Irenaeus is a supremely useful figure for understanding the relationship between knowledge and pedagogy in catechesis. A bishop in Lyons in the late second century, Irenaeus is a key witness of early Christian uses of the Rule of Truth, which he says is “received in baptism,” and he is also the author of one of the first potentially catechetical texts in early Christianity, the Demonstratio apostolicae praedicationis. Despite this attraction, however, a clear picture of catechetical practice in Irenaeus’s setting remains elusive. It is by no means clear that the discussions of the Rule of Truth in his extant writings actually correspond with pre-baptismal education. And it is much contested whether the Demonstratio was in fact catechetical.Footnote ¹

Despite these limitations, there is, I hope to show, still much to learn about knowledge and pedagogy in Irenaeus’s writings. Though his extant writings may not contain explicit samples of pre-baptismal catechesis, the references to the Rule of Truth in the Aduersus haereses and the Demonstratio can offer important clues as to how catechetical instruction might have been undertaken.Footnote ² Careful attention to these moments may help us deduce the pedagogical and epistemological components at work in Irenaeus’s catechesis.Footnote ³ In particular, I argue that the appeals to the Rule of Truth in the Aduersus haereses and the Demonstratio reveal an aesthetic approach to the knowledge of God in Irenaeus’s catechesis – one in which the Rule of Truth provides a principle of unity that enables the learner to understand the coherence of Scripture and the divine economy, thus bringing the one guided by the Rule to the worship and praise of the one God.Footnote ⁴ The regula ueritatis, in Irenaeus’s writing, may not be a proto-credal outline of content, but we might see, in its concise form, a pedagogical device that presents the unity of vision necessary to hold together the diverse aspects of God’s creative and redemptive work. In presenting knowledge of God through the Rule in aesthetic terms – relying on metaphors drawn from the visual, literary, and musical arts – Irenaeus links pedagogy not only with baptism but also with doxology. The Rule was intended to generate in Christians a kind of knowledge that led to loving and praising the divine artist.

Irenaeus’s aesthetic approach to knowing God came at a crucial juncture in the history of early Christianity. It was precisely during this time when catechesis was becoming formalized as a teaching institution within the emerging monepiscopate. In what follows, I situate Irenaeus’s arguments about knowledge and pedagogy within this transitional period, taking note of Irenaeus’s appreciation and appropriation of classical learning as part of his approach to teaching. I then turn to his appeals to the Rule of Truth, first in the Aduersus and then in the Demonstratio, to glean what evidence they might yield for understanding Irenaeus’s approach to knowledge. Through focusing attention on the aesthetic perception of the Word and Spirit in creation, Irenaeus aimed to bring Christians to an understanding of the “true nature of reality.”Footnote ⁵

The Bishop as Teacher and Classical Education in Anti-Gnostic Polemic

A Greek-speaker from Asia Minor, Irenaeus came to Lyons at some point in the 170s along the trade route that traversed the Roman Empire.Footnote ⁶ Though operative primarily in Lyons in the late second century, he was closely connected with the Roman episcopacy. This was a transitional period in ecclesiastical organization, between the school model age of Valentinus, Marcion, and Justin, on the one hand, and the centralized monepiscopate that emerged by the mid third century, on the other.Footnote ⁷ While Irenaeus operated at certain moments like a monarchial bishop – utilizing strategies to remove oppositional church leaders from communion – he did so by projecting the role of bishop in the older style of a teacher and educator. Moreover, he did so by portraying the orthodox bishop as a teacher invested in knowledge and learning, while presenting heretical Christians as those whose cosmological dualism prevented them from appreciating the fruits of classical paideia. Here, Irenaeus helps us understand how emerging teaching institutions were related to particular approaches to knowledge.

By the end of the second century, Christians had developed a variety of what David Brakke has called “strategies of self-differentiation.”Footnote ⁸ Valentinians, no less than the proto-orthodox, could narrate an apostolic succession by which the secret teaching of Christ was transmitted, providing access to the spiritual gnosis of Scripture in contradistinction from the knowledge entrusted to psychic Christians.Footnote ⁹ In Alexandria, Clement promoted his teaching as a form of true gnosis beyond those who had only “bare faith”; he also claimed access to a “mother church” and an “ecclesiastical rule” that distinguished true and false practices.Footnote ¹⁰ According to Brakke, Irenaeus’s writing demonstrates a strategy of self-differentiation in which the role of bishop was understood as more practical and juridical – “enforcing with practical measures the truth that he received from the apostles.”Footnote ¹¹ Such practical measures included the reservation of the term “teachers” for leaders of (heretical) “schools” while “bishops” were those who oversaw a “church,” and the articulation of corresponding genealogies for each.Footnote ¹² In Demonstratio 2, Irenaeus refers to those who sit in the “chair of pestilence” (Ps. 1:1) as heretical teachers “who pervert themselves and others through twisted teaching, since ‘chair’ is a symbol of a school (διδασκαλεῖον).”Footnote ¹³ In addition, he used the Rule of Truth as a polemical tool to demarcate his opponents’ false teaching.Footnote ¹⁴ Finally, Brakke mentions the way Irenaeus developed literary networks with other bishops to remove his opponents from communion.Footnote ¹⁵ Through such techniques, Irenaeus’s understanding of episcopacy appears, to Brakke, more like those of later monepiscopal Christianity than earlier school Christianity.

