Newman, Chesterton, ‘Idea’, and Worldview

In An Essay on the Development of Doctrine, Newman describes Christianity as ‘an idea’. He explains what he means by this as follows: ‘The idea which represents an object or supposed object is commensurate with the sum total of its possible aspects, however they may vary in the separate consciousness of individuals; and in proportion to the variety of aspects under which it presents itself to various minds is its force and depth, and the argument for its reality’.Footnote ⁶ In shaping his argument thus he steps away from discussion of individual doctrines in the context of systematic theology and moves towards considering Christianity as a whole, considering together ‘the sum total’ of all ‘possible aspects’ of the Christian religion as a whole, not only theology. This integrative and totalizing approach paves the way for the consideration of Christianity as a worldview: if Christianity can be discussed and pictured as a totality, as a complex, composite ‘idea’ which includes social, cultural, historical, theological, spiritual, philosophical, and other aspects in one unified entity, then that unified whole implies a worldview, because the view from such an integrated, holistic totality could be nothing less than a worldview. To use a simple image, if Christianity as a whole may be pictured as an ‘idea’, then the perspective on life as viewed from that ‘idea’ can only be a Christian worldview.

This holistic presentation of Christianity is evident again when Newman writes of giving ‘an interpretation to the course of things’, of the importance of ‘the voice of mankind, and the course of the world, that is, of human life and human affairs’, in ‘acquiring’ the knowledge of God, and of the need to ‘test, interpret, and correct’ what ‘the universal testimony of mankind … the history of society and the world’ present ‘to us for belief’.Footnote ⁷ The implications of this approach are profound. One major implication is methodological: the Christian apologist should address all these areas rather than restricting himself or herself to the defence of particular doctrines. This constitutes a remarkably extensive agenda for apologetics, one which leads the apologist far from the defensive posture and strictly theological focus of much conventional apologetics, out to engage with diverse fields of knowledge, intellectual, cultural, historical, literary, socio-political, and other. Did Chesterton, in his apologetics, follow Newman's lead in addressing ‘the course of the world … of human life and human affairs’, testing and interpreting ‘the history of society and the world’, and engaging with the ‘voice’ and the ‘universal testimony’ of humankind? Does his methodology as an apologist include a similarly ‘big picture’ approach, one which addresses Christianity in terms of (what would today be seen as) worldview?

Consider Chesterton's article, ‘The Return of the Angels’, in the Daily News of 14^th March, 1903: this article is probably the closest he came to outlining his overall approach to apologetics. In this article, he claims to be adopting the scientific ‘method of the hypothesis’. He explains this method thus: ‘It can be most clearly and simply conveyed in common language by saying that it is the principle that the best way to see if a coat fits a man is not to measure both of them, but to try it on. It is the replacing of the very slow, logical method of accumulating, point by point, an absolute proof by a rapid, experimental and imaginative method which gives us, long before we can get absolute proof, a very good working belief’. He suggests that the best way to test a ‘theory about the universe’ is to ‘assume it to be true’ and assess the results of proceeding on that assumption:

In other words, he is arguing that when Christianity is tested by the ‘method of the hypothesis’ it provides a convincing and satisfying explanation of our lives and experiences: the ‘spiritual theory’ of Christianity ‘rests … on the fact that the thing works out. We put on the theory, like a magic hat, and history becomes translucent like a house of glass’;Footnote ⁸ in Chesterton's view, it explains human experience, history, and culture. This is the method he went on to employ throughout much of his work. Where Newman talks of Christianity as an ‘idea’, Chesterton applies that totalizing concept to apologetics and uses the ‘method of the hypothesis’ to attempt to demonstrate that Christianity, taken as a complete ‘spiritual theory’, is able to offer a more satisfactory explanation of human history and experience than its rivals; in modern terms, both are presenting Christianity as a worldview.Footnote ⁹

