We Have Big Data, But Do We Need Big Theory? Review-Based Remarks on an Emerging Problem in the Social Sciences

Big data represents a significant challenge for the social sciences. From a philosophy-of-science perspective, it is important to reflect on related theories and processes for developing them. In this paper, we start by examining different views on the role of theories in big data-related social research. Then, we try to show how big data is related to standards for evaluating theories. We also outline how big data affects theory- and data-based research approaches and the process of theory building. Discussions include a summary of lines of reasoning, limitations, and a proposal for future developmental steps.


Introduction
"Big data" has undoubtedly reached the social sciences (e.g., Foster et al. 2016Foster et al. [2020]]; Jemielniak 2020).In general, the term describes "the collection, processing, analysis and visualization associated with very large data sets" (Emmanuell and Stanier 2016, 1).In particular, big data is characterized by facets such as volume (covering enormous quantities of data), velocity (creating evidence in real time), variety (integrating different structuring approaches), exhaustivity (capturing a full sample), resolution and identification (differing in granularity and addressing multiple entities and processes), relationality (linking multiple data sets), extensionality and scalability (adding new data and expanding in size), veracity (containing uncertainty and errors), value (extracting many different insights), and variability (shifting meaning in relation to the context) (Kitchin and McArdle 2016).In the field of social sciences, big data has numerous implications for exploration techniques, sample design or creation, measurement and data collection, data integration and combination, data validation and quality assessment, error frameworks, statistical analyses, and interpretation as well as automated reporting and publishing. 1 These and similar implications raise many critical questions and unsolved problems in the methodology or methods of the social sciences related to statistics, measurement and testing, or computer applications such as machine learning and artificial intelligence. 2The potential of big data is also apparent in the fact that new subdisciplines are currently emerging in the social sciences that are based on big data, including "data science methods" (Foster et al. 2016(Foster et al. [2020]]), "computational social science" (McLevey 2022), and "digital humanities" (Drucker 2021).From these significant developments emerges the problem of whether changes in the methodology and methods of a science also produce changes in other fundamentals of this science.

Objectives of the Study and Research Questions
Based on a comprehensive review of literature in the field of social sciences, our objective is to collect, structure, and reflect ideas and concepts on the role of theories and theory building in relation to big data.Theories are propositional systems about social phenomena, and their validity is tested by confronting them with evidence and relevant data.First, we start by asking 1 For a helpful comprehensive, detailed, and critical introduction to innovative methods, see Hill et al. (2020).
whether there is a need, in the field of philosophy of science, to focus on big data and theories.Second, we examine whether big data has implications for the design or formulation of theories.Third, we investigate whether there are problems related to standards for evaluating theories based on big data.Finally, we seek to determine whether big data has significant potential in the discovery and building of theories.Since big data is not yet a well-developed research field in the social sciences, especially when considering a theoretical perspective, we take an exploratory problem-sensitive approach to uncover open questions or unsolved problems for future investigations.

Big Data, Philosophy of the Social Sciences, and Big Theory
From a philosophy-of-social-science perspective on big data, some researchers have discussed a paradigmatic shift toward "new empiricism" (based on a stronger focus on data evidence; Arbia 2021) or "digital positivism" (related to computer-generated evidence about the world; Fuchs 2017).More specifically, Chin-Yee and Upshur (2019) have identified three major philosophical problems associated with big data: a) the epistemological-ontological problem arising from the theory-ladenness of big data, b) the epistemological-logical problem resulting from the limitations of algorithms as well as reliability and interpretability issues, and c) the phenomenological problem of the irreducibility of human experiences to data.Recently, Pietsch (2021) has discussed the methodological dichotomy between inductivism and hypothetico-deductivism and argued that successful big data algorithms are based on variational induction in the tradition of Mill's methods. 3Cabrera (2021) has stressed that using correlations based on big data for predictive purposes is dangerous unless some plausible causalnomological connection undergirds these correlations.Others have dealt with big data ethics and found problems regarding privacy (big data traces life and makes it transparent), propensity (big data increases the likelihood of random findings based on incidental co-occurrences, which might have negative consequences for people), and research ethics (big data collects data without informed consent) (Zwitter 2014).All of this work essentially confirms the relevance of big data to the philosophy of social science.
