described here as ‘infinite’ power, meaning that we can attribute to God everything that can be properly called a ‘real and positive power’, as opposed to mere ‘nominal’ power. For Aquinas, sometimes we describe as ‘powers’ some things that are really a lack of positive and real power. These things are imperfections and therefore cannot be predicated of God:

It can be concluded then that the ability to sin, i.e. of ‘falling short in action’, must be regarded as a liability, a lack of power, a merely ‘nominal power’. This does not entail, as Morriston suggested in his interpretation of the argument above, the denial of the existence of the ‘akratic’ power of knowingly choosing evil (Morriston (Reference Morriston2001), 157).Footnote ²² It rather means, as Morris suggested, that there is no discrete power of sinning, no power the exercise of which is, in itself, sufficient for doing evil (Morris (Reference Morris1986), 165–168).

Indeed, a sin is an act of the will and the will for Aquinas is a capacity essentially ordained towards willing the good and choosing good objects and actions. Even in sinning the will tends to an apparent good, or to a real good, but in a disordered way. Thus, being able to sin does not add any specific object to the natural capacity of the will. In other words, ‘sin does not specify the power of free will’ (SS III, d. 12, 2, 2). There is no specific good that can be willed or any specific end that can be achieved by sinning that cannot be willed or achieved through a morally good action. Since sin is a type of privation, the ability to sin is not provided by any distinctive capacity, but by a defect of the will: ‘given that the power of the human will is by its own nature ordained towards good, a defect from good in its own action is caused by some defect in it’ (SS II, d. 44, 1, 1).

Hence, if being able to sin is being capable of acting imperfectly, the expression ‘power to sin’ does not denote any real power. It is rather just a name free will receives in those subjects that have a defective free will: ‘free will, as is evident from what has been said, cannot be called power of sinning absolutely speaking, unless in those [subjects] that can sin’ (SS III, d. 12, 2, 2, ad 7). As I shall explain later, for Aquinas the ability to sin is something present in rational creatures not as a specific feature, but as a resulting condition of the imperfect and finite mode in which they possess free will.

Omnipotence, non-contradiction, and evil

Aquinas's claim that God's omnipotence is not just compatible with impeccability, but that it is its ultimate foundation, makes clear sense if omnipotence is defined as ‘infinite power’, which includes only ‘real, positive, and non-nominal powers’. Nevertheless, using this argument as a reply to the problem of the apparent incompatibility between impeccability and omnipotence exposed above would be mistaken. As seen in the previous section, the way contemporary authors present the problem is based on a definition of omnipotence expressed in terms of logical possibility.

Many contemporary authors try to block the objection through a distinction between ‘conceivability’ and ‘real possibility’ (Hoffman (Reference Hoffman1979), Morris (Reference Morris1982), Flint & Freddosso (Reference Flint, Freddosso and Freddosso1983), and García (Reference García1984, Reference García1987) ), arguing a priori that there are some states of affairs the production of which would be morally reprehensible that, even though ‘conceivable’, are not ‘really possible’, or at least they are impossible for God to bring about, given His perfection (see Gellman (Reference Gellman1977) ). This line of argumentation has some disadvantages. First, it would not be an accurate argument for Aquinas, who defines omnipotence negatively in terms of non-contradiction, and claims that the conceivable and the really possible have equal extension (ST Ia, 25, 3).Footnote ²³ On the other hand, Pike and the other objectors provide concrete examples of allegedly morally unjustifiable states of affairs, accepted as such by their opponents, which are not only conceivable, but also actual (e.g., ‘an innocent child suffering a slow and tortuous death by starvation’) (Pike (Reference Pike1969), 209).

In order to solve this problem it is important to make some preliminary remarks:

(a) God's omnipotence does not imply for Aquinas that God can perform any task that is absolutely possible, since there are things that creatures can do, but God cannot, such as walking or being angry.Footnote ²⁴ Even if Aquinas defines the scope of omnipotence in terms of logical non-contradiction, not every consistently describable state of affairs can be an object of divine omnipotence. God's omnipotence implies that He can bring about all states of affairs that are ‘producible’ without a contradiction following.Footnote ²⁵

Now, even if for Aquinas creatures have the ability to do some things (such as walking or suffering) due to the imperfect degree in which they imitate divine perfection – and thus they cannot be attributed to God (SS I, d. 42, 2, 1) – God, as the primary cause of every being, has the power to produce every state of affairs the creature has the power to produce:

It is important to note that, in this case, God does not produce directly the state of affairs in question (walking or suffering), but produces substances with their own operative powers, which, as secondary causes, are the direct causes of those states of affairs. States of affairs such as walking or suffering have intrinsic requirements of actualization, which make it impossible for God to actualize them without the secondary causes being involved.