This sets up the framework of Chesterton's apologetics: in Newman's terms, he makes ‘the sum total’ of Christianity's ‘possible aspects’ the field of his discussions. That ‘sum total’ is consistently made the measure of all other philosophies, ideologies, and philosophies in Chesterton's work. He presents the ability to encompass all that is entailed in being human as a test for any belief system: not so much asking questions about divine authority or the supernatural, but asking if that belief system is sufficient to provide a home for all that is human. Thus, he judges Theosophy and other ‘modern attempts at Syncretism’ unfavourably because ‘They are never able to make something larger than the Creed without leaving something out. I do not mean leaving out something divine but something human; the flag or the inn or the boy's tale of battle or the hedge at the end of the field.’Footnote ¹⁰ The Christian creeds, of course, do not literally refer to flags, inns, boys’ tales of battles, or hedges at ends of fields. He uses these images to stand for a larger vision of humanity, which he believes is implied by Christian doctrine, and claims that Christianity offers more than other ideologies, philosophies, or religions, both at the social and cultural level – in terms of leading to human fulfilment and flourishing – and, in more directly theological and philosophical terms, in what, for example, it can reveal about meaning and purpose.

Chesterton follows the same approach in Orthodoxy. In his introduction to that book, he writes that it will discuss ‘the actual fact that the central Christian theology (sufficiently summarized in the Apostles’ Creed) is the best root of energy and sound ethics’.Footnote ¹¹ He does not, at this point in his narrative, assert that ‘the central Christian theology’ is true, or even mention what it includes. Rather than analyse the content or truth value of that ‘central Christian theology’, he discusses the effects of a set of ideas in human experience. That means he can claim as an ‘actual fact’ that Christian theology produces measurable, positive results in human life, a claim that makes the results produced by that theology, in terms of ‘energy and sound ethics’, a kind of experimental test of it, as if the concepts of Christian theology were points on a theological compass, and the reader is asked to see what direction such a compass might give. Similarly, in 1903, when asked why he was a Christian, Chesterton replied, in his column in the Daily News: ‘Because I believe life to be logical and workable with these beliefs and illogical and unworkable without them’.Footnote ¹² Again, he applies the test of experience and affirms the explanatory power of Christianity, its ability to give ‘an interpretation to the course of things’, in Newman's terms.

This dimension of his methodology as an apologist can clearly be seen throughout Chesterton's work. For instance, in What's Wrong with the World, even though he states that ‘This book must avoid religion’,Footnote ¹³ he nevertheless asks the reader to try the experiment of imagining what would happen if Christ were made society's guide to social progress. It as if he suggests that society might steer itself by a theological compass oriented around the human figure of Christ. Chesterton suggests that in order to have social progress, it is necessary to have ‘a permanent human ideal’ and proposes Jesus Christ as that ideal, promising: ‘in dealing with this, I will try to be as little transcendental as is consistent with reason’.Footnote ¹⁴ Then, in the rest of the book, he suggests what social effects might follow from taking Christ, not as God incarnate, not as saviour and lord, but as that ‘permanent human ideal’. By putting his argument in terms of ‘actual fact’ and experience, rather than in terms of truth or revelation, he keeps the discussion at the level of what can be measured and observed in human experience rather than making claims involving metaphysics or religious authority; he makes, in Newman's terms, ‘the course of things’, ‘the voice of mankind, and the course of the world, that is, of human life and human affairs’ the field of operations of his apologetics, rather than defending specific doctrines.Footnote ¹⁵

Inter-disciplinary Apologetics

Secondly, let us reflect on the inter-disciplinary nature of Newman's methodology as an apologist: the close relationship between literature, history, culture, and theology in his work is well-known. For instance, the Essay on Development intertwines history and theology from beginning to end.Footnote ¹⁶ This close nexus of the theological and the historical means that Newman's view of history goes far beyond the boundaries of what would be generally accepted in the academic study of history. This is exemplified by his assertion, in 1841, that ‘The Christian history is “an outward visible sign of an inward spiritual grace:” … Christianity has an external aspect and an internal; it is human without, divine within. To attempt to touch the human element without handling also the divine, we may fairly deem unreal, extravagant, and sophistical; we may feel the two to be one integral whole, differing merely in aspect, not in fact. … All that is seen, – the world, the Bible, the Church, the civil polity, and man himself, – are types, and, in their degree and place, representatives and organs of an unseen world, truer and higher than themselves’.Footnote ¹⁷ It is an essentially sacramental view of history, and one that expresses a Catholic and Christian worldview, while being incompatible with any secular frame of thinking; it illustrates the correctness of Ker's judgement that Newman saw ‘theological enquiry … as inseparable from the study of history’.Footnote ¹⁸

