Almost everyone concludes that nobody is perfect and perhaps even that nothing is perfect. This is a standard excuse for human lapses or for quirks within nature, as well as for more laudable expressions of humility and finitude. So, writing a book about human perfection does indeed seem stupid – pretentious and ideologically naive. Worse still, perfectionism is often seen today just as a trait of the obsessional – a feature of madness.

Stupid, that is, until it is noticed that the claim that no body or thing is perfect itself assumes some notion of perfection (actual, aspirational or just theoretical).

It might also be noticed that claims about perfection are regularly made both about mundane matters – such as a perfect weekend – about flippant matters – such as a perfect nuisance – and about profound matters – such as a perfect death (albeit with changing historical perceptions of what constitutes a perfect death) – or sinisterly – such as a perfect murder (a murder that is perfect only for the murderer because it is undetectable). And perfect marks in an examination, once thought possible only in tightly defined areas such as elementary mathematical or linguistic tests, are now given more quirkily, say, in gymnastic events and TV dancing competitions.

It might even be claimed – as this book will argue – that a quest or aspiration for perfection is a defining characteristic of human beings, distinguishing us from other mammals – homo perfectus in preference to other claimants such as homo rationalis, a philosophical favourite and, more teasingly, Huizinga’s homo ludens.

Monotheists often claim that no body or thing is perfect except God, but then might be embarrassed about identifying God as a ‘body’ or a ‘thing’.

Christians often claim – following Hebrews 2.10 and 5.9 – that the only earthly person who was perfect is Jesus, but then might puzzle about how perfect was Jesus’ knowledge, say, of quantum physics or of the novels of J. K. Rowling.

And philosophers might conclude, without reading any further, that I have swallowed Anselm’s or Paley’s ‘proofs’ of the existence of God whole (emphatically, I have not).

Yet Christians might also recall that at the heart of the Sermon on the Mount is the extraordinary command for the followers of Jesus to ‘Be perfect, therefore, as your heavenly Father is perfect’ (Matt. 5.48) – something that I simply skimmed over in my previous book, Moral Passion and Christian Ethics (2017), within this ongoing Cambridge series, New Studies in Christian Ethics. How does that crucial verse square with a Christian conviction about ubiquitous human sinfulness?

This particular text is going to feature regularly throughout this book and is examined in depth in Chapter 5, but it is worth noting at the outset that it has deeply divided theologians in the past. In descending order of dates, John and Charles Wesley, John Calvin, Thomas Aquinas, Augustine of Hippo, Gregory of Nyssa and Tertullian offered very different interpretations of Matt. 5.48, with the Wesley brothers being enthusiastic, Calvin condescending, Aquinas subtle and nuanced, Augustine limited, Gregory surprisingly relativistic and Tertullian just polemical. Each showed clearly the influence of both their particular social contexts and their radically different theological takes on humanity.

John Wesley’s response is closely related to his radical call for personal holiness. In the first volume of his collected sermons, he cited Matt. 5.48 eight times and always positively. The following conclusion to a sermon that he gave on the Sermon on the Mount in Matt. 5–7, is the most striking with the link that he made between a call to holiness (as in 1 Pet. 1.15) and a call to perfection (as in Matt. 5.48):

There are no reservations or nuances here – secular or theological [see Noble Reference Noble2013]– about this call to perfection expected from the followers of Jesus, but it does require watchfulness, prayer, belief, love and striving on their part. This call is emphatically reinforced in many of his brother’s hymns. Just consider the following examples from Charles Wesley [Wesley Reference Wesley1933]:

• O for a heart to praise my God: there is a longing for ‘a heart from sin set free … where only Christ is heard to speak … a humble, lowly contrite heart, believing, true, and clean … and full of love divine; perfect, and right, and pure, and good, a copy, Lord of thine’.

• Christ, whose glory fills the skies: ‘Visit then this soul of mine, pierce the gloom of sin and grief; fill me radiancy divine, scatter all my unbelief; more and more thyself display, shining to the perfect day.’

• Author of life divine: ‘Our needy souls sustain, with fresh supplies of love, till all thy life we gain, and all thy fullness prove, and, strengthened by thy perfect grace, behold without a veil thy face.’

