Reflecting theology by a generic model of research designs ? Impulses from religious didactics

A pluralisation of religious and ideological convictions is currently taking place in many European countries (Pickel 2017). At the same time, the social significance of Christian churches is diminishing as a result of relatively high numbers of people who have left the churches and because of trends towards secularisation (Taylor 2007). These processes of pluralisation and secularisation also affect the academic status of theology. Its existence at universities, which has been taken for granted for centuries, is not only challenged by religious studies independent of churches but also can be called into question in juxtaposition to innovative life sciences or cognitive sciences, for example. Against this background, theology is faced with the task of reflecting on and justifying its scientific character. It has to be considered that theology, like social systems, in general, and science, in particular (Luhmann 1992:446–461), is characterised by an increasing differentiation. This differentiation of science implies an increasing specialisation of research, which can also be observed in the field of theology and its sub-disciplines. This research article addresses the question of how, in the face of increasingly specialised research studies, the unity of theology can be justified beyond abstract and sweeping definitions.


Introduction
A pluralisation of religious and ideological convictions is currently taking place in many European countries (Pickel 2017). At the same time, the social significance of Christian churches is diminishing as a result of relatively high numbers of people who have left the churches and because of trends towards secularisation (Taylor 2007). These processes of pluralisation and secularisation also affect the academic status of theology. Its existence at universities, which has been taken for granted for centuries, is not only challenged by religious studies independent of churches but also can be called into question in juxtaposition to innovative life sciences or cognitive sciences, for example. Against this background, theology is faced with the task of reflecting on and justifying its scientific character. It has to be considered that theology, like social systems, in general, and science, in particular (Luhmann 1992:446-461), is characterised by an increasing differentiation. This differentiation of science implies an increasing specialisation of research, which can also be observed in the field of theology and its sub-disciplines. This research article addresses the question of how, in the face of increasingly specialised research studies, the unity of theology can be justified beyond abstract and sweeping definitions.
In a first step, the underlying problem is developed in greater detail: a brief historical retrospective outlines a few selected positions on how theology was founded as a science, each of which involved an examination of the contemporary scientific context. Subsequently, the differentiation of theological disciplines and the specialisation of theological research will be presented as an essential characteristic of contemporary science.
A look at history showed that theology always has to face contemporary demands in terms of its scientific character. At present, processes of pluralisation and secularisation challenge the existence of theology at universities not only against the background of religious studies, which are independent of the churches, but also, for example, in relation to innovative life sciences or cognitive sciences. In this context, an essential point to consider was that theologylike social systems in general and science in particular -is characterised by an increasing differentiation. This differentiation of science implied an increasing specialisation of research, which could also be observed in the field of theology and its sub-disciplines. This article accordingly addressed the question of how, in the face of increasingly specialised research studies, the unity of theology can be justified beyond abstract and sweeping determinations. The present contribution suggested that in this respect a model of research designs developed in religious didactics might prove useful. This model of research design could essentially be understood as consisting of three research dimensions (topics, reference theories and methodologies) that define a research space, in which the research study on the didactics of religion can be located in the three-dimensional space by the research goal as a formatting factor. The three dimensions of this model (topics, reference theories and methodologies), including the research goal, seemed to be broad enough to be tested in other sub-disciplines of theology as well to see whether their research can be more closely defined with them.
In a second step, starting from the didactics of religion, which is a subfield of religious education and practical theology, a model of research design is presented, which was developed in the context of a Delphi study (e.g. Rothgangel & Riegel 2021). In essence, this model of research design can be understood as having three research dimensions (topics, reference theories and methodologies) spanning a research space, where research on the didactics of religion can be located in this three-dimensional space using the research goal as a focusing formatting factor.
Finally, the third part justifies why this understanding of research on didactics of religion, based on the model of research designs, might be of interest for theological research, in general. The three dimensions of this model (topics, reference theories and methodologies), including the research goal, are broad enough to be tested in other sub-disciplines of theology to see whether they can be used to further define their research.