The depth of the integration of theology with philosophy and culture in Newman's thinking can be illustrated by the curious case of Matthew Arnold. Arnold is often seen as the ‘prophet of culture’, culture, that is, as more or less a replacement for religion. Yet he wrote to Newman, in 1868, of ‘your influence and writings … the impression of which is so profound, and so mixed up with all that is most essential in what I do and say’. In 1871, in another letter, Arnold insisted: ‘In all the conflicts I have with modern Liberalism and Dissent … I recognize your work’. He explains a little concerning Newman's influence when he writes, in that second letter: ‘nothing can ever do away the effect you have produced upon me, for it consists in a general disposition of mind rather than in a particular set of ideas’.Footnote ¹⁹ Newman's cultural criticism was so bound up with his theological and philosophical writing that Matthew Arnold, although departing from Newman theologically, remained his declared disciple in his philosophical and cultural ‘general disposition of mind’. This demonstrates the extent to which the cultural, the philosophical, the literary, and the historical are bound up with the theological in Newman's work. Can something of the same relationship between theology, philosophy, culture, literature, and history be seen in Chesterton's work?

Consider the article ‘Why I am a Catholic,’ in The Thing: in this article, Chesterton does not rely on theological argument but claims that ‘historical proofs’ speak for Catholic Christianity and against its rivals. He argues that historical evidence, ‘true historical cases’, will vindicate his theological position and disprove his opponents’. In the same article he demonstrates how inter-disciplinary his apologetics is by supporting his theological position with reference to ‘human and personal proofs’, to ‘the colour and poetry and popularity of religion’, and to ‘the deepest lessons of practical psychology’. In short, he manages to provide an explanation for his own Catholicism which avoids metaphysical questions, to a great extent, keeping his account largely at the level of ‘the course of the world’ and the ‘voice of mankind’.

Chesterton's approach to his opponents in debate, here and elsewhere, also puts into practice Newman's guidance about the need to ‘test, interpret, and correct’ what ‘the universal testimony of mankind … the history of society and the world’ present ‘to us for belief’. Chesterton does that testing, interpreting, and correcting with great relish. The example above is typical of his habit of combining an inter-disciplinary critique of other philosophies and religions with an equally inter-disciplinary presentation of a Catholic Christian alternative; negative criticism of others’ views is married to a positive presentation of his own. A Short History of England is a characteristic example: the book combines two kinds of analysis into one narrative: a critique of the Whig theory of English history, which saw the move from Catholicism to Protestantism as part of a story of progress culminating in a secular society; and a contrasting argument for a Catholic and Christian version of English history. In this book, the two analyses are embedded in the narrative itself.Footnote ²⁰ In another analysis of history, Chesterton argues:

Characteristically, he is not so much concerned with the overall historical picture as with the role of Catholic Christianity in a given historical context, and also with attacking the Whig interpretation of history and other historical schemes which depict the rise of secularism and the decline of religion as progress.

There are endless other examples of his habit of combining theological investigations with help from a range of other disciplines. In The Everlasting Man, for instance, his interpretation of comparative religion works on the basis of the analysis of human experience and of psychology: rather than divide religions geographically, he divides religion ‘psychologically … into the strata of spiritual elements and influences that could sometimes exist in the same country, or even in the same man. … I believe some such classification will help us to sort out the spiritual experiences of men much more successfully than the conventional business of comparing religions’.Footnote ²² Characteristically, he here seeks to analyse religious history and religious experience to see if his particular theological theories enable a better understanding of ‘the spiritual experiences of men’ – once again he makes human experience the test of his theology.