• O thou who camest from above: ‘Ready for all thy perfect will, my acts of faith and love repeat, till death thy endless mercies seal, and make my sacrifice complete.’ And, most majestically, in the final verse of

• Love divine, all loves excelling: ‘Finish then thy new creation, pure and spotless let us be; Let us see thy great salvation, perfectly restored in thee, changed from glory into glory, till in heaven we take our place, till we cast our crowns before thee, lost in wonder, love, and praise!’

In a more reflective mode, John Wesley, remarkably, came to ‘retract several expressions in our Hymns, that partly express, partly imply … the impossibility of falling out from perfection’, arguing, instead, that: ‘There is such a thing as perfection’ during the lifetime of a human being; but, ‘It is not absolute. Absolute perfection belongs not to man, not to angels, but to God alone’; ‘It does not make a man infallible’; ‘It is improvable … one perfected in love may grow in grace’; and ‘It is constantly both preceded and followed by gradual work’ [Wesley Reference Wesley1777]. In his wide-ranging survey of perfectionist theology, Anthony Baker, perhaps too harshly, concludes that in this way Wesley simply ‘dismantles his own account of perfection’ [Baker Reference Baker2011, 283].

In contrast, Calvin clearly had reservations about any straightforward adoption of Matt. 5.48. Preceding his brief and grudging interpretation of this text, he noted caustically that monks ‘and other bawlers of the same class … were not ashamed to claim perfection for themselves’ [Calvin Reference Calvin1875, 305]. He then interpreted the Matthean text as follows:

The qualifying words here are obvious – ‘solely’, ‘resemblance’, ‘should it be preferable’ and ‘more clearly from the words of Luke’ – and suggest that Calvin was theologically uncomfortable with the notion of human perfection and more comfortable with the command to be merciful (a judgement quite opposite to that of textual critics today who tend to regard an uncomfortable variant reading as most likely to be original, on the grounds that it is difficult to see why a later scribe would want to make a comfortable reading uncomfortable). Calvin’s strong notion of predestined human sinfulness and corruption weighed too heavily against any straightforward adoption of Matt. 5.48. Even today, The Oxford Encyclopedia of the Bible and Ethics has no separate entry for ‘perfection’ in its two volumes, despite noting in passing that, within Matthew at least, it is ‘an important key-word’ [Brawley Reference Brawley2014 Vol. 2, 21].

More positively, Calvin did offer a dynamic understanding both in his understanding of God’s perfection – involving acts of ‘free and pure kindness’ – and in humans who ‘aim at the same object’. This is not unimportant. In classical Latin, the adjective perfectus does have the dynamic meanings of ‘a finishing’ or ‘a completing’ [Lewis and Short Reference Lewis and Short1958], albeit with static meanings predominating in the classical Greek adjective teleios, such as ‘full-grown’, ‘accomplished’, ‘unblemished’, ‘complete’, ‘finished’ and ‘fulfilled’ [Diggle Reference Diggle2021]. In biblical Hebrew tamim or salem (which the Septuagint translates as teleios) has similar predominantly static meanings of ‘blameless’, ‘unblemished’, ‘undivided’ or ‘whole’ [Davies and Allison Reference Davies and Allison1988, 560–1], as does the equivalent Arabic word tamm in the Qur’an.

In contrast again, Aquinas was comfortable with Matt. 5.48, but, characteristically, he made careful and lengthy distinctions (some static and some dynamic) beyond the text itself, on the basis of both rational thought and his observations about human nature.