Against the background of an increasing specialisation of theological research, the aim of this study was, therefore, to raise the question to what extent can the potential of a generic model of research designs be transferred to other areas of practical theology, as well as other sub-disciplines of theology. Should this succeed, an inductive path in the determination of the unity of theology could be taken, which takes seriously the current differentiation of theology and specialisation of theological research and could represent a complementary approach to abstract attempts to determine the unity of theology.

Theology as science and the differentiation of theology
In the course of history, theology has had to repeatedly reestablish whether and in what respect it is a science. 1 In recent times, this discussion has led to the question of the unity of theology in view of the differentiation and specialisation of theological sub-disciplines. In the following section, we briefly sketch elementary models of the understanding of theology as a science in a historical review in order to then elaborate the differentiation and specialisation of theological research by way of examples.

Theology as science from a historical perspective 2
It is by no means self-evident that theology is defined as a science. Under the pervasive influence of Augustine 1.The following explanations illustrate that over the centuries, the underlying understanding of science has changed again and again. Against this background, it is not surprising that at present it can be stated, for example, by the philosopher Herbert Schnädelbach, that 'we obviously no longer have a generally binding definition of science' (Schnädelbach 2002:150). Without being able to develop this point in more detail here, especially against the background of the sciencetheoretical controversies surrounding Karl R. Popper and Thomas S. Kuhn, only the following basic idea should be noted at this point: what we want to justifiably recognise as scientific knowledge ultimately depends on a 'family' of criteria that are 'more or less, but always only partially, fulfilled' (Schnädelbach 2002:151) in the various scientific disciplines.
2.For the following see in detail Rothgangel (1999), where, on the one hand, the following examples are explained in more detail and, on the other hand, further examples are presented.
(354-430), it was common up until the High Middle Ages to characterise theology as sapientia (wisdom) and to distinguish it from scientia (science). Whereas the latter deals with earthly and temporal things, the object of theology as sapientia is the eternal; in other words, God as the highest good as well as eternal communion with God, which formed the goal of human life (Köpf 1974:221;Marrou 1982:312-318, 466-470). It was not until the 13th century that this classification of theology as sapientia was profoundly challenged by the emergence of the universities (Leinsle 1995:111-121;Pannenberg 1973:11). It is true that theology was one of the three higher faculties (theology, jurisprudence and medicine). However, its position in the context of the sciences raised the question of the scientific character of theology. Especially under the auspices of an Aristotelian understanding of science, it seemed that theology could not be determined as science, or only to a very limited extent (Pannenberg 1973:227 and 230).
A long-standing solution to this dilemma was formulated by Thomas Aquinas (1225-1274), who took up the Aristotelian distinction between superior and subordinate sciences, and determined theology as a subordinate science (Von Aquinas 1952-1962:Sth I q. 1, a. 2 c). In contrast to the superior sciences, the principles of which can be understood by the intellect, the subordinate sciences obtain their basic tenets from the superior sciences in order to arrive at knowledge for their field on the basis of these principles. In this sense, theology also derives its principles from a higher knowledge as expressed in the divine revelation, that is to say, in the Holy Scriptures or in a summarised form in the articles of faith (Von Aquinas 1952-1962:Sth I q. 1, a. 8 c). Thomas Aquinas' classification of theology as a subordinate science was frequently echoed in subsequent times.
However, details of his approach were already challenged by critics in the Middle Ages. In contradiction to the Aristotelian doctrine of science, Duns Scotus (c. 1270-1308), for example, argued that the highest principles of theology are not universally evident but can ultimately 'only be believed on authority' (Joest 1988:243;cf. Köpf 1974:149). This, however, contradicts the requirement that, almost by definition, the principles received from the superior science must be believed at least according to the evidentia per experientiam (i.e. according to the evidence accepted by all but yet to be proven). He, therefore, considered purely syllogistic conclusions based on the Holy Scriptures as inadmissible. Consequently, theology can be defined neither as a scientia speculativa (Henry of Ghent) nor as a scientia speculativa et practica (Godefried v. Fontaine; Thomas v. Aquinas). Rather, it is a scientia practica, and thus, elaborates a 'knowledge that does not so much aim to develop exact theoretical teachings about God but rather to direct man's striving and action toward God as his highest goal' (Joest 1988:243 This roughly translates to '[t]rue theology is practical and its basis is Christ, whose death is grasped by faith.
