1.1 Key areas of the doctrine of sin

Historically, some have divided sin into states of sin and acts of sin. Anselm classifies the former as ‘original sin’, and the latter as ‘personal sin’ (On the Virginal Conception 1; Anselm of Canterbury 2007). Thomas Aquinas agrees with the classification, though he calls personal sin ‘actual sin’ for reasons (we shall see below) that pertain to original sin being only analogical to personal sin (Summa Theologiae [ST] I–II. 82.1; Aquinas 1947). Original sin is congenital, and only up to four human beings are exempt: Adam, Eve, the Virgin Mary, and Jesus Christ. While many thinkers across various traditions exempt Christ from original sin and other sins, the Virgin Mary is predominantly (though not only) considered to be exempt from original sin in the Roman Catholic Church. Thinkers do not often comment upon Adam and Eve being exempt from original sin (cf. section 2.3). On pain of maintaining human beings are created sinful (or some such), it is worth specifying that ‘original’ designates a congenital property that Adam and Eve’s progeny acquire.

Personal sin is sin that individuals commit. The sinfulness of personal sin is located either in the individual’s action, intention(s), or the effects thereof. Original sin is historically considered the congenital condition humans acquire from their ancestors, Adam and Eve, because of the primal sin. The primal sin is the first sin of Adam and Eve, and, in some dialogues, the first sin of some angels. According to Oliver Crisp, any historical and orthodox doctrine of original sin involves at least three claims:

(1) there was an original pair from whom we are all descended;
(2) this pair committed the primal sin that adversely affects all their offspring;
(3) all human beings after the fall of the original pair are in need of salvation, without which they will perish. (Crisp 2019a: 145)

The above theses are quite minimal, and intentionally so. Crisp denies that historic and orthodox accounts of original sin maintain that sin is only an intrinsic property that individuals possess, for Orthodox theologians deny as much and instead highlight how sin is social and extrinsic in some way (Crisp 2019a: 145). Nevertheless, certain Orthodox thinkers diverge from more Western articulations of original sin (cf. section 4). Crisp also omits other historically associated claims, such as the transmission of sin, original guilt, and the claim that there is a penalty associated with inherited original sin. These three theses can be viewed as typical of orthodox doctrines of original sin.

The doctrine of original sin received one of its finer and more robust articulations in the hands of Augustine. According to Jesse Couenhoven, Augustine’s doctrine of original sin consists of five related though mostly independent claims:

(4) the primal sin of the first couple;
(5) the participation of the rest of the human race in that sin, because of our solidarity with Adam;
(6) involuntary and inherited sin in the two forms of a common guilt we suffer because we were in Adam when he sinned, and a constitutional fault of ignorance and disordered desire;
(7) a penalty to human nature assessed because of sin; and
(8) an account of how inherited sin and its penalty are transmitted from parents to children via sexual regeneration. (Couenhoven 2013: 46)

Couenhoven claims that, for Augustine, only thesis six is necessary for a doctrine of original sin. In other words, one could hold the remaining four claims (4–5, 7–8) and not subscribe to a doctrine of original sin. In agreement with Augustine, many early thinkers maintain that the human race suffers a wound from the primal sin, and that death is unnatural. (For other construals of original sin, cf. Rea 2007; Vainio 2021.)

In line with Crisp’s more dogmatically minimalist approach to original sin, other thinkers deny various aspects of the above Augustinian view. For example, some contemporary thinkers subscribe to a constitutional fault though deny original guilt (cf. section 3). Thinkers such as Aquinas deny that sin is transmitted seminally but is instead acquired by participation in Adam’s race (ST I–II.81.1; Aquinas 1947). Thinkers such as Peter Lombard deny that there is a penalty associated with exhibiting original sin, and rather maintain that those who die without committing personal sin will only lack the beatific vision. Not to be outdone, Augustine and Anselm maintain that infants would receive lighter punishment, though punishment nonetheless (Houck 2020: ch. 1; Wainwright 1988).

1.2 Defining sin

Before moving to core aspects of the doctrine, it is worth noting some attempts at defining sin. (For whether sin or evil are definable, see O'Donovan 2024: 13; Leftow 2022: 243–245.) When defining the concept of sin, one must decide whether ‘sin’ is a univocal term. Some authors maintain ‘sin’ is either ‘actual’ or ‘original’, and original sin is only sin in an analogous sense (Catechism of the Catholic Church [CCC] 1997, para. 404; Plantinga 1995: 26). Others maintain that ‘sin’ is an univocal concept that applies equally to original and personal sin (Couenhoven 2009; Leftow 2022; Anselm of Canterbury 2007, On the Virginal Conception). The motivation for the different positions may partially reside in whether sin is something that one is reasonably able to control or avoid, something for which one is responsible/culpable, and something that makes an individual a candidate for either punishment, atonement, or forgiveness. In other words, some of the motivation and significance is similar to issues that compatibilists and incompatibilists concerning free will and moral responsibility address (cf. Free Will). Cornelius Plantinga (1995), for example, claims that if we are culpable for original sin, it is a different culpability than what accompanies personal sin. However, the disagreement is not reducible to the issues that accompany (in)compatibilism. Thinkers also disagree over whether sin includes states of being, such as dispositions and attitudes, in addition to acts.