Using the method of opposing questions and detailed responses adopted throughout Summa Theologica, he noted at the outset a clash between the standard aphorism that ‘no one can be perfect in this life’ and the Matthean command to perfection, from which ‘it seems that one can be perfect in this life’ [videtur quod aliquis in hac vita possit esse perfectus]. Then he responded as follows:

It is the third group of these distinctions that characterises earthly human perfection for Aquinas. Some, at least, of the classical meanings (both static and dynamic) of perfectus, teleios and tamim – such as blameless, unblemished, completing or full-grown – do seem to match this group. To this he then added ways that these distinctions can relate more specifically to the Dominical Command of neighbour-love:

These distinctions bring more clarity than those of the Wesley brothers or Calvin, with links both to Wesleyan holiness and to Calvinist dynamism, and they also go beyond Augustine who, in his On the Sermon on the Mount, related Matt. 5.48 solely to enemy-love:

Yet Aquinas’ distinctions still need to be tested carefully. Much of the rest of this important section in Summa Theologica acts (unintentionally) as a warning to the modern reader that Aquinas’ teaching needs to be contextualised and appropriated selectively – especially the part that discusses ‘whether prelates and religious are in the same state of perfection’. Here Aquinas’ assumptions about human perfection become decidedly hierarchical, clerical and medieval.

There is already a creator/creature hierarchy of perfection in the Aquinas passages just quoted and it is probably inescapable in some form for a monotheist. Yet even within this hierarchy there were, for Aquinas, different levels of perfection, in this order: God, angels, resurrected humans [in patria] and then earthly humans [in via]. But even within that last group [in via], bishops and monastics are placed at a higher level – albeit differently from each other, with bishops more focused upon pastoral care (perhaps a more appropriate translation of caritas than ‘charity’ today) and monastics upon prayer and contemplation – from other earthly humans. As a monastic himself, Aquinas saw a ‘beatific vision’, which he is said to have experienced towards the end of his life and perhaps Paul reported in 2 Cor. 12.1–4 as the aim of contemplation.

In passing, Aquinas admitted that clerics did not always live up to their expected level of perfection – like Chaucer and, later, Luther and Calvin, Aquinas was aware of clerical abuse, just as we are today. But, by such abuse, he argued, they were negating their expected perfection (similar, perhaps, to the Synoptic Jesus’ judgement of leading Pharisees). Nonetheless, for Aquinas, when clerics acted properly, they represented a higher level of perfection than other earthly humans, just as resurrected humans did (following Augustine in Book XXII of City of God) when compared with earthly humans. There are disturbing elements here of another hierarchy that Aquinas assumed, namely: that men are more rational than women; women are more rational than slaves; and slaves are more rational than animals – with only God deemed to be supremely rational.

Perhaps the fourth-century Gregory of Nyssa’s relativistic take on Matt. 5.48 helps somewhat:

Nevertheless, elsewhere, qualifying this somewhat, he also held that ‘perfection consists in our never stopping in our growth, never circumscribing our perfection by any limitation’ [Gregory Reference Jaeger, Cavarnos and Gallahan Woods1953 8.1, 213–14]. In contrast, each persona within the Trinity, he insisted, ‘is perfect in all respects’ and without any ‘excess or deficiency’ [Raddle-Gallwitz Reference Raddle-Gallwitz2017, 276].

Tertullian, writing against Marcion in the early third century, however, is decidedly unhelpful. He takes Matt. 5.48 (which he quotes inexactly) as being an opportunity to insist that ‘Marcion’s God is imperfect in goodness on the ground that there is perdition … [Marcion’s followers] are saved as far as their soul, but forsaken in their body, which according to Marcion, does not rise again’ [Raddle-Gallwitz Reference Raddle-Gallwitz2017, 51].

An additional problem in following Aquinas too closely today relates to his pre-scientific views of human perfection within the Garden of Eden. Patrick Clark’s fine, albeit committedly Thomist, analysis Perfection in Death has a section on ‘Prelapsarian Virtue and Human Perfection’, which he argues has been underappreciated recently [Clark Reference Clark2015, 139–42]. He quotes, without dissent, this passage from Aquinas:

A literal belief in Adam delivers yet another layer of human perfection, albeit one that is lower than someone who ‘will sacrifice for his neighbour, but [also] bodily suffering and even death’ – that is, lower than ‘perfection in death’, which, Clark argues, is especially manifest in the Christian martyr. Yet, for those Christians who cannot accept any literal belief in the Garden of Eden, in Adam or in his (and, as a result, our) Fall, this presents a considerable problem. In addition, there was even a problem for Aquinas, since he glossed over his obvious difference here from Augustine’s somewhat embarrassed speculations about how Adam and Eve might have produced children virtuously before the Fall without having lust-driven sexual intercourse [City of God, XIV, 26].