[…] Therefore speculative theology belongs in hell with the devil'.
With the Age of Enlightenment and the demand for unrestricted autonomy of reason, however, the scientific nature of theology was once again subject to debate, regardless of whether it was understood as a subordinate science or as scientia practica. In both cases, it was accepted that the principles guiding theology exist by virtue of authority and are thus not evident to common sense (Joest 1988:243). The new model of such scientificity was philosophy and the natural sciences based on it. Following this ideal, Friedrich Schleiermacher (1768-1834) designed the model of a theology as a 'positive' science. According to this model, such a science is characterised by '[the necessity] for the solution of a practical task' (Schleiermacher 1961: §1). With regard to the nature of Christianity, Schleiermacher states that a scientific theology cannot be derived from the idea of the absolute (Scholz 1961:XXVI). Theology, however, can be understood as a positive science, since it: … is the epitome of those scientific knowledge and rules of art without the possession and use of which a coherent government of the Christian church, i.e., a Christian church government, is not possible. (Schleiermacher 1961: §5) Knowledge, according to this understanding, therefore can only be qualified as 'theological' in a scientific sense if it bears a relation to church governance (Schleiermacher 1961: §6). The principles of this governance, however, still remain linked to divine revelation, and thus, bound to an idealistic philosophy.
By the time the natural sciences were established, however, Schleiermacher's definition of theology as a positive science also became suspect, for subsequently all science 'worked primarily, if not exclusively, by determining and analysing the empirically 'given' and as the development of prognostic and pragmatic consequences from this analysis' (Joest 1988:244). Within this setting, a distinction made by Wilhelm Dilthey  between the natural sciences and the humanities proved to be of further significance. If natural sciences seek to explain what is present, the humanities seek to understand it. According to his view, theology appears as part of the humanities, which are concerned with an 'understanding of human expressions of life of the past and their interpretation in the context of the present understanding of human existence' (Joest 1988:245). However, not even this classification finds sufficient justification for the fundamental reference within theology to divine revelation and thus its derivation from sources that are not evident from a rational point of view. This dilemma becomes clear, for example, from the fact that with religious studies, a scientific approach to religion is available, which exists without such recourse and is, therefore, generally recognised as scientific.

The differentiation of theology and specialisation of theological research
The brief historical review has shown that theology must always face anew contemporary expectations of what constitutes a science. At present, however, another challenge seems to have been added with regard to its scientific selfunderstanding, which has an effect on the inner context of theology: it is a characteristic of contemporary science that scientific disciplines are becoming more and more differentiated. While at the beginning of the 19th century, it was still common for professors of theology to lecture on virtually all sub-fields, the designation of a present-day professorship refers to a specific theological subfield.
Currently, theology can be divided, at least in the Germanspeaking context, into the four major subfields of biblical studies, church history, systematic theology, and practical theology, to which other fields, such as religious studies and intercultural theology, can be added (Wissenschaftliche Gesellschaft für Theologie, Fachgruppen, viewed 02 September 2021, from http://www.wgth.de/index.php/fachgruppen). Each of these subfields not only stands for a particular object of research that it examines primarily but also draws on an array of specific methods with which it approaches this object of research study. Biblical studies, for example, use literary methods, Church History historical methods, Systematic Theology philosophical methods and Practical Theology social science methods (Rothgangel & Thaidigsmann 2005). As a rule, the expertise of each theological subfield in its characteristic methods is so great that it can no longer be fully comprehended by colleagues in the other sub-disciplines of theology. As a result, areas of knowledge and competence emerge that are only accessible to one part of theology.