The question of defining sin is different from how to classify sins appropriately. When classifying sins, one distinguishes between different types. In this vein, one might distinguish between mortal and venial sins, intentional and unintentional sins, or between sins against God, against other human beings, and sins against oneself (for more, see McCall 2019: ch. 5). This entry deals with classification when relevant in the appropriate sections. The question of defining sin pertains to the definiens and the definiendum. Thinkers typically agree that an adequate definition of sin – the definiens – must at least capture certain traditional Christian commitments – the definiendum. Some of these commitments include claims that only persons sin, that sin makes an individual a candidate for either punishment or forgiveness, and that sin causes a barrier between humans and the divine, or humans and other humans. (For examples of such lists, see Leftow 2022; Couenhoven 2009.)

1.3 Sin in theological context

The doctrine of sin relates to and affects several other areas of Christian doctrine. This section notes a few of these in brief. First, the doctrine of sin, especially when sin is considered as a perversion and a result of the fall, is best placed in the context of the doctrines of God and creation. According to many thinkers historic and contemporary, God is the good creator of all that exists aside from Godself, and God only creates good things. Since God is the creator of all things and sin is not good, many thinkers will maintain that sin (and evil more generally) does not – ontologically speaking – exist (Hart 2005; McFarland 2014: 114; Lee 2007: 470; Aquinas 2003: 58). Such a claim aims to preserve the goodness of creation and God’s sovereignty. To claim that evil is only a privation or distortion of goodness also implies that evil is not a substance or entity of any sort. (For a recent overview and criticism of this connection, see Haratine 2023.)

The doctrine of sin also bears upon issues of free will and responsibility. As section 2.1 describes, one of the keys to discussing the ‘primal sin’ is to secure a view of a free act that does not place the responsibility for the fall of the first humans or angels on the divine side. (For recent literature on these issues, see Grant 2019; Furlong 2019; Wessling and Turner 2023.) Issues of free will and determinism also play a role in discussions about the inevitability of sin, a claim that many (though not all) thinkers include within their understanding of the doctrine of original sin. If it is the case that one is born with a corruption that will inevitably lead them to commit some act of sin, then it is difficult to see how the individual is responsible for that act of sin (cf. section 3.4).

The doctrine of sin will also partly affect the doctrine of atonement to the degree that divine atonement is seen as a response to – or remedy for – the manifold problems that sin produces. The view of sin that underlies the atonement will affect how one formulates the doctrine of atonement. On the one hand, the view of sin corresponds to the divine attribute emphasized, for it is a perversion of that attribute; on the other hand, the view of sin influences the proposed remedy that the specific theory of atonement provides (Johnson 2017). For example, as for Anselm, if sin is a failure to pay a debt of honour, the divine attribute of honour is emphasized, and Christ’s sacrifice must satisfy this honour for humanity’s debt to be paid.

Similarly, the doctrine of sin relates to the doctrines of justification and holiness. For example, concerning the church’s holiness, Karl Rahner adamantly maintains that the church is presently sinful rather than risk considering the justified and holy church as an entity existing independently over and above the members of the church, detached from the present individuals that comprise the church as pilgrims (Rahner 1982: 276–77). Rather than distinguish the church’s status as holy from the church’s sinful state, Rahner maintains that the church is holy insofar as Christ’s grace and efficient work are given to the church prior to any actions her members take (Rahner 1982: 290–291). The doctrine of sin also bears on individuals’ justification and holiness, a tension that Martin Luther resolves, roughly speaking, by considering Christ’s righteousness imputed (not imparted) to individual sinners (Luther 2006: ch. 2; Rahner 1982: ch. 15).

Some authors contest whether the doctrine of sin must include the doctrines of the fall or original sin. Existential and allegorical understandings of the fall or original sin tend to elide the need for these doctrines. This article will not address in depth allegorical and/or existential understandings of the fall. (For a defence of these views, see Spencer 2023; Torrance 2023: ch. 6; and Science and Falleness; for an overview and criticism of these and similar views, cf. McFadyen 2000: ch. 2; Smith 2017; McCall 2019; Haratine 2025.) One criticism of allegorical accounts is that such views fail to secure the universal human need for Christ’s atoning work.

2.1 Primal sin

The primal sin refers to the very first sin. Depending on the focus of the discussion, the primal sin may refer to either Adam and Eve’s first sin or the rebel angel’s first sin. Thinkers also refer to the first or lead rebel angel as Lucifer, Satan, or the Devil. Because historic discourse about the primal sin experiences its height in the medieval period, this section will avail itself of medieval thinkers.

The generic discourse of sinful acts typically involves discussion of how factors may lead an individual to sin. According to many in the tradition, an individual’s sin may be accounted for primarily in terms of the intellect or the will (McCluskey 2017).