My own position, having had a neo-Thomist, the clever and holy Eric Mascall, as my doctoral supervisor half a century ago, is that I continue to learn from the genius Aquinas (for me, the ‘perfect’ theologian), as, indeed, do other Anglican moral theologians today [Sedgwick Reference Sedgwick2019, 117–19], but I do not feel bound by all his medieval assumptions. I have, however, been spurred on to engage more directly with Aquinas in this study by Esther Reed’s very thoughtful review of my Moral Passion and Christian Ethics, in which she concludes that:

It would be thoroughly over-indulgent to repeat points made before, going over the same territory so soon again here. Yet on re-reading my previous text with Esther Reed’s critique in mind, it has become obvious that it started and finished with an insight from the late Dominican Servais Pinckaers’ classic Passions and the Virtue (Reference Pinckaers2015) – that moral passion can be mapped on different moments in the moral life, of which the most mature is perfection. Shamefully, I had sheltered behind Pinckaers (and he behind Augustine and Aquinas). Reed is right. More primary work is needed. Hence this present book.

Gregory, Aquinas, Calvin and the Wesley brothers might have agreed that human perfection is rare and requires considerable effort – with Calvin concluding that it is finally beyond fallen humanity’s capacity to attain and with Gregory suggesting that it is only partially so. The Wesleys, Aquinas and Gregory linked human perfection to holiness, whether in the form of a ‘beatific vision’ or of us being ‘changed from glory into glory’ – the latter being akin to the highly aspirational doctrine of theösis derived, at length first by Cyril in the fifth century from 2 Pet. 1.4 of humans becoming ‘participants in the divine nature’, then defined famously by Dionysius in the sixth century as ‘the attaining of likeness to God and union with him as far as possible’, and amplified further by Maximus and others in the seventh century, with theösis seen variously either as a ‘transformation of humanity in principle as a consequence of the Incarnation’ or as ‘the ascent of the soul through the practice of virtue’ [Russell Reference Russell2004, 14 and Torrance Reference Torrance2020 and Reference Torrance, Chryssavgis and Gallaher2021]. This doctrine in either broad form was, and remains, popular in Eastern Christianity, but it can also be detected implicitly in Ambrose [Raddle-Gallwitz Reference Raddle-Gallwitz2017, 265]. Within recent Western theology, theösis is explicitly identified as ‘a key theme’ in Keith Ward’s Sharing in the Divine Nature and is understood by him as ‘the inclusion of all things in Christ’ [Ward Reference Ward2020, 19], and it is also foundational to Anthony Baker’s more oppositional (his term is ‘diagonal’) study [Baker Reference Baker2011].

With or without a formal doctrine of theösis, Gregory, Aquinas, Calvin and the Wesley brothers all saw human perfection in dynamic terms, as a ‘becoming’ – with Aquinas making a crucial distinction between God’s (comparatively static) perfection as being integral, essential (ontological) and ‘in full capacity’ and human perfection, resulting rather from an absence in an exceptional person ‘of everything incompatible with caritas’ (i.e., unblemished or blameless) and, more positively, of a person demonstrating active caritas and/or spiritual neighbour-love.

This Book’s Contents

The chapters that follow explore these features in greater depth, in order to give shape to a critical concept of perfection. But how is ‘perfection’ to be defined in so many different contexts? As seen already, Aquinas used Aristotle’s universal definition, namely: ‘That is perfect to which nothing is lacking.’ This might fit perfect scores in competitive gymnastics or exams in elementary mathematics or language translation, resulting from no observable faults, but little else. In less absolutist terms, this definition might be modified to: ‘That is perfect to which nothing is thought to be lacking’, or, in more evaluative, dynamic and contextual terms: ‘A perfect action or artefact is one where it is difficult to see how, in its context, it could have been done better.’ The latter is the initial, working definition of ‘perfection’ used to test the various examples explored in Part II, with a more specifically Christian understanding of human perfection emerging in Parts II and III related to the perfection of Jesus Christ, perceived especially at the Transfiguration.