However, this process of differentiation continues within the individual theological subfields. If, for example, the exegesis of Old Testament texts accesses contemporary sources and artefacts, linguistic and archaeological knowledge becomes necessary, which has no bearing on the exegesis of New Testament texts itself. Within systematic theology, when analytical theological treatises use a mathematical form of expression, these forms of representation remain incomprehensible to systematic theologians with a more continental philosophical orientation (Höhn et al. 2021). And within church history, the analysis of sources from the church fathers requires different skills and methods from the study of contemporary historical sources. Finally, practical theology has also differentiated into various sub-disciplines that refer to different issues and examine them using, in part, specific methods. Here, for example, a distinction is often made between homiletics, liturgy, poimenics, catechetics or religious education, or diaconal studies. 3 Furthermore, at least in German-speaking countries, a certain independence 3.A critique of and alternative to this classification, which is oriented to the main activities of pastors, has already been formulated by Gert Otto (1986). Without being able to provide an in-depth discussion of different classifications in the international context, the classification in pastoral care, homiletics and liturgy, faith formation, congregational studies and leadership, and spirituality should be at least mentioned as a current alternative (e.g. https://www.ufs.ac.za/theology/ departments-and-centres/practical-and-missional-theology-home).
http://www.hts.org.za Open Access of religious education in relation to practical theology can be observed, which is in part because of the requirements of the training of religious education teachers for religious education at state schools (Rothgangel 2020;Schlag & Schröder 2020). This trend of religious education becoming independent may be strengthened insofar as, from an international perspective, in quite a few countries (such as England and Sweden) denominational religious education is no longer offered in state schools, so that religious studies, rather than theology, is the primary reference science of religious education.
This differentiation of theology is further driven by the increasing specialisation of research and by competitive research tendencies (promotion of third-party funded research and internationalisation) at universities. In the field of religious education, for example, interdisciplinary collaboration with educational psychology has led to an enormous increase in methodological standards over the past two decades, even in empirical studies of religious education (e.g. eds. Schreiner & Schweitzer 2014). Similarly, the necessity to publish in international journals makes the membership in international academic associations with a focus on religious education more attractive than the membership in national associations covering the entire field of practical theology. Moreover, calls for proposals for research projects in the field of religious education are increasingly designed in such a way that cooperation with empirical educational sciences becomes necessary. However, this diminishes cooperation with other sub-disciplines of practical theology.
This increasing specialisation within the theological disciplines raises the question of the unity of theology and the coherence of the theological sub-disciplines in a new and intensified way (eds. Gemeinhardt & Albrecht 2021; eds. Ritter & Rothgangel 1998;Rothgangel & Thaidigsmann 2005). Unifying definitions of the subject matter of theology, such as 'theology as a science of God' (Pannenberg 1973:299) or as a 'rational reflection about what we take to be holy, that is, of ultimate importance for its own sake' (Griffin 1989:VIII), are very abstract and insufficiently reflect contemporary research practice. It seems promising to us to take a complementary inductive path in determining the unity of theology, which takes the current differentiation of theology and the current research challenges as the starting point of reflection.

A model of research designs in religious didactics
The differentiation described above continues even within religious education. In the German-speaking world, amongst other things, the so-called Programme for International Student Assessment (PISA) shock and the resulting increase in interdisciplinary collaboration between subject didactics and educational psychology have led to a strong focus on the school setting within the religious education research, which can also be referred to as religious didactics (e.g. Riegel 2019). The term 'religious didactics' here refers to discourse in many parts of Europe (such as the German-and Frenchspeaking contexts, the context of Slavic and, to a large extent, Scandinavian languages), which expresses the scientific reflection of teaching and learning, the school context often being the main focus (Rothgangel & Vollmer 2020). As in other didactics, the question arises regarding what is typical and what the specific standards of its research are, for example, in the context of reviewing applications for external funding? From a theological perspective, applications for funding in the didactics of religion may appear to be deficient in terms of other academic sub-disciplines of theology, and from a pedagogical-psychological perspective, deficient in terms of methodology.
In order to determine the specifics of didactics of religion in view of an increasingly specialised research, we have therefore made it our task to elaborate elementary research designs of this discipline.