Generally speaking in these discourses, the factors that may contribute to an individual sinning are either inherent, such as inherited concupiscence or ignorance from being a fallen human in the line of Adam (as per Augustine), personally acquired, such as an acquired vice of greed, or otherwise specific to the states of affairs present when one sins, such as an individual not having taken notice of a divine command or rendering themselves subject to the relevant passion. The question of whether individuals may commit clearheaded sin is a centre of dispute in the medieval period.

In contrast to generic discourse on sinful action, the primal sin offers a case study of why a good created agent might sin, an agent without any defect, lack, or other disturbing factor. The first angels were well equipped with the capacity of a will and intellect to obey and love God. The first angels, further, knew that they ought to love and obey God, and they did not have any ill-formed habits. In other words, the first angels had no inherited, acquired, or otherwise concurrent factor negatively influencing their decision. How is it, then, that the first angels fell? The primal sin is a case study of moral psychology, God’s causal activity, God’s providence, and divine and creaturely responsibility.

Following the work of William Wood (2016), the problem of the fall divides into two partially independent questions: the hard problem and the harder problem (see Hoffman 2012: 285 for a subtly different characterization). The hard problem of the fall is to provide a satisfactory account of how the angels’ sinful choice is both free and morally significant. If everything that God has made is good and without defect, how does evil enter the created order? Should an answer to the hard problem of the fall indicate that the angel’s choice to sin was not relevantly free, it would seem to indicate that God is responsible for causing some angels to fall and not others. This would be unsatisfactory to the degree that it makes God the author of the fall and the first sin(s). Should an answer to the hard problem fail to indicate that the choice to sin was morally significant, such an answer would not adequately explain the angels’ responsibility and the fall’s adverse and merited effects.

The harder problem of the fall is to provide a satisfactory answer to the question of how such a choice to sin is subjectively rational for the angel to commit. Supposing that one fully addresses how the Devil’s first sin was metaphysically possible, free, and morally significant, one still has not provided an account of why the Devil so chose. Further, one has not provided an answer to why only some angels fell. The harder problem of the fall is why a good agent without lack or defect would choose to disobey God. Should an answer to the harder problem of the fall fail to indicate that the sin was subjectively rational, then the first problem rears its head, for there would seem to be a defect in the initially created order.

Our discussion will focus on two historic figures, Anselm and Thomas Aquinas, to illustrate possible answers to the hard and harder problem of the fall. Anselm and Aquinas, for present purposes, may be thought of as respectively representing voluntarist and intellectualist positions. According to a voluntarist account of motivation and action, individual acts are explained primarily in terms of the will. According to an intellectualist account of motivation and action, the intellect and its reasons ultimately explain the agent’s action. For the primal sin, the sinfulness is explained primarily in terms of either the intellect or the will.

Anselm is generally regarded as a libertarian, and he provides a voluntarist understanding of why the first angels fell (for more on this discussion, cf. Visser and Williams 2009; Haratine 2024). Anselm maintains that God endows rational creatures with two motivational dispositions, dispositions in virtue of which the rational agent is freely able to commit specific acts: the disposition for happiness and the disposition for justice. In his famous dialogue, On the Fall of the Devil, Anselm maintains that rational creatures must have some motivational dispositions to initiate any specific and occurrent volitions. Otherwise, there would be a vicious regress of specific volitions, an agent always requiring one more previous volition to explain the occurrent volition. Moreover, a rational creature must have both motivational dispositions to will freely and in morally significant ways. If the angel only had a will for happiness, the angel would be compelled to will objects for the sake of happiness (mutatis mutandis for justice) (On the Fall of the Devil 12–14; Anselm of Canterbury 2007). By endowing rational creatures with two distinct motivational dispositions, Anselm secures the conclusion that the angel’s primal sin was free and, thus, that the responsibility was not traceable to God. When the student presses Anselm as to why only some angels fell and not others, Anselm responds that no cause preceded the will. It was also not because the angel could will, because others could, too. Rather, the will was its own efficient cause (On the Fall of the Devil 27; Anselm of Canterbury 2007). (For commentary on this passage, cf. Rogers 2008: 97.)

Anselm’s voluntarist account addresses the hard problem of the fall to the degree that it explains how the first angel’s sinful action is free and morally relevant. On this score, Anselm is fairly like Augustine (Augustine of Hippo 2010: III.17.48; 2004: XII.6; King 2012; MacDonald 1999). However, Anselm offers a welcome development to Augustine regarding the hard problem of the fall. Where Augustine maintains that God only gives some angels the gift of perseverance, Anselm maintains that God gives all the angels the gift of perseverance, though only some accept it. So, Augustine’s account seems to place some of the causal responsibility of the fall on God’s side; Anselm attempts to place this causal responsibility on the creature’s side.

Anselm’s account also attempts to explain the harder problem of the fall. Anselm takes great pains to show that the angels were aware of their responsibilities and that to sin would deserve punishment. However, since the angels knew that God is as just as he is merciful, they did not know whether they would be punished and fall for their disobedience (On the Fall of the Devil 21–24; Anselm of Canterbury 2007). In other words, there was no intellectual defect, such as a cognitive error or a nonconsideration of God’s command. For Anselm, this means that the angel wasn’t willing something in knowledge of its imminent demise, and in this sense, the action was subjectively rational.