The breadth of his approach means that it does not entirely rely on theological debate, nor is it individualistic. He does not see apologetics only in terms of individual thinkers grappling with different arguments; instead, he is very aware of its communal and social dimensions. For instance, he questions the ideologies that might seek to replace religion in a secular future, asking what social cohesion they could achieve:

Chesterton here, typically, argues about how well belief systems work in practice, not just discussing theoretical truth, but also actual cultural and ethical effects. He makes that argument at a social, not an individual, level, testing different schools of thought by their effects on communal life. This social and communal dimension broadens his apologetics considerably.

When Chesterton writes, ‘The historic advantage of religion was that it made every part of a man's life, art and ethics and the rest, dependent upon a general view of life itself’,Footnote ²⁴ this formulation places religion (and, by implication, theology) at the heart of a multi-disciplinary understanding of ‘every part’ of life, including ‘art and ethics and the rest’. Here, as so often, Chesterton positions theology as a close partner of historical and literary studies and other intellectual disciplines. Examples might be cited from many books and essays: perhaps the most sustained application of his theological analysis of history came in The Everlasting Man and A Short History of England; his theological interpretation of culture can be seen particularly clearly in his biographies, of Watts, Dickens, and others; his theological understanding of human experience in the Father Brown stories and his other fiction,Footnote ²⁵ and in his Autobiography. This inter-disciplinary approach is itself very well suited to Chesterton's worldview apologetics, because the different disciplines he involves in his work multiply the number of different ‘converging probabilities’ he can create to point towards validation of a Christian worldview.

These examples show how Chesterton tries in his Christian apologetics to deconstruct the arguments and narratives of other belief systems and tell what he considers to be a better and more accurate story with regard to historical progress and the role of Christianity in history. He combines theological with historical, cultural, and philosophical arguments to analyse human experience, history, and culture, not just to support a Christian worldview, but also to dissect and deconstruct the claims of alternative worldviews. He consistently uses theology in combination with other disciplines for the analysis of human experience, culture and history.

Chesterton's treatment of his own theology underlies the inter-disciplinary nature of his work: he refers to theology, in combination with other disciplines, to give direction to his discussions. He consistently uses the ideas that form his architecture of meaning, the framework of his theology, as reference points in his work, as if they were, so to speak, the points of a ‘theological compass’. He sets these ideas as hypotheses before his readers to consider what value they have as guides to life, by seeing what effects and what explanatory power they may have in human culture, history, and experience generally, outside a specifically religious context. Each time this ‘theological compass’ appears in different arguments and narratives it points towards validation of aspects of a Christian worldview, thus providing, on each occasion it appears, another of those ‘converging probabilities’ of which Newman wrote, converging from the different contexts of Chesterton's writing to create a pattern of evidence in favour of a Christian worldview. Rather than argue over untestable truth claims he refers to testable human experience. He regularly asks, of his own and other belief systems, not just ‘Is it true?’ but ‘Does it work?’ His analysis is directed very often towards the practical effects of Christian and other ideas, not just their theoretical truth. In all this he reflects Newman's views on the importance of ‘the voice of mankind, and the course of the world, that is, of human life and human affairs’, in ‘acquiring’ the knowledge of God, and of the need to ‘test, interpret, and correct’ what ‘the universal testimony of mankind … the history of society and the world’ present ‘to us for belief’.

Newman to Lewis via Chesterton

I have argued that in these three important respects Chesterton's methodology as an apologist so closely resembles that of Newman as to give strong indications of influence. What of C.S. Lewis and the next generation of Christian apologists? Might Newman's influence have reached through Chesterton to affect Lewis's methodology as an apologist? Lewis was himself very clear that Chesterton had been a great influence on him,Footnote ³² writing, for example, that ‘the case for Christianity in general is well given by Chesterton,’ and calling Chesterton's The Everlasting Man, ‘the best popular apologetic I know’.Footnote ³³ Iain Benson and numerous others have charted the evidence for this in considerable detail.Footnote ³⁴ Zachary Rhone has analysed the relationship between Chesterton and Lewis at the level of worldview, observing many affinities and shared patterns of thought: he notes that in their apologetics both contrast a Christian humanist, mystical worldview with an empirical, materialist scientism which provides knowledge without wisdom, attempts an illusory complete knowledge, and loses clear distinctions between good and evil, thus creating a shifting morality. Rhone's very thorough study has provided a vast weight of evidence for Chesterton's influence on Lewis, without, however, exploring Newman's role.Footnote ³⁵