As methods and evidence play a larger role in social sciences through the development of big data, the question inevitably arises of whether this impacts another essential fundamental of research and philosophy of science, namely, theories.At present, there are different assumptions on the role of theories in 3 Pietsch addresses the essential questions of whether correlations are replacing causality, whether theories are in jeopardy, and whether big data will lead to an entirely new science.relation to big data.For example, Mazzocchi (2015Mazzocchi ( , 1250) ) has wondered whether big data could be the end of theory in science: "Analyzing vast volumes of data will yield novel and often surprising correlations, patterns and rules.Inasmuch as the latter emerge through a bottom-up process based on inductive processes and statistical manipulation, no theory is apparently required."However, others like Wise and Shaffer (2015, 9) are convinced that theory matters more than ever in the age of big data because it provides guidance about a) which variables to include in a model on data structures, b) which confounds, subgroups, or covariates influence the data, c) which results to attend to, d) how to interpret complex results, e) how to apply results, and finally f) how to generalize results to other settings.From a natural science perspective, others have gone so far as to assert that "big data need big theory too" (Coveney, Dougherty, and Highfield 2016), that is, a scientific theory that describes and explains phenomena related to big data.
Following these different assumptions, the question is what big theories or big data-related theories could be and whether such concepts would be viable in the social sciences.Are big data-related theories just new theories or other types of theories like, for example, open system approaches?Are these theories extended core theories or changes in the peripheral areas of theories?Perhaps big data means that the social sciences should pay less attention to theory confrontation or replacement and more to unified approaches in science and theory integration (or even completion) to create more complex theories that can deal with complex big data.Another approach could be to focus more on process theories because big data can often be collected over a longer period.If big data depicts many layers within social entities such as individuals, groups, institutions, or societies, then something like meta-theories would be required that create a connection between (hierarchically organized) micro and macro areas.Alternatively, it may also be relevant to push pluralistic approaches that, for example, consider alternative explanations or competitive theories as well.Existing approaches on data or evidence-based theory building in the social sciences do not give sufficient answers to these and similar questions; therefore, they will also be important for future investigations (e.g., Shoemaker, Tankard, and Lasorsa 2004;Reynolds 2007;Swanson and Chermack 2013;Jaccard andJacoby 2009 [2020]). 4 A first preliminary answer to these questions could be that big data-related theories might be "system theories" concerning a large set of hypotheses on complex social systems (e.g., Dabbaghian and Mago 2014).The social sciences have produced multiple complex system theories, for instance, on 4 However, it must be mentioned that the frameworks for theory construction proposed by Jaccard andJacoby (2009 [2020]) also contain approaches on mathematical modeling and simulation that are relevant to theory-building processes regarding big data.
human development (Bronfenbrenner 1994), health (e.g., Sturmberg andMartin 2013), or work (Alter 2013).A comprehensive overview of new developments in the field of system theory related to "complexity theory" (as an array of overlapping and interacting areas such as system theories, complex adaptive systems, and chaos) in social sciences is given by Turner and Baker (2019).However, a philosophy of the social sciences perspective has revealed that such theories "have limited use in the study of society and that social processes are too complex and particular to be rigorously modeled in complexity terms.Theories of social complexity are shown to be inadequately developed, and typical weaknesses" (Stewart 2001, 323) include the misuse "of complexity theory in alliance with systems theory as a general and dominant metatheory for the social sciences," "the myth that all or most social processes can usefully be quantified in mathematical terms," the uncritical use of "metabiological, organicist (and organismic) model of social systems," and the problem that "theories of social complexity are parented by a limited range of social philosophies that are each subject to ongoing social debate" (Stewart 2001, 329-30).The notion that we need larger or more complex theories to deal with big data can also be questioned in another way.Additional evidence from big data creates more pressure on theories.From an analytical perspective, it can be argued that big data is not about the size of a theory but about the extent to which the data allows us to reject alternative theories.In this sense, big data does not imply a larger theory but rather a smaller set of competing theories that fit the available data. 5 From a social science databased perspective, this assumption can be supported because big data delivers additional information on rival independent and intervening variables, control variables, and antecedent and consequent variables (see the elaboration model of theory-based data analysis by Aneshensel 2002Aneshensel [2013], 12)], 12).In this sense, big data could contribute to the monopolization of theories in the social sciences and lead to a reduction of theoretical plurality.