(b) For Aquinas, no consistent describable state of affairs is per se morally reprehensible, independently of other circumstances, including the condition of the subject who produces it. Sin is a voluntary action, whose moral value depends, among other things, on the quality and the intention of the subject who performs it. Indeed in his attempt to provide another possible interpretation of Aristotle's assertion ‘God can do evil things’, Aquinas says that this may be understood to mean that God can do some things which now seem to be evil which, however, if He did them, would then be good (ST Ia, 25, 3, ad 2).Footnote ²⁶ This assertion does not imply, as Pike interprets it (Pike (Reference Pike1969), 212), that the concept of moral goodness is equivocally predicated of God and creatures. It only means that the objective description of a state of affairs is not sufficient to define the morality of an action, without any further consideration. As Aquinas explains:

From these two remarks it can be concluded that the problem of God ‘being able to bring about morally reprehensible states of affairs’ requires taking into consideration: (a) the conditions or requirements of actualization of the possible states of affairs which are said to be possible but are excluded by divine impeccability; (b) the possible moral value that can be charged to the primary cause of those states of affairs. The problem, then, does not consist in determining whether those states of affairs are, per se and objectively, really possible and morally reprehensible, but whether there is any possible state of affairs in which God causes certain evils, and in which that causation can be regarded as a sin.

For Aquinas, this question has different answers depending on the type of evil considered. Regarding ‘moral evil’ (which Aquinas calls ‘evil of fault’), Aquinas clearly states that God cannot be its cause, either directly, or indirectly (ST I-IIae, 79, 1). A sinful act requires essentially for its actualization a defective free cooperation of the creature, irreducible to God as first cause:

The sinful act, insofar as it has being and actuality, is to be referred to God as to its first cause; but insofar as it has the deformity of sin, it must be referred to the creature's free will and not to God (DP 1, 6, ad 5). God is not even the cause of the ‘power of sinning’ in itself (SS III, d. 12, 2, 2, ad 6), since that power is a liability creatures have insofar as they come ‘from nothing,’ i.e. insofar as they are limited beings (DV 24, 3 and 7). Therefore, with regard to God ‘we cannot say that He can sin, or that He can produce sin in others’ (SS I, d. 42, 2, 1). The proposition ‘God causes moral evil’ or ‘God makes a creature sin’ implies a contradiction and does not express a possible state of affairs.

In the case of ‘physical evil’, which includes suffering, corruption, and natural evil in general, Aquinas says that it cannot be directly ‘caused’ by God; nevertheless, He can cause it indirectly or per accidens, as a secondary effect of the perfection of the universe, which would not be complete without all the degrees of being, one of which is corruptible being (ST Ia, 49, 2). For Aquinas physical evil is not evil in its primary sense, since it does not deprive rational creatures of the absolute goodness towards which they are oriented (ST Ia, 48, 6). Physical evil can be ordained towards a greater good for the creatures, and that is why physical evil can be an indirect object of God's will, if there is a sufficient reason to allow it.Footnote ²⁷ The proposition ‘God (indirectly) causes physical evil’ implies no contradiction and expresses a possible state of affairs, but this does not mean that God can sin in doing so, in the same way that a doctor does not sin in inflicting suffering to cure a patient.

Impeccability, free will, and praiseworthiness

Another frequent objection to the classical view of impeccability as a metaphysically necessary attribute is based upon its apparent incompatibility with free will and praiseworthiness. Reichenbach built this objection on Plantinga's definition of a morally significant free action (Reichenbach (Reference Reichenbach1980), 55). According to Plantinga, a person is free with respect to a given action if he is free to perform that action and free to refrain; in its turn, an action is morally significant if it would be wrong for someone to perform that action but right to refrain, or vice versa; finally a person is significantly free if he is free (i.e. can perform or refrain from doing it) with respect to an action that is morally significant for him (Plantinga (Reference Plantinga1974), 165–166). Based on these definitions, Reichenbach and also Morriston (Reference Morriston1985) claim that, if it is metaphysically impossible for God to choose evil (or to refrain from choosing good), then His actions are not morally significant free actions, so He does not deserve praise for them.Footnote ²⁸ This objection has led some theists to deny that God is significantly free, providing alternative ways of guaranteeing divine praiseworthiness.Footnote ²⁹