Chesterton's influence can be discerned in all the three areas of methodology discussed in this essay. In relation to worldview, consider The Abolition of Man: in this book, rather than relying on Christian authorities, Lewis makes the Tao central to his defence of natural law and calls numerous authorities from other religions and philosophies to support his case for a Christian theological anthropology.Footnote ³⁶ His strategy in his book resembles that pursued by Chesterton in The Everlasting Man, and numerous other works. In The Everlasting Man Chesterton suggests that the best dreams of ‘all the sages’ were fulfilled in Christ and that ‘all heathen humanity’ are conscious of the Fall.Footnote ³⁷ In Orthodoxy, he brings in all humanity and all religions as witnesses for the Christian concept of sin: ‘All humanity does agree that we are in a net of sin … The ancient masters of religion … began with the fact of sin’.Footnote ³⁸ In the same book, he declares: ‘the whole human race has a tradition of the Fall … every race of mankind remembers it’, again calling on authorities far beyond the Christian tradition to support Christian ideas.

Lewis works in a similar fashion at the beginning of Mere Christianity and in The Abolition of Man. In Mere Christianity, he argues that the ‘moral teaching’ of ‘the ancient Egyptians, Babylonians, Hindus, Chinese, Greeks and Romans’ is ‘very like … our own’.Footnote ³⁹ Having begun The Abolition of Man by citing Confucius, and continued it by calling on numerous other non-Christian sages as supporters of his argument, he ends the book with an appendix of citations which provide ‘illustrations of the Natural Law’, citations which are mostly not from Christian sources.Footnote ⁴⁰ As they read this appendix, students of Newman may well be reminded of his reference to ‘the primary teachings of nature in the human race, wherever a religion is found and its workings can be ascertained’,Footnote ⁴¹ or of one of his letters of 1877, in which he writes that Christianity continues a revelation that goes back to the dawn of time, so that he can see ‘the fragments of the great doctrines of Christianity in classical mythology’, adding: ‘For myself I have no difficulty in referring it, as so many Christian writers do, to a primeval tradition which is universal’.Footnote ⁴² In The Abolition of Man, Lewis in effect relates a Christian concept of natural law to ‘a primeval tradition which is universal’.Footnote ⁴³ In Newman's terms, he is bringing ‘the common voice of mankind’ to bear on his argument, presenting that testimony as being in accord with a Christian ‘interpretation’ of ‘the course of things.’Footnote ⁴⁴

Lewis, in Alister McGrath's words, argued that a Christian worldview ‘was able to offer a more satisfactory explanation of common human experience than its rivals’;Footnote ⁴⁵ this was very much Chesterton's approach, and he built on Newman's ideas in forming this way of working. Here Lewis, like Chesterton, follows the path envisioned by Newman in his call for Christian apologists to give ‘an interpretation to the course of things’, and investigate ‘the voice of mankind, and the course of the world, that is, of human life and human affairs’, in ‘acquiring’ the knowledge of God, and of the need to ‘test, interpret, and correct’ what ‘the universal testimony of mankind … the history of society and the world’ present ‘to us for belief’.Footnote ⁴⁶ The term ‘worldview’ was not yet in common use in English when Newman wrote those words,Footnote ⁴⁷ but he is sketching out the parameters of a precursor of the worldview apologetics of which Chesterton and Lewis are the great twentieth-century exemplars.