Nevertheless, Anselm’s answer less clearly explains the harder problem of the fall to the degree that, as a voluntarist, the final explanation of the primal sin seems to be a brute volition. The choice seems mysterious to the degree that nothing aside from the volition exhaustively explains the volition, and nothing seems to explain why only some angels fell and others did not. (For more on Anselm’s view of choice, cf. Normore 1998.) Similar to contemporary sourcehood accounts of libertarianism, Anselm’s answer seems to bottom out in mystery. Nevertheless, Anselm offers a voluntarist solution to the primal sin since, insofar as the angel willed ‘something extra’ before God so willed it, the defect of the primal sin lies within the volition. (For a defence of Anselm’s account, see Wood 2016.)

Aquinas, in contrast, is an intellectualist and consequently maintains that the will follows the intellect’s judgement (this gloss follows Hoffman 2012; 2020: ch. 8). Should a rational creature act sinfully according to the intellectualist, the sin requires the presence of a cognitive error, an omission, or a nonconsideration. Aquinas famously thinks that the will always wills or desires what it perceives as good, sub ratione boni. So, if the will pursues something evil, it is not because it perceives it as evil, but as good; the intellect has committed some error, is ignorant, or does not consider something.

Accordingly, Aquinas maintains that the first sin of the angels was not due to error or ignorance. On the contrary, the angels had a perfect knowledge of God’s command and ordering for them. Rather, the angels failed to fully consider the rule governing them, and instead aspired to attain things on their own steam. Aquinas writes:

Evil consists both of the privation of form and the privation of due measure and order, as Augustine says in his work On the Nature of the Good. And so acts of the will have evil both from their object, which gives the acts their form because one wills evil, and from taking away the due measure or order of the acts themselves, as, for example, if one in the very course of willing good does not observe due measure and order. And such was the sin of the devils that made them evil. For they desired a suitable good, not an evil. But they desired it inordinately and immoderately, namely, in that they desired to acquire it by their own power and not by God’s grace, and this exceeded the due measure of their status [...]. [R]egarding sin, defect of intellect or reason and defect of will always accompany one another proportionally. And so we do not need to suppose that there was in the devils’ first sin such a defect of intellect and they judged falsely (e.g., that evil is good), but that they failed to comprehend the rule governing them and its ordination. (Aquinas 2003: 450)

According to Aquinas, the angels did not will something inherently bad, but willed some good object by their own means without fully considering their actions in light of God’s rule. They sinned because they willed the good object on their own, though they had been ordained to do so by God’s grace. This sin is not an error, in thinking that a bad object was good; and it was not in ignorance, not knowing they should rely on God’s grace. Rather, it is due to a nonconsideration of God’s rule.

Hoffman elaborates upon Aquinas’ claim that the good angels fell for lack of proper consideration of God’s rule:

Aquinas’s account of nonconsideration in angelic sin can be compared to people who damage a new technological device because they did not read the instruction manual. In the normal case, this happens not because they read the manual and intentionally disregard its instructions, nor because they are unaware of the existence of the manual, but rather because they feel confident that they can use the device without further instructions. (Hoffman 2020: 210)

How does Aquinas’ answer address the hard and harder problems of the fall? Regarding the hard problem of the fall, since the angels had full knowledge of God’s ordinance (the instruction manual), they were not ignorant. Further, they did not misunderstand God’s ordinance and err in their understanding. Rather, they failed to consider the ordinance adequately. The defect is therefore intellectual in nature, and the sinful choice is free and morally significant insofar as the angels ‘controlled how habitual knowledge becomes an occurrent practical judgment that is followed by the corresponding choice’ (Hoffman 2020: 211). This control originates from the will making the ‘intellect deliberate about whether to exercise its act’ (Hoffman 2020: 213).

Aquinas thus attempts to evade the intellectualist dilemma of the intellect necessitating the choice. In doing so, Aquinas attempts to break the causal chain that links back to God and thereby address the hard problem of the fall. Nevertheless, Aquinas invokes a voluntarist element and may not be a strict or pure intellectualist (Aquinas 2003: 168; Hoffman 2020: 213). To avoid regress about the will’s movement, Aquinas posits that God is the first mover of the will, which raises the question of how successfully he addresses the hard problem of the fall (ST I–II.9.6; Aquinas 1947).

To address the harder problem of the fall, Aquinas maintains that the volition is subjectively rational to the degree that the angel correctly regarded the good object as good and acted accordingly. However, Aquinas does not offer a contrastive explanation between the good and bad angels to explain why only some fell. Some did not fully consider God’s ordinance, and some did. Of those that didn’t, Aquinas only explains how these angels could act sinfully, not why some did. (For more on Aquinas’ view on sin, see McCluskey 2017.)

While the voluntarist position suffers from the question of intelligibility and mystery with the harder problem of the fall, the intellectualist position suffers from the question of determinism and placing causal responsibility on God’s side.

2.2 Adam and Eve

Contemporary and historic accounts of original sin posit that humanity originates from two historic individuals: Adam and Eve (Rea 2007; Couenhoven 2013: ch. 2; see Creation in the Old Testament). Some thinkers are open to the possibility that human beings originated from a historic community (e.g. Crisp 2019a). According to these traditional accounts, these individuals fell from grace by sinning early on and thus adversely affected their offspring (section 3).