At the same time, however, Irenaeus continued to view the bishop’s role in more traditional terms, especially in his emphasis on the bishop’s duty as a teacher. While the bishop’s role entailed demarcating the boundaries of orthodoxy, his authority to do so was conceived not in juridical terms but as an expression of the faithful transmission of authentic apostolic teaching. For Irenaeus, as Paul Parvis argues, the bishop’s role is authoritative not because he iterates the authoritative function of the apostles but because he faithfully teaches their doctrine.Footnote ¹⁶ In addition, Irenaeus’s practice of tracing genealogies of orthodox bishops does not function the same for Irenaeus as it did for later writers. His genealogies, while faithfully preserved in Eusebius’s writing, takes on a different meaning in the later context. For Irenaeus, the genealogical narration parallels similar practices among ancient philosophical schools, such as the examples we find in Diogenes, in which genealogies help establish the legitimate, faithful transmission of the sage’s teaching.Footnote ¹⁷ For Eusebius, however, the genealogies function to promote a more juridical picture of episcopacy. Thus, while Irenaeus does reveal new forms of church leadership, he continued to view the bishop as performing a pedagogical role, one that we can locate still within the second-century school model of Christianity.

Irenaeus’s pedagogical conception of the bishop also helps us understand his appreciation of classical learning and engagements with philosophical modes of reasoning. While Irenaeus was once viewed as largely skeptical of philosophical reasoning,Footnote ¹⁸ more recent work has perceived Irenaeus’s debts to classical traditions more positively.Footnote ¹⁹ Classical learning was not an unmitigated good for Irenaeus, to be sure, but it could be brought into the service of Christian goals. For instance, Irenaeus could claim that his opponents rejected classical learning as a corollary of their cosmic dualism.Footnote ²⁰ At the same time, classical education could function positively for Irenaeus, with pedagogical imagery serving as aids to depict God’s involvement in creation and redemption.Footnote ²¹ In terms of epistemological issues, a key passage from Aduersus haereses 2.6.1 shows how Irenaeus drew on philosophical reasoning for understanding natural knowledge of God.Footnote ²² Whereas a strong “gnostic” view of divine transcendence entailed angelic and demiurgical ignorance, Irenaeus contended that divine transcendence correlated with a notion of divine providence that permitted a certain natural knowledge of God. He writes that God’s “invisible essence, since it is powerful, procures in all a profound mental intuition and perception of his most powerful, even omnipotent eminence,” which occurs because “reason, implanted in their minds, moves and reveals it to them that there is one God, the Lord of all.”Footnote ²³ While interpreting Irenaeus’s meaning here is complex, it is clear that, when it served his purposes, Irenaeus could reason against his opponents using the tools of philosophical reasoning; for him, issues of learning and pedagogy were important for articulating a vision of theological knowledge.

In summary, though Irenaeus could utilize practical strategies for differentiating true and false believers in ways that presaged monepiscopal Christianity, he nonetheless continued to understand the bishop’s role in the more traditional terms of a pedagogical teacher, in line with the second-century model. Irenaeus, that is, helps us see the ways in which older contestations about the role of education became transposed into the early Christian catechumenate.

Catechesis as a Novel Teaching Institution

Irenaeus’s writing reveals some of the earliest evidence of a formalized catechumenate.Footnote ²⁴ More specifically, we can locate his use of catechetical language in the context of describing the Christian mission to non-Jewish audiences. For those who did not know the Jewish Scriptures and their basic theological and biblical convictions, a new form of instruction was necessary. In this setting, we see the importance of theological commitments about the nature of God and creation as constitutive of theological epistemology. A catechetical program focused on learning to perceive God’s relation to the created order – what I will describe as the aesthetics of knowledge – was especially relevant for demonstrating to Gentiles what it means for Jesus Christ to reveal true knowledge of God.