To illustrate Chesterton's influence, let us reflect on what is perhaps Lewis's most famous line. In Orthodoxy, Chesterton writes: ‘The one created thing which we cannot look at is the one thing in the light of which we look at everything. Like the sun at noonday, mysticism explains everything else by the blaze of its own victorious invisibility’.Footnote ⁴⁸ Compare Lewis's famous remark: ‘I believe in Christianity as I believe that the Sun has risen, not only because I see it, but because by it I see everything else’.Footnote ⁴⁹ Change the word ‘mysticism’ for the word ‘Christianity’ and the two statements are conceptually very similar.Footnote ⁵⁰ These statements epitomize a central aspect of the methodology used by Chesterton and Lewis in their apologetics: they are attempting to illustrate the explanatory power of a Christian worldview, using the visual metaphor to indicate that Christianity enlightens our vision, like the sun, enabling explanation and understanding of ‘human experience’.Footnote ⁵¹

In terms of interdisciplinary approach, Lewis constantly brings history, literature, culture, and philosophy into play in theological argument. This can be seen across his work: to list but a few short pieces, we might cite ‘Is Theology Poetry?’, ‘Christianity and Culture’, ‘Christianity and Literature’, ‘Sometimes Fairy Stories May Say Best What's To Be Said’, and ‘On the Transmission of Christianity’.Footnote ⁵² Another resemblance is that he takes a very positive attitude towards the value of pagan writings, following in a tradition of which Newman and Chesterton were also a part. In Newman's Apologia, he affirms the view that ‘pagan literature, philosophy, and mythology, properly understood’ are ‘but a preparation for the gospel’.Footnote ⁵³ Lewis takes a similarly sympathetic view to the insights of pagan philosophy, literature, and mythology.Footnote ⁵⁴

To take a specific example, in the essay ‘Myth became fact’, Lewis follows very much the line of argument of Chesterton's The Everlasting Man, in compressed form. In that book, Chesterton argues that ‘Mythology is a search’ which is fulfilled by encounter with the Incarnation, which ‘fulfilled not merely the mysticism but the materialism of mythology’, and that philosophy is also a search, for ‘the truth of things’, which is also completed and fulfilled in the revelation of Christ; this fulfilment builds on the existing search, so that ‘for philosophy as much as mythology, that reward was the completion of the incomplete’; he suggests that because it is both myth and fact the Incarnation can satisfy, on the one hand, the poet and the mystic, whose thinking centres on the imagination, and, on the other hand, the philosopher, whose work is built on reason.Footnote ⁵⁵

In ‘Myth became fact’, Lewis writes in the same terms, asserting that ‘The heart of Christianity is a myth which is also a fact’, and this satisfies both ‘the poet’ and ‘the philosopher’. Like Chesterton, Lewis insists on the need for both myth and fact: ‘In the enjoyment of a great myth we come nearest to experiencing as a concrete what can otherwise be understood only as an abstraction … What flows into you from the myth is not truth but reality (truth is always about something, but reality is that about which truth is)’; he adds that humans ‘receive’ myth with ‘imaginative embrace’, whereas ‘Human intellect is incurably abstract’.Footnote ⁵⁶ His terminology here, and the distinctions he makes, parallel Newman (and Chesterton followed Newman closely in this).Footnote ⁵⁷ Newman argued that religious dogmas are ‘discerned, rested in, and appropriated as a reality, by the religious imagination’ and ‘held as a truth, by the theological intellect’; he also gave an important role to the concrete, as opposed to the abstract: ‘What is concrete exerts a force and makes an impression on the mind which nothing abstract can rival. … It is in human nature to be more affected by the concrete than by the abstract’.Footnote ⁵⁸ Lewis is using the same categories, with the same relationships between reason and imagination, and between the concrete and the abstract.

Lewis also follows Newman and Chesterton in the very positive use he makes of that branch of philosophy known as natural theology. Newman was once again the precursor, in his extremely sympathetic treatment of natural religion and, hence, of the natural theology implicit in the natural religion he endorsed. In the second of his University Sermons he writes: ‘There is, perhaps, no greater satisfaction to the Christian than that which arises from his perceiving that the Revealed system is rooted deep in the natural course of things, of which it is merely the result and completion; that his Saviour has interpreted for him the faint or broken accents of Nature; and that in them, so interpreted, he has, as if in some old prophecy, at once the evidence and the lasting memorial of the truths of the Gospel’. He goes so far as to claim that there is no ‘essential character of Scripture doctrine’ which is not to be found in what he called ‘the Dispensation of Paganism’; that Natural and Revealed Religion ‘coincide in declaring the same substantial doctrines’, with the exception of ‘one solitary doctrine, which from its nature has no parallel in this world’, the Incarnation; and that, ‘concerning Divine Providence’, ‘Nature and Scripture … teach the same great truths’.Footnote ⁵⁹ While Newman writes of natural religion here, he refers to ‘substantial doctrines’ and ‘great truths’ which take him on to clearly theological ground, showing that a particular natural theology is involved in his conception of natural religion.