William Lane Craig (2021: ch. 1) maintains that the historical Adam and Eve are theologically important for no fewer reasons than the doctrine of scriptural truthfulness and reliability and the doctrine of Christology. If the biblical text maintains and the authors mean to teach that there were two historic individuals, Adam and Eve, then a denial of these individuals would call into question the truthfulness of the text (cf. Paul in Rom 5). And if Christ himself believed in a historic Adam (cf. Matt 19:4–6), then a denial of Adam and Eve’s existence seems tantamount to claiming that God held a false belief.

Others deny the claim that there are two historic individuals from whom the remainder of humanity originates for scientific reasons. For example, Celia Deane-Drummond maintains that the story of Adam is a mythological account of God’s early creation of human beings, and is critical of the compatibility of traditional theological understandings with contemporary scientific findings (Deane-Drummond 2009). The deliverances of scientific disciplines seem to be – prima facie – jointly inconsistent with the claim that two historic individuals lived in a state of union and grace, though later fell and adversely affected humanity. Following Thomas McCall (2019), these deliverances are, first, there was death and predation before the fall. This is called the ‘red tooth thesis’. Second, humans share ancestry with other hominins – such as Neanderthals – and primates. This is called the ‘common ancestry thesis’. Third, and implied by the common ancestry thesis, that humans evolved as a sizable group. This is called the ‘large initial population thesis’.

Some contemporary thinkers who directly engage with the question of the fall and historical individuals in light of scientific concerns include S. Joshua Swamidass (2019); Daniel H. Spencer (2023); Daniel W. Houck (2020); and Gijsbert van den Brink (2020). There are at least three possible ways for the claim that there are two relatively recent historical individuals (or a community) who fell and from which the remainder of humanity originates to be jointly consistent with the above three scientific claims. Each of the following positions assumes that the above claims about human origins are true and does not dispute the red tooth thesis, the common ancestry thesis, or the large initial population thesis.

3.1 Pelagianism and original sin

Historically, the doctrine of original sin provided a basis for the claim that all human beings require Christ’s atoning work. Some contemporary thinkers affirm that original sin is important for providing this basis (Couenhoven 2016; McFarland 2016). Others deny this and instead affirm that individuals only stand in need of Christ’s atoning work for personal sin, and that personal sin is universal (Craig 2021; Torrance 2023).

The doctrine of original sin received its finer articulation in discussions between Augustine and Pelagius (McFarland 2016). Pelagius maintained that human beings retain a healthy amount of freedom to do good and evil, even after the fall of our ancestors. Similarly, Pelagius maintained that human beings are only responsible for – and therefore blameworthy and possibly punished for – freely committed personal sins. Personal sin occurs by imitating Adam’s example, according to Pelagius, but not because of an inherited constitutional fault. Furthermore, for reasons related to free will and responsibility, Pelagius’ position implies that no individual would necessarily fall into sin, though all certainly do fall into sin. (For more on this, see Woods 1882; McCall 2019: 280–300.)

As Augustine and the Council of Orange determined, Pelagius’ position implied that human beings can avoid sin by their efforts and not require Christ’s atoning work. Augustine’s silver bullet was to articulate the doctrine of original sin in conversation with scriptural passages such as Romans 5 and claim that each human being is congenitally sinful and inherits a constitutional fault. If so, all individuals require Christ’s atoning work.

3.2 Original sin as constitutional fault

Original sin is often thought of as a loss to or distortion of human nature, the origin of most actual sins, and a condition that inevitably leads to actual sin (Franks 2012; Crisp 2019a). According to Couenhoven, the core of Augustine’s doctrine of original sin is that all human beings (exceptions provided) have a constitutional fault (Couenhoven 2013: 46). The constitutional fault is often understood as a wayward disposition to commit personal sin, a corruption of one’s affections and intellect, and an improper functioning as human beings (Couenhoven 2013: 12, 30; McFarland 2016: 308).

There are two main ways to understand the constitutional fault. On the first view, the fault is a loss of an original grace, such as the grace of original righteousness or holiness. Anselm and Aquinas hold similar views, and this is the view of the Roman Catholic Church as enumerated in the Catechism (CCC 1997, para. 405; Houck 2020; MacDonald 2021). The loss of this original grace may include being subjected to ignorance, suffering, and death, and the inclination to sin. For Aquinas, the loss of the original grace includes physical infirmities as well as intellectual and moral deficiencies (ST I–II.85.3, 5; Aquinas 1947).

On the second view, a view more often associated with different Protestant thinkers, original sin is a type of perversion or moral corruption of human nature (McCall 2019: 159). John Calvin, for example, calls original sin a ‘[d]epravity of our nature’; we are ‘perverted and corrupted in all parts of our nature’ (Calvin 2008: 152). This corruption leads to personal sins, and it primarily consists of a tarnishing and staining of a once-pristine nature. In either case, the constitutional fault typically consists in a comparative clouding of the intellect and a weakness or distortion of the will.