Catechetical language first appears in Book 3 of Aduersus haereses , where Irenaeus describes Peter’s “catechizing” (catechizandos) of the Jews in relation to their understanding of the one God and their reception of the Holy Spirit.Footnote ²⁵ Later, in Aduersus haereses 4.23.2, when describing Philip’s baptism of the Ethiopian Eunuch, Irenaeus says that the Ethiopian had been “precatechized” (praecatechizatus) by the prophets, which made for a more straightforward instruction.Footnote ²⁶ Because the Eunuch had been studying the Scriptures, he was already familiar with the concept of God the Father and the Jewish “way of life” (conuersationis dispositionem); he was only ignorant of the coming of Christ. Once instructed, the Eunuch returned to Ethiopia rejoicing. “Therefore,” Irenaeus concludes, “Philip had no great labor to go through with regard to this man, because he was already prepared in the fear of God by the prophets.”Footnote ²⁷ Here, Irenaeus uses the language of “precatechesis” to describe the preparatory instruction of the Scriptures, which is primarily the Old Testament. From this oblique passage, we can gather that such instruction included, at least, a basic monotheistic cosmology and core aspects of Jewish ethical teaching.

If the instruction of the Jews was rather straightforward, the conversion of the Gentiles was much more laborious. In the following section, Irenaeus connects the mission to the Gentiles with Paul’s claim to have “labored more than the rest” (1 Cor. 15:10). The “catechesis” (catechizatio) of the Jews was easier, Irenaeus explains, because the apostles could draw upon the Law and the Prophets in their demonstration of Christ as “first-begotten of the dead and the prince of life.”Footnote ²⁸ Without having the kind of scriptural tutelage of the Ethiopian Eunuch, the Gentiles needed to be “first catechized” (primo catechizabat) on a number of topics that would have been better known to someone familiar with the Jewish Scriptures.Footnote ²⁹ Paul taught them, for example,

This description of Paul’s “first catechesis” bears a striking resemblance to what Irenaeus will elsewhere describe as the Rule of Truth – namely, a focus on creational monotheism and the unity of the Word’s role in creation and redemption. While the Jews, according to Irenaeus, already knew the Scriptures and these basic tenets, the Gentiles needed foundational instruction on the meaning of creation and redemption as the work of one God through the divine Word.Footnote ³¹ In this setting, catechetical language is identified with two kinds of introductory teaching: for the Jews, in proclaiming Christ’s advent; for the Gentiles, the core tenets of monotheism and the unity of creation and redemption in the Word.

It is highly instructive that Irenaeus uses catechetical verbiage in precisely these contexts. I suggest that it is here we find the best indication of how the Rule of Truth might have functioned as a form of baptismal education. Irenaeus’s vocabulary evinces a need to engage different audiences with specifically targeted teaching. In particular, the language of catechesis emerged to describe the mission to the Gentiles, in which certain foundational teaching was needed to provide a subset of beliefs and practices in which the advent of Christ as divine Word or Son of God could be intelligible. The gospel proclamation needed first to be textured by an initial catechesis on the first principles of God, creation, and the Christian way of life.

The Catechetical Function of the Rule of Truth in Aduersus haereses

This picture of the institutional context of catechesis allows us to appreciate the approach to shaping knowledge we can glean from Irenaeus’s various appeals to the Rule of Truth, which occur in both the Adversus haereses and in the Demonstratio. Once again, I do not assume that what we find in these texts corresponds precisely with what Irenaeus may have taught in catechesis during this period. Notwithstanding the Demonstratio’s potential provenance as a catechetical text and Irenaeus’s claims that the Rule of Truth is “received in baptism,” it is not clear that these statements provide an example of pre-baptismal instruction as such.Footnote ³² What I am attempting in what follows is to elucidate, on the basis of his discussions of the Rule in these texts, what might have been the epistemological function of the Rule in catechesis. These can only be estimations, to be sure, but they are, I think, reasonably plausible. We find, in these moments, Irenaeus appealing to the Rule to shape an aesthetic mode of attention to creation as ordered by and commensurate with divine action – a fitting expression of God’s creative agency through his Word and Spirit. As a pedagogical tool, the Rule served both to express and shape an aesthetic mode of attention to creation as revelatory of God’s creative and redeeming work in the world.