According to the definition of the 'Gesellschaft für Fachdidaktik' (Association for Subject-matter Didactics), a research design is defined as follows: [T]he totality of all content-related, methodological and organizational aspects of research which can be described in the planning, implementation, evaluation and processing of results of a didactical research project [...]. This includes, among other things, theoretical relevance, interest in knowledge, methods of investigation and evaluation, and procedures for using the knowledge gained'. (GFD 2015:2) In order to identify such research designs, we first developed a preliminary model of the basic dimensions of such designs . This model elaborated on the previously cited definition of the GFD by relating it to the discourse on research designs (f.i. Creswell & Creswell 2018;DeForge 2010;Gorard 2013). We then invited nine wellknown colleagues within the field of religious didactics to reflect the question whether and how their particular field of research might represent a distinct research design of religious didactics on the basis of this model . These reflections led to reformulate our model  and describe the profile of eight such designs (Riegel & Rothgangel 2021a). Afterwards we initiated a Delphi study on the model (Riegel & Rothgangel 2021b). As a first step, we invited all colleagues of the German-speaking scientific community of religious didactics (Austria, Germany and Switzerland), who at least hold a PhD degree to evaluate both the model and the tentative research designs in an online questionnaire. Open questions offered the opportunity to suggest corrections on the model or additional research designs. The response rate was very high at N = 75. The second step in the Delphi study presented the saturated model and designs to the colleagues and asked them whether they can approve them.
The first round of the Delphi study, however, already brought about an overwhelming support of the basic structures of the proposed model. This allows us to describe the basic outline of this model in this study. In accordance with the definition of the GFD, the model of this study comprises three basic dimensions that characterise research designs in religious didactics: topic, theory of reference and methodology. The research topic designates the class of objects that the projects of a research design focus on. The theories of reference stand for the scientific disciplines and their systems of explanation and understanding from which the projects of a research design are fed. Finally, the methodologies capture the methodological approaches used by the projects of a research design. Each of these dimensions has the potential to structure the religious didactical field of research in a comprehensive manner. The topical dimension, for example, characterises the objects that are normally under scrutiny in this discipline. According to the Delphi study, the category contents of learning, teaching and learning processes, teachers, pupils, religious education as a school subject and its contexts, and theories about religious education cover the German field of religious didactics quite comprehensively. In terms of reference theories, religious didactics seems to rely on theology, educational studies, psychology, sociology, cultural studies and philosophy, while religious studies are regarded as of minor importance by the German colleagues. Regarding methodology, the relevant categories include historical, philosophic-hermeneutical, comparative, empirical (both qualitative and quantitative) and practice oriented.
According to the study model, the interplay of these three dimensions clearly defines the profile of a concrete research design in the didactics of religion. The character of this interplay, which is typical for each research design, is determined by the research goal of each design. Like the research question on the level of individual research projects and the interest of discovery ('erkenntnisleitendes Interesse', see Habermas 1994) on the level of scientific disciplines, the research goal defines in what way the projects within one research design relate to the three basic dimensions of topic, reference theory and methodology. If these three dimensions demarcate the space within which all research designs can be found, the research goal indicates the specific location of a particular design in this space. Being informed about a design's basic research goal, one knows which topics are addressed by this design, which theories back up its considerations, and which methodologies are relevant and in which respect.
Finally, we suppose that the form of a research design is also influenced by the context in which the research study is conducted (what also applies to this essay, which is shaped by the German-speaking context). For example, examining religious education at state schools might be shaped by the cultural environment in which it takes place. In a culturally Christian or Islamic environment, the willingness to participate in a study on religious teaching and learning may be higher than in a culturally secular environment. In this regard, our model comprises a contextual dimension. It defines the sphere in which research in religious didactics takes place, and therefore, might determine the concrete profile of research designs in religious didactics. In the Delphi study that we have described previously, the German colleagues regard the legal regulations on religious education as a school subject, the financial and personal resources of university research institutions, the chances of obtaining third-party funding for projects, or the institutional context at the respective university (e.g. centres for teacher education) for very influential if research in religious didactics is concerned, while the religious-cultural atmosphere within the society, the churches or other religious communities as stakeholders, the numerical distribution of religious communities in society or the existence of a national institute of excellence devoted to religious education are of minor relevance.