The claim about an inherited constitutional fault is often accompanied by the further claim that human beings exhibit an objective moral guilt for exhibiting the constitutional fault. This is especially so within the Reformed tradition (Crisp 2019a: 145; Vorster 2022; Madueme 2021). However, one may maintain that humans inherit a constitutional fault from human ancestors without maintaining that all human beings have an original guilt, whether personal or alien. This trimmed-down version of original sin is commonly called the ‘corruption-only’ account; it is also called the ‘moderate version’ of original sin (Vainio 2021: 329). Contemporary supporters of this corruption-only view include, for example, Swinburne (1989); Crisp (2019a), McFarland (2010, 2016), McCall 2019), Wyma (2004), Plantinga (1974), and Loke (2022).

3.3 Constitutional fault and original guilt

The doctrine of original guilt builds upon the doctrine of original sin. Accordingly, this doctrine is sometimes called the ‘strong version’ of original sin. The doctrine of original guilt generally maintains that, in addition to suffering a corruption from the fall of our human ancestors, human beings are objectively guilty for Adam’s first sin (Vorster 2022; McCall 2019: 162).

This guilt transmitted to Adam’s offspring is either personal guilt or alien guilt. If it is personal guilt, individuals are guilty because they actually sinned in Adam, or as Adam. If it is alien guilt, individuals are guilty because Adam’s first sin is imputed to them as Adam’s progeny.

Personal guilt is often explained with recourse to realism. According to realism, an individual is responsible for Adam’s sin because the future individual sinned in or with Adam (see Rea 2007; McCall 2019; Crisp 2019b for an overview). Realism maintains that there is some real (non-fictive) connection to Adam and the remainder of humanity. This is either because each future human being is Adam, or because each human being belongs to a larger whole. This may be spelled out as a four-dimensionalist view, or a fission theory. Realism posits that the corruption – the identity with or participation of individuals with Adam – is a basis for the guilt. In this way, corruption precedes guilt. Proponents of this view include Augustine, Aquinas, and Jonathan Edwards.

Alien guilt is often explained with recourse to federalism. According to federalism, Adam is the head of humanity because of the foedus or covenant that God made with humanity in Adam. As with a king or queen whose actions affect the members of their country, so too would Adam’s fall affect the remainder of humanity. In contrast to realism, this view involves a legal fiction. God treats future individuals as if they had committed the act of sin and accordingly holds these individuals guilty for Adam’s primal sin. Federalism often posits that guilt is a basis for future individuals’ corruption, the corruption being the punishment for the imputed guilt (malum poenae). In this way, guilt precedes corruption. Proponents of this view include Madueme (2021); Leslie (2020); and Vorster (2022). For a historical articulation, see the 1689 Baptist Confession of Faith, Article 6.3.

There is a third and minority view: mediate guilt. Personal and alien guilt focus on the relationship of Adam’s progeny to Adam’s primal sin. The mediate view of guilt focuses on inheriting a corrupt human nature and humanity’s resultant responsibility for the effects of the primal sin. According to the mediate view of original guilt, individuals are not responsible for the primal sin personally or through imputation, but rather for inheriting a corrupt human nature adversely affected by Adam’s primal sin. For example, Henry Blocher reasons that individuals are guilty for the inherited corruption because it is voluntary to the degree the will acquires a sinful disposition (Blocher 1997: 127–128). Calvin also appears to maintain a mediate view when he maintains that infants, before committing personal sin, bring condemnation upon themselves for their own defects and not another’s (Calvin 2008: book 2, ch. 1, section 8).

Similar to – though crucially different from – mediate guilt, Ian McFarland maintains that individuals are born with sinful wills and are accountable for their will’s resistance to God. McFarland maintains that this idea renders it meaningful to speak of the need for and reception of forgiveness, even though individuals are not morally responsible and guilty for having caused the state of sin in which they are born (McFarland 2010: ch. 7). Similarly, as enumerated above in section 1.2.1, Couenhoven maintains that individuals are responsible for their deep selves. Couenhoven maintains that our deep selves are sinful and afflicted by sin, even if not wrought by oneself initially, and can deserve blame or punishment (Couenhoven 2009).

3.4 The inevitability of sin

With the exception of the Orthodox Church (cf. section 4), most individuals in the Christian tradition maintain that personal sin is inevitable because we inherit a sinful condition, a constitutional fault (Crisp 2019a: 150). The Council of Trent, for example, maintains that no one can avoid all acts of sin throughout their life, even venial (Tanner 2016: sections 5–6). This is not to say that any specific act is necessitated to be sinful in one’s lifetime. Rather, this is to say that due to original sin – that is, the inherited constitutional fault and corresponding propensity to sin – humans eventually sin at some point in life.