Among the vast amount of scholarship on the Rule of Truth, most studies have focused on the Rule’s polemical or anti-heretical function, its role vis-à-vis scriptural interpretation, and its relation to later baptismal creeds.Footnote ³³ A few studies, however, have ventured to explore the Rule’s more constructive functions. William Countryman, for example, argued that the Rule’s flexible semantic range suggested an “oral composition” most likely employed in catechetical instruction.Footnote ³⁴ Paul Blowers has explored the ways in which the Rule might have contained a narrative-based mode of identity-formation in pre-Nicene Christianity.Footnote ³⁵ Most recently, Lewis Ayres has sought to demonstrate the Rule’s metaphysical entailments – originating in anti-gnostic polemic but divulging an epistemological paradigm that pairs a certain creational metaphysics with a theological epistemology.Footnote ³⁶ This line of scholarship helpfully situates the following discussion on the aesthetic approach to knowledge underlying Irenaeus’s appeals to the Rule of Truth.

Irenaeus uses the language of “Rule of Truth” at several points in both the Aduersus haereses and the Demonstratio. These are relatively well known and so we need not rehearse them at length here. Instead, I will highlight just a few key passages that illuminate what I am calling Irenaeus’s aesthetic approach to theological knowledge. One such instance is the discussion of the Rule in Aduersus haereses 1.9–10. Here, Irenaeus concludes a lengthy exposition of Valentinian exegesis in which he describes them as “collect[ing] a set of expressions and names scattered here and there and twist[ing] them … from a natural to a non-natural sense.”Footnote ³⁷ Irenaeus, notably, compares this approach to two kinds of artistic practices – the way a schoolteacher might create centos out of the Homerian corpus and the way an artist may rearrange a tile mosaic. The student who has actually read Homer, however, knows the story’s true hypothesis and so can recognize how certain passages have been wrenched from their natural place.Footnote ³⁸ Likewise, the Christian who “retains unchangeable in himself the rule of truth received through baptism” will be able to place various scriptural teachings and episodes within a comprehensive theological framework.Footnote ³⁹ The Rule will enable the student to “restore every one of the expressions quoted to its proper position and to fit it to the body of truth.”Footnote ⁴⁰ The student will, in Irenaeus’s famous image, be able to place the mosaic tiles of Scripture in their proper order so as to envisage a king instead of a fox.Footnote ⁴¹

We note, first of all, that what we find here is not a description of catechetical instruction but a way in which the Rule “received in baptism” can now be applied for detecting the misreading of Scripture among heretics. The comparison with reading Homer using school techniques provides an interesting clue about the kind of pedagogical function that the Rule might have served in baptismal teaching.Footnote ⁴² In particular, it suggests something about how the Rule was related to memory and vision. The Rule is not only received in baptism but also must be “held in oneself” (habet in se). It must be internalized in such a way that, as Epicurean students learned, one could grasp the whole system in one glance, to envision the entire “body of truth” and know how various particulars fit within the comprehensive whole. The use of the mosaic image suggests, moreover, the aesthetics of the Rule’s mnemonic pedagogy. Like other antique educators, Irenaeus appreciated the visual organization of memory for coming to a proper evaluation of truth. Not unlike the way Platonic epistemology required envisioning the forms in order to gain knowledge of particulars, Irenaeus presents the Rule as providing the key to a unitive vision of God’s ordering of creation that allows the believer to perceive the coherence of creation as the product of the one God who both creates and redeems. Conceiving truth as a “body” – with the various parts in their respective places – enables the student to grasp how created being is arranged aesthetically, and, as well, to recognize when the body of truth had been disarranged. The Rule is meant to inculcate a mode of perception in which attention to the entire scope of faith enabled one to arrange its constituent parts. Having received the Rule of Truth in baptism, Irenaeus asks his readers to recall it at certain moments, to recollect its systematic presentation of the faith, to detect when heretical portraits have distorted the true image.

Another example of the aesthetic character of the Rule appears in the discussion of theological method in Aduersus haereses 2.25–28.Footnote ⁴³ Here, Irenaeus draws together a series of arguments about perceiving creation’s harmonious order as a testimony to the one divine artist, which in turn shapes a form of theological knowing. Through a process of daily meditating on Scripture and creation with the Rule constantly “at hand,” the Christian can make progress in divine knowledge. Beginning at Aduersus haereses 2.25.2, Irenaeus articulates the harmony of a diverse creation with a musical analogy.Footnote ⁴⁴ When viewed individually, created beings may appear in discord, but with the right guide, they appear like the diverse notes of a musical score. Perceived as such, one discerns the master musician authoring a harmonious symphony rather than a cacophony of multiple competing musicians.Footnote ⁴⁵ Irenaeus suggests here how the Rule serves to maintain a contemplative view of creation that eventuates in praise: he “who listens to the melody ought to praise and extol the artist … never failing to apply our rule (regula), neither giving up the [one] artist, nor casting off faith in the one God who formed all things, nor blaspheming our Creator.”Footnote ⁴⁶ The Rule in this passage functions as shorthand not simply for certain doctrinal tenets but also for a way of perceiving the world in relation to God. By “holding firm” to the regula, Christians have a reliable source of knowledge that will foster not only a sound reading of Scripture but also a manner of seeing the world as the manifestation of God’s creative work – a mode of vision that manifests in praise.