In A Grammar of Assent, Newman claims that ‘we find in Scripture our Lord and His Apostles always treating Christianity as the completion and supplement of Natural Religion’, and, in words highly relevant for apologists and their apologetics strategies, declares that those who are likely to respond to arguments for Christianity are: ‘those only whose minds are properly prepared for it; and by being prepared, I mean to denote those who are imbued with the religious opinions and sentiments which I have identified with Natural Religion’.Footnote ⁶⁰ Chesterton and Lewis follow in Newman's footsteps here, as they both use natural religion and natural theology to ‘properly prepare’ their readers for Christian argumentation, in works such as The Everlasting Man, Orthodoxy, Mere Christianity, The Problem of Pain, and The Abolition of Man.

Lewis's use of natural theology relates closely to Newman's thinking, as developed by Chesterton. In Mere Christianity and The Problem of Pain he uses natural theology to make the case for Christianity in philosophical terms, without reliance on revelation; Chesterton, in a less rigorously philosophical way, used natural theology in Orthodoxy, until the very end of that book, and for the greater part of The Everlasting Man. To take a specific example, in Mere Christianity, Lewis begins his argument with the assertion that ‘the human race’ is ‘haunted by the idea of a sort of behaviour they ought to practise’;Footnote ⁶¹ in A Grammar of Assent, Newman takes conscience as his ‘first principle, which I assume and shall not attempt to prove’; both start with conscience.Footnote ⁶² Lewis proceeds to make natural law foundational to his argument in both Mere Christianity and The Abolition of Man, linking natural law closely to conscience, as Newman does.

Newman's stringent critique of Paley's natural theologyFootnote ⁶³ has obscured the fact that his treatment of natural religion denotes a positive attitude towards the natural theology implicit in the natural religion he discusses in such enthusiastic terms. Newman did not himself draw out the full theological implications of his view of natural religion, yet a religion must have a theology, and his warm support for natural religion indicates support for the forms of natural theology that are implied by and embodied in that natural religion. Chesterton goes on to develop Newman's ideas in this regard, making explicit the natural theology implicit in Newman's view of natural religion; Lewis, in a more academic manner, employs a similar strategy as regards natural theology in The Abolition of Man, The Problem of Pain, and Mere Christianity.

In relation to the Illative sense, Lewis, like Chesterton and Newman, took the view that Christianity can be shown to be probable but that conclusive and final proofs are not possible in many debates. Chesterton uses ‘converging reasons’ and the ‘accumulation of varied facts’ to build towards his conclusions in a way that parallels Newman's use of ‘converging probabilities’ and ‘cumulation of probabilities’;Footnote ⁶⁴ Lewis takes a very similar approach. For example, he writes in a letter to Sheldon Vanauken: ‘I do not think there is a demonstrative proof (like Euclid) of Christianity, nor of the existence of matter, nor of the good will & honesty of my best & oldest friends. I think all three are (except perhaps the second) far more probable than any alternatives’. Lewis continues: ‘As to why God doesn't make it demonstratively clear: are we sure that He is even interested in the kind of Theism which would be a compelled logical assent to a conclusive argument?’Footnote ⁶⁵ Lewis's ‘probable’ echoes Newman's and Chesterton's emphasis on the role of probability and the absence of final and ‘conclusive argument’ in such matters; like Newman, Lewis is making probability ‘the very guide of life’ (Newman, of course, was following Joseph Butler in this).Footnote ⁶⁶