To summarise, our model of research designs comprises three basic dimensions that delineate the space in which this research study in religious didactics is carried out: topic, reference theory and methodology. By applying these three dimensions, all research in this scientific discipline can be assessed. Within this space, there are particular research goals that determine the interplay of the three dimensions, and therefore, bring about distinct research designs. In consequence, each research design of religious didactics represents a characteristic relationship between topics, reference theories and methodologies, which is expressed in its research goal. Finally, that space, which is delineated by the research dimensions topic, reference theory and methodology, is embedded in a contextual sphere, which influences the realisation of these designs. According to the first step of the Delphi study, this model is comprehensive enough to enable framing of the discussion on particular research designs in religious didactics.

The potential of the generic model of research designs for theology
Taking a perspective from beyond religious didactics, the presented model seems to be rather generic. Its basic dimensions topic, reference theory and methodology should be also relevant in other theological sub-disciplines. The same seems to be true for the research goal, because in other disciplines of theology the respective research goal should also enable a contextualisation of research designs in the three-dimensional research space.
The basic potential of this approach is that in this way a more differentiated coverage of theological research is made possible than is achievable through abstract definitions of the subject matter. In order to avoid being misunderstood:, abstract determinations of the subject area are necessary and allow for a rough orientation of theological research. However, they do not do sufficient justice to the current differentiation of theological research, as the following example based on religious didactics will demonstrate: in abstract terms, the subject area of religious didactics can be defined as the theory of school-related religious education. On the basis of these considerations, it is evident that the general definition of 'school-related religious education' in the study model of research designs can be captured in a more nuanced way not only on the basis of the topics (contents of learning, teaching and learning processes, teachers, pupils, religious education as a school subject and its contexts, and theories about religious education) but also on the basis of the methodologies and reference theories. Previous definitions of subject areas do not sufficiently take into account that the respective methodological approach and the reference theories used in each case crucially determine the description and interpretation of the respective subject area.
If one applies this approach to other areas of practical theology as well as to other sub-disciplines of theology, the present model of research designs could also facilitate a sophisticated assessment of research in the various sub-disciplines of theology. For example, within the framework of a Delphi study, it could be ascertained which topics, reference theories and methodologies determine the current research in New Testament scholarship and which research designs can be located here. On the basis of such a survey of research in the various sub-disciplines of theology, it could be ascertained in a comparative way which topics, reference theories, and methodologies are common to all theological sub-disciplines and which aspects of these three research dimensions differ characteristically between the sub-disciplines.
Furthermore, the concrete research designs of the theological sub-disciplines and their respective positioning in the threedimensional research space deserve attention. Here again, it can be fruitful to observe where the research designs of theological sub-disciplines overlap and which research designs are specific to a theological sub-discipline. In this way, it can be determined from the bottom up, as it were, whether and in what respect the present model and the resulting research designs of theological sub-disciplines result in a path to establish the unity of theology in a dialectical way that does justice to both the commonalities and the differences of the theological sub-disciplines. Beyond the abstract definitions of the subject matter of theology as a science, a more differentiated picture of theology as a science could be gained in this manner, which reflects the current differentiation of the various sub-disciplines of theology, as well as the specialisation of theological research.

Concluding remarks
A look at history showed that theology always has to face contemporary demands on what characterises a science. At present, an essential point to consider was that theologylike social systems, in general, and science, in particular -is characterised by an increasing differentiation. This differentiation of science implied an increasing specialisation of research, which could also be observed in the field of theology and its sub-disciplines. This article accordingly addressed the question of how, in the face of increasingly specialised research, the unity of theology can be justified beyond abstract and sweeping determinations. The present contribution suggested that in this respect a model of research designs developed in religious didactics might prove useful. This model of research design could essentially be understood as consisting of three research dimensions (topics, reference theories and methodologies) that define a research space, in which research on the didactics of religion can be located in the three-dimensional space by the research goal as a formatting factor. The three dimensions of this model, including the research goal, seemed to be broad enough to be tested in other sub-disciplines of theology as well, to see if their research can be more closely defined with them. Should this succeed then a new approach to justifying the unity of theology could become available, which is able to take into account the current differentiation of theology.