These arguments give way to an explicit discussion of the Rule as facilitating a right reading of Scripture in Aduersus haereses 2.27–28. Here, Irenaeus tells us that the lover of truth will “eagerly meditate” upon and “make advancement” in the knowledge that God has placed within human capacity to know, “rendering knowledge … easy to him by means of daily study.”Footnote ⁴⁷ Through daily meditation and study of the Rule, the lover of truth can read the Scriptures and interpret creation in a way that leads to systemic comprehension: the “body of truth remains entire” (ueritatis corpus integrum), with various members and individual parts brought into a harmonious adaptation and relieved of conflict.Footnote ⁴⁸ If one proceeds otherwise, however – if one “applies expressions that are not clear or evident to the interpretation of parables” – that person will no longer “possess the Rule of Truth” (regula ueritatis) but will be led to as many antagonistic opinions as are common among the Gentile philosophers.Footnote ⁴⁹ Such a person will be “always inquiring but never finding, because he has rejected the discipline of discovery” (inuentionis abiecerit disciplinam).Footnote ⁵⁰ Here, at the same time he uses the trope of philosophical disagreement to characterize his opponents, he demonstrates the philosophical provenance of the regula and its close correlation with memory and the discovery of theological knowledge.

This appeal to the Rule is clearly not an admonishment to avoid intellectual speculation. It is, rather, an appeal to apply the Rule in a philosophical way. The exhortation to “hold” to the Rule suggests that it be assiduously studied and meditated upon. Attentive meditation aids the “exercise” of investigation into divine mysteries, training one to envision the world as the melodic arrangement of the master artist.Footnote ⁵² Such a practice is crucial not only for growing in knowledge, of course; the frequent exercise of scriptural reasoning with the Rule enables the Christian to know God in a way that manifests in love (caritas) for the one true God.

The preceding passages have found Irenaeus invoking the Rule mostly implicitly. They give only an oblique indication of what kind of content the Rule included. Two other appeals to the Rule, however – in Aduersus haereses 1.22.1 and 3.11.1 – provide further evidence of the Rule’s potential function in catechesis by outlining a sketch of the Rule’s basic content. In the first passage, Irenaeus’s reflection on the Rule is devoted to articulating creation as the product of the one true God, warding off interpretations of creation in which creation and redemption are seen as the product of competing powers. He writes: “The Rule of Truth that we hold is this: there is one God almighty, who created all things through his Word.” He goes on to clarify biblically and polemically what this means. He cites Psalm 32:6 and John 1:3 in this passage as evidence of God’s creative agency through the Word and Spirit, and contrasts this understanding with viewing creation as the product of a Demiurge, angelic mediators, or series of eons. “For God needs none of all these things, but is he who, by his Word and Spirit, makes, and disposes, and governs all things, and commands all things into existence.”Footnote ⁵³ Irenaeus’s deployment of the Rule here is, to be sure, polemical, but even still, it highlights certain aspects of the content of the Rule and how it might have functioned pedagogically. By emphasizing the Word and Spirit as integral to divine creative activity, Irenaeus emphasizes both their identification within the Godhead and also their immanent role in the created world. The Word is both beyond the spiritual powers and principalities yet also more immediate to creation, having removed the multiple levels of intervening aeons. In this articulation, we see how the Rule helped Irenaeus teach Christians to envision the unitive relation between God and creation, providing the key to understanding how diverse aspects of created time and matter find their origin in the one God. We can suggest here – again, cautiously – that a pedagogical function of the Rule was to facilitate a vision of creation as a sphere receptive to divine interaction via God’s Word and Spirit.