In contemporary literature, this claim is called the ‘inevitability of sin thesis’ (or ‘IT’). The inevitability of sin thesis has been formulated in different ways (Timpe 2023: 10; Haratine 2023: 4). For example, following the work of W. Paul Franks,

IT: Necessarily in a world tainted by original sin, (a) every human subsequent to Adam and Eve is born in a condition such that it is inevitable that she sin (given that she performs at least one morally significant action), but (b) it is not inevitable that she sin on any given occasion. (Franks 2012: 358)

Franks criticizes this view of the inevitability of sin as generating a contradiction when combined with a possible claim (Franks 2012: 359ff.). Given the necessity operator, IT would be true of all people in all possible circumstances. While improbable, an individual may commit only one morally significant act in their lifetime. For example, a young child who has recently reached the age of moral maturity may die after having committed their first and only morally significant action. According to IT, this specific act must be a sin (claim (a)), though the specific act cannot have been inevitable (claim (b)). Thus, when conjoined with the possibility that an individual dies after only having committed one morally significant act, it follows from IT that this act is both inevitable and not inevitable.

IT also appears to conflict with libertarian views of free will. When combined with the above assumption, IT would maintain that, possibly, a specific sinful act is necessitated. In contrast, libertarian views of free will tend to maintain no specific act of sin is necessitated. Kevin Timpe (2023: 19ff.) has challenged this line of reasoning. Timpe argues that IT is compatible with libertarian views of free will given other salient theological commitments. For example, one might be a source libertarian and maintain that one is ‘free’ and responsible for their present actions so long as those actions are the result of libertarian free past actions. This would be a case of virtue libertarianism, where a free action can determinately originate from one’s character as long as one’s character is the result of past free choices that involved alternate possibilities.

IT finds scriptural support in certain Pauline passages (especially Rom 2:1, 3; 3:23; 7:14–15, 17–18). Other scholars invoke 1 John 1:8 as evidence for IT (Vicens 2022). Spencer (2023) provides an overview of whether Paul subscribes to original sin in Romans 5 and the theological significance of Paul’s belief in original sin and unity with Adam, considerations adjacent to IT since scholars almost universally claim that the IT is rooted in original sin.

IT finds its primary theological motivation in the claim that all humans require Christ’s atoning work. For example, Vicens maintains that, ‘if some people were able to avoid sin completely, then they would not need salvation from it’ (Vicens 2022: 153). This sentiment is common. However, others have shown that, regardless of personal sin, the stain of original sin suffices to ensure that all humans require Christ’s atoning work (Franks 2012; Haratine 2023). If this is correct, the inevitability of sin thesis is more pressing for those allegorical accounts that deny original sin. (For more, see McCall 2019; Torrance 2023; Spencer 2023; Haratine 2025; for additional concerns over the inevitability of sin thesis and corruption-only accounts of original sin, see Visala and Vainio 2025.)

6.1 The extensional relationship

Many contemporary philosophers of religion and theologians often use the terms ‘sin’ and ‘moral wrongdoing’ interchangeably. To the degree that moral wrongdoing exclusively pertains to actions, treating the two concepts as coextensive at least assumes a substantive commitment that implies sins are only acts and not dispositions or states. However, adherents to the Christian theological tradition also generally hold that some states and dispositions can be sinful (cf. section 3). (For a critical discussion of whether and how the language of sin is not reducible to moral language, see McFadyen 2000: chs 1, 2, and 8.)

In discussing the relationship between sin and moral wrongdoing, one must distinguish between the ontological and criteriological questions (Dalferth 1984: 182). Regarding sin, the ontological question asks, ‘what is sin?’ The criteriological question asks, ‘what is sinful?’ or ‘how can we tell what is sin?’ More generally, an ontological question asks what the nature or definiens of some object is. A criteriological question asks how to classify and identify some object or activity. In Ingolf Dalferth’s words, the criteriological question asks, ‘what warrant do we have for claiming an action to be sinful?’ (Dalferth 1984: 179). One might say that one sins whenever one commits moral wrongdoing. In this case, moral wrongdoing would be a criterion of sin, but not define sin. Similarly, one might say that one is a scientist if one regularly conducts experiments in a laboratory. This would not define what it means to be a scientist but provide a criterion for identifying a scientist.

There are five possible answers to the criteriological question about sin’s extension in relation to moral wrongdoing (Dalferth 1984: 175; Ashfield 2021: 158):

1. Anti-moralism: sin and moral wrongdoing are disjoint; the presence of one implies the absence of the other.
2. Non-moralism: some sins and moral wrongdoings overlap. Neither is necessary nor sufficient for the other; some sins are moral wrongdoings, and other sins are not moral wrongdoings (and vice versa).
3. Equi-moralism: sin and moral wrongdoing are coextensive. Sin is moral wrongdoing, and moral wrongdoing is sin. Each one is necessary and sufficient for the other.
4. Sub-moralism: sin is a subset of moral wrongdoing. There are no sins that are not moral wrongdoing, but there are some moral faults that are not sins. Moral wrongdoing is necessary for sin.
5. Supra-moralism: moral wrongdoing belongs to the class of sin. All moral faults are sins, though some sins are not moral faults. Moral wrongdoing is sufficient for sin.

In contemporary and historical theology, equi-moralism is the dominant position. Augustine and many medievals defined sin as moral evil, and any other evils as malum poenae (section 3.3). Medieval thinkers considered malum poenae to be such because the evils that afflict human beings are due to the fall and are akin to the just punishment of rational creatures.