Overall, the relationship between theories and big data seems unclear and controversial and requires further analysis.It is likely that big data does not produce a disruptive paradigm change for theories in the social sciences but rather incremental gradual shifts.

General Big Data Implications for Theories
At first sight, it could be concluded that big data has no significant implications for theories in the social sciences because it only means more of the same (i.e., more data).This is evidenced by the fact that significant theoretical perspectives are missing from important contributions on big data and social research (e.g., Woo, Tay, and Proctor 2020).However, merely having more data for developing and testing theories does not seem to be the only general implication of big data for theories within the social sciences.Maass et al. (2018) have stressed the necessity to distinguish between (more inductiveorientated) data-driven and (more deductive-orientated) theory-driven research when using big data.Luo et al. (2019) have pointed out that, on the one hand, big data could stimulate theory building by producing new insights on phenomena through data mining (i.e., finding patterns in data by using statistical methods, database systems, or machine learning), and, on the other hand, theory could help to structuralize big data sets by selecting or combining data segments based on a theoretical perspective.Among other things, Haslbeck et al. (2021) have emphasized the role of structured "data models" as an essential link between data and (formalized) theories.
Considering and integrating important elements of these authors' arguments and assumptions, we depict in Figure 1 the relationship between big data and theory in the social sciences.Big data allows a more data-driven research process.In such a process, a real phenomenon produces a large amount of data.In this data, patterns of relationships between data segments are identified, for example, by applying statistical methods such as correlational analysis.Structuring this data creates a data model that offers an organized representation of data.This representation can partly or as a whole be converted into hypotheses that are embedded in a theory.Big data can also play a role in a theory-driven research process.Here, the starting point is a theory, its hypotheses, and related operationalized variables.Based on these variables, new data is collected or existing data is mapped.A test is then performed in which a theory-based model is fitted with the data and related data models.When this comparison is positive, the related theory is positively evaluated or confirmed.If the theory does not fit the data, it is rejected.
However, such data-and theory-driven approaches are not new in social research.Using a data-driven approach and finding (correlational) structures in data to stimulate theory building is found in, for example, traditional exploratory and confirmatory factor analysis (Reio and Shuck 2015).Theorydriven approaches are applied, for instance, in traditional structural equation modeling (Schumacker andLomax 1996 [2010]). 6It seems that more data does not lead to revolutionary research approaches but rather provides fundamentals for gradually expanding and optimizing already existing research processes in social research and related theory-building activities.
Others see big data not as a slowly appearing phenomenon but as a threat to advances in the social sciences and associated theories.More data could also lead to more bad data: having more data may generally contribute positively to the progress in the social sciences as theories can be tested more often (with multiple evidence) and be more comprehensive (with greater depth and breadth) but only insofar as it is good (or valid) data.Scholz (2017, 27-34) pointed out big data pitfalls, noting that "big data will not translate into useful observations by means of big data" and that "any type of data […] is subjective and big data especially are often collected with a certain intent and often repurposed for different goals."He also highlighted the complexity barrier, which "describes the situation wherein the effort of gaining scientific insight from a research field rises exponentially when approaching a certain threshold of complexity" and argued that "taken out of context, big data lose their meaning."Following these arguments, bad big data may also lead to bad new theories.Of course, the problem of bad theories existed before big data, and good theories can make bad predictions. 7o avoid bad big data and its negative consequences for theories in the social sciences, existing and newly developed theories must be able to provide support in data structuring, data selection, and related decision-making.In this sense, a reciprocal relationship between theories and big data is given, which also means that data-and theory-driven approaches to big data do not exist independently of each other.Thus, big data may seem especially relevant to research activities in which data-and theory-driven stages are systematically combined or integrated.Such approaches exist in the social sciences, for example, as "design-based research" (iterative design-and-test cycles for developing interventions to address problems) or "mixed method research" (a combination of exploratory qualitative and testing-related quantitative research) (e.g., Ryu 2020).For example, Reimann (2016) has tried to link big data-related learning analytics to design-based research.However, except for rather individual suggestions, the role of big data and related theories in such integrative or unified research approaches is still vague.Above all, it is important to combine unified or integrated approaches in the philosophy of science with similar research approaches.Such integration of research approaches also existed long before big data (Edmonds and Kennedy 2013;Schurz 2013).