A similar set of concerns occupies Aduersus haereses 3.11.1. In this passage, the focus is primarily on the Johannine Prologue, which for Irenaeus teaches that the one God created all things through the Word:

Creation is the workmanship of the one God, who creates all things through his Word and likewise bestows salvation. The mention of redemption here might seem to indicate a second article of a trinitarian formula, but, as Ayres notes, it “does not so much introduce a second ‘article’ as emphasize that the same God who created through his Word, also saved through his Word.”Footnote ⁵⁵ Indeed, in this context, Irenaeus is concerned to argue that the creation is entailed in the “all things” made and redeemed by the Word, and not only to those things within the Pleroma.Footnote ⁵⁶ Against seeing the Rule as simply presenting either a trinitarian credal formula or a narrative of creation, fall, and redemption, we should also notice how this appeal to the Rule is governed by an attempt to envision creation aesthetically, focusing on the unitary work of Christ in both creation and redemption. In this way, both Aduersus haereses 1.22 and 3.11 highlight that a true perception of creation and the creative agency of the divine Word is central to the pedagogical function of the Rule of Truth.

Irenaeus’s appeals to the Rule attest to the oft-noted flexibility and multivalent applications of it in pre-Nicene Christianity. Moreover, we can affirm that the Rule was an important tool in the polemical construction of orthodoxy. At the same time, however, Irenaeus’s discussions of the Rule also suggest important clues about the pedagogical nature of early Christian teaching, and quite likely in baptismal teaching. While these passages do not explicitly indicate the content or method of baptismal catechesis, we find recurring themes in Irenaeus’s writing about the Rule that potentially shed light on baptismal instruction. In particular, his discussions repeatedly center upon the aesthetic perception of creation when seen in light of the Rule’s emphasis on the creating and redeeming role of the Word and Spirit in the divine economy. The Rule – given in baptism and then meditated upon and “held fast to” by believers – trains Christians to perceive the multiplicity of the world as the craftsmanship of the one God who operates through Word and Spirit.Footnote ⁵⁷ These passages indicate not just a list of topics for orthodox Christians to believe but also – more interestingly – a certain mode of attending to the world. Irenaeus, we can hypothesize, used the Rule in baptismal contexts to focus attention on the harmonious nature of creation, which revealed and enabled the praise of creation’s divine artist.

Catechesis in the Demonstratio

Since the discovery in 1904 of an Armenian translation of the long lost Demonstratio apostolicae praedicationis ascribed to Irenaeus by Eusebius, scholars have been divided about whether this work constitutes a strictly catechetical work.Footnote ⁵⁸ Many readers have questioned its catechetical orientation based on the fact that there is no explicit indication of its use in baptismal settings, and that its organization and structure might have other purposes than strictly catechetical ones.Footnote ⁵⁹ Of note here is an important article by Susan Graham, who argues that Irenaeus drew on ancient isagogical (είσαγωγαί) literature to organize the Demonstratio into a two-part historia-theoria structure; while introductory, this work better fits “continuing education” rather than pre-baptismal catechesis.Footnote ⁶⁰ For those who do view the work as catechetical, most appeal to its summative and non-polemical character, proposing that its recipient, Marcianus, was a catechist whose task was both to refute opposing views and to articulate apostolic teaching clearly for those desiring to know.Footnote ⁶¹ Everett Ferguson has presented perhaps the most fulsome argument in favor of its catechetical orientation based on its underlying “history of salvation” structure, which for Ferguson is the primary marker of pre-Nicene catechesis.Footnote ⁶² The more recent view by Stephen Presley grants its generally catechetical character, but argues that it is focused on providing a “catechetical hermeneutic” of Scripture rather than basic instruction in doctrine, morals, or salvation history.Footnote ⁶³

While I do not know if one can definitively argue that this work was strictly catechetical, its designation as introductory or isagogical literature, which seems relatively uncontested, should prevent us from excluding that possibility. Considering this work alongside, for example, Tertullian’s De spectaculis and De baptismo, where both pre-baptismal candidates and novice believers are the main audience, it seems best to consider the Demonstratio as a text that served multiple purposes, including catechetical instruction.

Regardless, even if one does not grant a catechetical provenance, we can still learn much from this work about the kind instruction that catechumens might have received in baptismal teaching, especially given the orienting role that Irenaeus gives to the Rule of Faith in the opening chapters. Building on the analysis from the preceding section, we can suggest that the discussion of the Rule in the Demonstratio exhibits the trinitarian foundation and exegetical application of Irenaeus’s aesthetic epistemology. Irenaeus attempts to show how the diversities and variations in Scripture and creation find their unity in Christ as revealed by the Holy Spirit.Footnote ⁶⁴ The Rule serves, in this work, to orient the reading of Scripture within an ontology in which the demonstration of Christ’s fulfillment of Old Testament prophecies are grounded in a vision of creation and history ordered by, as John Behr’s translation puts it, “a true comprehension of what is” (dem. 3).Footnote ⁶⁵ We might see, in other words, an example here of Irenaeus arranging the tiles of Scripture in the image of a king, not a fox or a dog; it is a true image not only because it is biblically accurate but because this picture aligns with the nature of reality. By learning to see the Spirit-inspired prophets as finding their harmonious summation in Christ, the Rule guided Christians in seeing Scripture and the created order as united in the creative and redemptive work of God’s Word and Spirit.