In contemporary theology and philosophy of religion, the category of malum poenae is updated to the category of natural evil, a category that encompasses all non-moral evils. For example, Alvin Plantinga defines sin as moral evil, and other evils as natural evil (Plantinga 1974: 166). In a recent Cambridge Elements volume on the problem of evil, Michael Tooley never uses the term ‘sin’ and instead characterizes all presumable candidates for sin as moral evils (Tooley 2019). Similarly, in a companion to philosophy of religion, Philip Quinn maintains that sin and moral fault are interchangeable (Quinn 2010: 614). Sin and moral wrongdoing are often used interchangeably in much of contemporary theological literature. This use assumes either sub-moralism or equi-moralism, though sub-moralism is rare. (See Ashfield 2021: 158–162 for a list of some adherents to the above positions.)

Equi-moralism consists of two extensional claim:

1. Moral Necessity: moral fault is necessary for sin to obtain; and
2. Moral Sufficiency: moral fault is sufficient for sin to obtain. (Ashfield 2021: 158)

This distinction parses the above criteriological positions. Except for non-moralism and anti-moralism (the latter of which has few if any contemporary adherents), each position involves either moral necessity or moral sufficiency. Supra-moralism involves the moral sufficiency thesis, while sub-moralism involves the moral necessity thesis. Equi-moralism maintains both. Mike Ashfield (2021) calls this the ‘moral consensus’.

6.2 Problems for the moral consensus

Ashfield poses four problems for the moral consensus. Not all problems equally afflict each position within the moral consensus, and not all problems target all types of sin (e.g. actions versus states such as dispositions or attitudes).

The first problem is that of moral over-demandingness. Some of Christ’s commands, such as turning the cheek, intuitively go beyond the normal call of moral duty – they are supererogatory actions (Matt 5:38–48). Suppose one fails to obey this command. The moral necessity thesis would dictate that the scope of morally required actions is larger than intuitively considered to include inactions. This would pose a problem for equi-moralism and sub-moralism. Further, suppose that punishing such a sinful omission is not sinful. According to moral sufficiency, it would be morally permissible to sanction such omissions. This is only a problem for supra-moralism and equi-moralism. In either case, these revisions seem to make prominent normative ethical theories too demanding.

The second problem is that of agential unfairness. Suppose that certain cognitive and conative attitudes are sinful. A cognitive attitude might be the state of unbelief in God that possibly corresponds to hard-heartedness (Heb 3:8–16). A conative attitude might be the intentions and attitude of one’s heart, for example, to commit adultery or have hatred towards an individual (Matt 15:18–28). Though these attitudes are not apparently always within one’s direct voluntary control, Christ seems to call these attitudes sinful. In the case of lust, Christ claims that they are on par with the action. However, these attitudes do not seem to be moral faults; much less do they seem morally commensurate with the intended action. According to the moral necessity thesis, these biblical injunctions require one to be morally responsible for attitudes outside of one’s direct voluntary control. This violates the ‘moral-ought-implies-can’ principle, a principle that roughly maintains an agent is under a moral obligation to complete some action only if that agent has it within their power to complete that action. This is a problem for equi-moralism and sub-moralism. Similar to above, if sanctioning these attitudes is not sinful, then on supra-moralism and equi-moralism, these sanctions are morally permissible. If fairness to agents rests upon a respect for the ‘moral-ought-implies-(direct-)can’ principle, this results in a problem of agential unfairness.

A third problem is that of moral repugnance. This arises given that some biblical depictions of sin and injunctions against sin involve sins that are non-voluntarily or non-knowingly committed. For example, certain physical conditions, such as menstruation or leprosy, render one ritually impure (Lev 12–14). However, the relationship between the categories of ritual impurities, moral impurities, and sin is vexed (Ashfield 2021: 161–165, 167; Sklar 2008; Lam 2018). Nevertheless, to the degree that certain ritual impurities or a non-voluntary and non-knowing failure to observe requirements surrounding ritual impurities constituted sin, then the moral necessitarians would face a further challenge of subscribing to morally repugnant commands. According to the moral sufficiency thesis, if sanctioning these ritually impure states or failures to adhere to such practices is not sinful, then these sanctions are morally permissible.

The fourth problem is that of moral atrocity. The Old Testament contains sanctions for certain activities, such as idol worship, certain incestual relationships, consensual homosexual sex, and dishonouring of parents. In Leviticus, these activities merit capital punishment by stoning (Lev 18–20). Ashfield argues that the end of Leviticus strongly implies that failing to deliver these sanctions is sinful (Ashfield 2021: 169; cf. Lev 26:14–39). If this is the case, then moral necessity implies that failure to put these individuals to death is wrong. This is a problem for equi-moralism and sub-moralism. Furthermore, if obeying and delivering the sanctions is not sinful, moral sufficiency implies that one can deliver these sanctions without moral fault. This is a concern for supra-moralism. Similar issues arise when considering God’s apparent command to the Israelites to commit genocide when conquering the land of Canaan (Deut 20:16–18). For possible responses to these challenges, see Murray and Rea (2011) and Ashfield (2021: 170ff).