From Aquinas's perspective there is no need for making that move. As explained above, the ability to sin is not for him a real power, nor is it a specific capability that adds something to the nature of free will, but it results from freedom of choice as it can be found in creatures: ‘being able to sin, according to Anselm and Boethius, does not belong to the freedom of the will, but is rather a condition of the deficient will insofar as it comes from nothing’ (SS I, d. 42, 2, 1 ad 3).Footnote ³⁰ Hence, although free will in creatures is open to good and evil choices, it is not naturally directed towards evil, but only towards good (SS III, d. 18, 1, 2 ad 5).

Certainly, for Aquinas, free will excludes necessity, so the ability to act in a different way to which it actually does is an essential feature of the freedom of the will; when the will inclines to any object, it retains the ability to tend to the opposite object (DV 24, 10). This is so also in the case of God, who has free will with respect to those things that He does not will by necessity. This means that He is free with respect to His creatures, but not with respect to His own nature, which He loves necessarily: ‘God necessarily wills His own goodness, but other things not necessarily, as shown above, He has free will with respect to what He does not necessarily will’ (ST Ia, 19, 10).Footnote ³¹

Since God does not necessarily will anything different from Himself, He is free with regard to both the exercise and the specification of His voluntary actions, even if He is not able to sin:

Indeed, even though God lacks the ability to sin, the existence of every being other than Him depends on His free decision to actualize it, therefore ‘He can make choice of one of two opposites, inasmuch as He can will a thing to be, or not to be. In the same way we ourselves, without sin, can will to sit down, and not will to sit down’ (ST Ia, 19, 10, ad 2).Footnote ³²

One may object that this argument only proves that God has free will with regard to actions that have no significant moral content. If a free action is praiseworthy only in those cases in which one can refrain from doing evil, to sit down or not to sit down seems to have no moral value in itself. Aquinas prevents this type of objection by showing that praiseworthiness and moral significance does not have the same requirements in different subjects with different natures. Something laudable in a lower nature could be reprehensible in a higher nature, so that which is said in praise of man is not always becoming to the praise of God: ‘such as being fierce is praiseworthy in the dog and the lion, but is reprehensible in man, so not sinning, being able to do it, is praiseworthy in man, but it is a blasphemy if it is predicated of God’ (SS I, d. 42, 2, 1 ad 4).Footnote ³³

Aquinas's move allows for maintaining the validity of Plantinga's definition, but restricted in its extension to morally significant ‘human’ free actions. For Aquinas, the ability to sin does not contribute per se to the praise of an action, but only contributes to the manifestation of the free and voluntary character of the actions of rational creatures: ‘Nevertheless, the ability to sin concerns praiseworthiness only by accident, inasmuch as it shows that the praised action has not been performed by necessity’ (SS III, d. 12, 2, 1 ad 2).Footnote ³⁴

According to Aquinas, the only requisite for a free good action deserving of praise, i.e. to be morally significant, is that it must be performed by an agent who has control over it (SS III, d. 18, 1, 2). Praiseworthiness can only be suppressed by the ‘impotence of coercion’ (impotentia coactionis), which removes the voluntary character of the action; on the contrary, voluntariness (and, thus, praiseworthiness) cannot be removed by the ‘impotence’ that results from the perfection in goodness, which confirms the will to one alternative (ad unum) (SS III, d. 12, 2, 1, ad 3). The confirmation of God's free will in the good doesn't prevent Him from having control over His voluntary actions, because His will is not determined to one alternative with regard to any token or specific action, but with regard to the type (genus) of action, which is the good (SS III, d. 18, 1, 2, ad 5). Hence:

A creature naturally fixed or confirmed in good could not refrain from choosing particular tokens of actions, and therefore would not have control over them. On the contrary, since God's will is naturally fixed in His own goodness, but is not naturally bound to any other particular good, He could always refrain from willing what he contingently wills,Footnote ³⁵ without sinning. Hence, for Aquinas God can have control over His free actions, be praiseworthy and significantly free, without having the ability to sin.