One of Irenaeus’s main tasks in the Demonstratio is to present the apostolic teaching and scriptural prophecies in a way that gathers the seemingly discordant notes of history and to demonstrate their order and consonance in Christ. In bringing harmony to the multitudinous events of biblical history, Irenaeus models not only a way of reading Scripture but also a way of ordering knowledge.Footnote ⁶⁶ Indeed, the hermeneutical program that makes up the bulk of the Demonstratio is grounded in a dense account of creation’s trinitarian ordering. In the opening chapters, Irenaeus treats the Rule of Faith with a focus on its connection with knowing reality “as it really is” – as the handiwork of a trinitarian God. For Irenaeus, the Rule of Faith grounds proper action in the world because it initiates one into the knowledge that is commensurate with reality itself. Irenaeus writes:

This statement about the Rule introduces the benefits of faith procured in baptism: remission of sins in the name of the Father, Son, and Holy Spirit; the seal of eternal life and rebirth unto God; being transferred from the family of mortals to the divine; and a restoration of the proper order of things in which God rules over all that God has created. The focus on faith and reality would counter Valentinian or Marcionite approaches to divine knowledge, which, according to Irenaeus, extricate gnosis from creaturely life. Irenaeus insists instead that the measure of faith presented in the Rule eventuates in the comprehension of things as they really are. Employing Isaiah 7:9, a text that will be important to Augustine’s theological method, Irenaeus presents the Rule of Faith as the premise for understanding the true nature of reality. It is not simply that faith leads to knowledge, however. Faith develops into knowledge, according to Irenaeus, because the Rule of Faith is itself founded upon truth – upon that which really is. Faith procures knowledge of truth because it is, in a very real way, founded upon the truth at the heart of reality.

Having emphasized the Rule’s foundation upon true reality, Irenaeus elaborates the theological convictions of divine knowledge. Beginning with a presentation of creation’s dependence upon God, followed by an outline of creation’s trinitarian ordering, Irenaeus explains the cosmological framework that generates true knowledge. Irenaeus stresses that “things that have come into being have received the origin of their being from some great cause; and the origin of all is God, for he himself was not made by anyone, but everything was made by him.”Footnote ⁶⁸ Irenaeus takes as his starting point the ultimate supremacy and independency of the uncontained God and the related conviction that all creation depends upon God’s Word and Spirit for its existence.Footnote ⁶⁹ This is followed in Demonstratio 5 with Irenaeus’s mature view of divine creative agency:

Here, Irenaeus identifies the God who creates with the Father – the uncreated and invisible, above whom and after whom there are no other divine beings. Irenaeus then elaborates his view of divine being and creativity in a way that renders the Word and the Spirit internal to the divine being. The explication of Psalm 32:6 is presented now not as a claim about the Word only (as in haer. 1.22.1 and 3.8.3) but both Word and Spirit. This emphasis takes shape within a trajectory that locates the Word and Spirit within God’s creating activity, now with distinctive roles: The Word establishes the material substance of creation while the Spirit adorns and arranges its “powers” (δύναμεις). The Son as God’s Word and the Spirit as God’s wisdom are, in Irenaeus’s famous formulation, the “two hands” by which the invisible Father creates.Footnote ⁷¹ Against aeonic or demiurgical cosmologies that accent the distance between creation and God, Irenaeus stresses the proximity of the divine life to creation through the creative activities of the Son and Spirit.

This trinitarian view of creation is followed in Demonstratio 6–7 with a discussion of three articles, or “heads,” of faith (κεφάλαιον), and their baptismal orientation. The three articles provide both the “order of our faith” and “the foundation of the edifice and support of [our] conduct.”Footnote ⁷² The first article pertains to the Father, who is invisible, uncontained, and uncreated. The second article concerns Christ, the Son and Word of God, revealed through the prophets as creator and recapitulation of all things, who instantiates communion between God and humanity. The third article is about the Holy Spirit, who inspired the prophets, taught the patriarchs, led humanity in righteousness, and was poured out upon all flesh at Pentecost.Footnote ⁷³ Irenaeus does not identity these three articles specifically with the Rule of Faith. While it may be tempting to link the three heads with a triadic rule used in baptism, that is not exactly what is stated. Rather, what is at issue is a concern to locate the rationale for how the invisible Father is made visible to creaturely beings:

Irenaeus here outlines the economic framework that makes such vision possible, with attention to the particular roles of the Son and Spirit. Irenaeus, in other words, shares his opponents’ view that the Supreme God is transcendent and invisible. However, as we noted in Aduersus haereses 2.6.1, Irenaeus does not take divine transcendence to abrogate natural knowledge of God. Rather, the fact that there is one God who creates and rules over creation can be known through perception and intuition by the implanting of reason in human beings. What Irenaeus makes clear in this passage from Demonstratio, however, is that knowledge of God, understood as a participatory union with God, does not occur apart from the Son made known by the Spirit. The invisible Father is revealed through the visible imago, the Son, who in turn is revealed through the Holy Spirit’s active power in the lives of human creatures.

As the rest of the Demonstratio will go on to show, it is precisely the Spirit’s inspiration of the Prophets that enables the vision of and union with Christ. To know Christ as the one prophesied in the Law and the Prophets is a process of learning to see the Son as the image of the invisible Father.Footnote ⁷⁵ The trinitarian structure of baptism realizes a visual–epistemological conception of salvation in which mortal, visible flesh is provided the ocular means of communion with an immortal, invisible God. Attending to the grammar of baptismal regeneration – “unto God the Father through his Son by the Holy Spirit” – Irenaeus unfolds the order in which the Spirit reveals the Son who, as image of the invisible, provides a vision of the Father to the extent this is possible.Footnote ⁷⁶

The Demonstratio is richly suggestive in its presentation of an aesthetic theological epistemology. It is difficult, of course, to say whether this teaching would have appeared explicitly in baptismal catechesis. We simply do not have the evidence to know for sure. However, Irenaeus’s writing illuminates certain characteristics of the emerging character of catechesis as a knowledge-shaping practice. By connecting the baptismal Rule in Demonstratio 3, the trinitarian work of creation in Demonstratio 4–5, and the three baptismal articles in Demonstratio 6–7 as the foundation of understanding Christ’s fulfillment of scriptural prophecies, we see a likely focal point for Irenaeus’s understanding of the Rule of Truth in shaping knowledge through baptismal instruction.

Conclusion

The institution of catechesis was still nascent in Irenaeus’s time. He gives us some indication of its emerging structures and practices, but we are far from a clear-eyed view of how it actually functioned. Intriguing, though, are his frequent appeals to the Rule of Truth, which he says Christians receive in baptism, and the distinctively introductory character of the Demonstratio. I have tried to suggest a plausible way in which to read these texts as indicative of Irenaeus’s aesthetic approach to catechetical epistemology. In the Aduersus haereses, Irenaeus invokes the Rule to speak of creation’s diverse but harmonious order as the workmanship of a God who created through the two hands of Word and Spirit. In the Demonstratio, Irenaeus presents a dense account of creation’s trinitarian structure as a means of guiding Christians into true saving knowledge – providing a literary mosaic, as it were, of Scripture interpreted via the Rule of Truth. In these works, Irenaeus utilizes the Rule not only as a description of doctrinal tenets but also as a pedagogical tool for shaping a perception of creation as the handiwork of the one true God.

Irenaeus’s use of the Rule certainly anticipates later features of the monepiscopate – policing boundaries of orthodoxy, distinguishing true from false teachers. At the same time, however, Irenaeus remains within the orbit of second-century school Christianity, viewing the bishop as a teacher engaged with philosophical debates about knowledge and pedagogy. As Christianity developed from a federation of school-like communities into a monepiscopal system – a process that extended beyond Irenaeus’s time – catechesis began to emerge as a distinctive ecclesial practice for shaping knowledge of God. In this context, catechesis, we can hypothesize, entailed learning to envision creation’s receptivity to divine grace – a way of knowing God within the conditions of material and temporal history. The Rule of Truth provided an epistemological framework to guide a comprehension of God’s unitive work in creation and redemption – perceiving the diversities of creation as the workmanship of a single artist. Learning to perceive God in the world, in turn, was intended to provoke not only knowledge but also love and praise. An ascesis in the Rule garnered “a true comprehension of what is”Footnote ⁷⁷ and was intended to be a means of increasing in love for God: “Directing our inquiries after this fashion, [we] should exercise ourselves in the investigation of the mystery and administration of the living God, and should increase in the love of him.”Footnote ⁷⁸