In addition, to avoid bad big data and its negative implications for theories in the social sciences, big data has to be evaluated in terms of its importance and quality by establishing data-evaluation and decision-making activities concerning the certainty of the evidence, the magnitude of benefits and harms, considerations of resource use, feasibility, acceptability, and equity as well as values and preferences (Djulbegovic and Guyatt 2017).Such a decisionmaking process regarding big data is influenced by numerous factors such as contractual governance, big data tool availability and capabilities, collaboration and knowledge exchange, or process integration and standardization (Janssen, van der Voort, and Wahyudi 2017).This situation might also lead to an expansion of traditional data-cleaning activities and primary and secondary traditional standards on data quality (objectivity, reliability, validity, fairness, etc.) in the social sciences to other standards like availability (accessibility, timeliness), usability (credibility), or relevance (fitness) (Cai and Zhu 2015;Ilyas and Chu 2019).Whether considering such additional standards of data quality would have a positive or a negative effect on theories in the social sciences is still an open question.For example, having more data and additional or stricter standards could contribute to solving problems with the discovery and testing of theories in the social sciences, such as the "replication crisis" (concerns about the credibility of research findings) or "publication bias" (when the outcome of a study biases the decision for publishing) as more (also high-quality) evidence is available that could be a repetition of existing findings or could not be ignored for publishing (Wagner 2022).Here, too, there are already other existing proposals in the social sciences about the replication and publication bias problems that make it possible to handle the problem without big data, such as standards for publication (Tincani and Travers 2019).These and other similar standards are related to data and how to handle it, but this leaves open the question of whether changes in standards apply not only to methods but also to theories.

Big Data and Standards for Evaluating Theories
Traditionally, we use the following standards for evaluating theories in social sciences (Prochaska, Wright, and Velicer 2008, 565): Clarity (the theory has well-defined terms), consistency (the theory's components do not contradict each other), parsimony (the theory explains the phenomenon in the least complex manner), testability (the theory's propositions generate empirical evidence and can be falsified), empirical adequacy (the theory explains why something happened and when something will happen), productivity (the theory reveals new phenomenon), generalizability (the theory generalizes to other situations, places, times), integration (the theory combines a set of constructs in systematic and meaningful patterns), utility (the theory provides service), practicability (a theory-based intervention demonstrates significant efficacy), and impact (the theory has effects in a combination by reach x efficacy x number of behaviors changed).
However, these traditional standards must be re-evaluated if we consider the fact that there are different types of big data-related theories that have to meet different requirements.For example, when focusing a complex system on big data-related theories, additional general constituent properties must be kept in mind, such as holistic systemness, the integration of structural and functional hierarchies, the coordination of dynamics on multiple time scales, various kinds and levels of complexity, encoding and sending/receiving information, or the implementation of regulation subsystems to achieve stability (Mobus and Kalton 2015).We can treat such constituent properties of complex system theories as standards for their evaluation because the absence of these properties will lower the quality of the theory.Alternatively, with big data-related theories as (machine-)learning systems, we must consider other standards for evaluating theories, for example, interpretability (the degree to which the model can be interpreted by humans), robustness (the ability of a model to handle missing data and still make good predictions), or effectiveness (the degree to which the algorithm detects context changes) (Siebert et al. 2022).When considering computational models, standard-based evaluation activities must concern, for instance, model verification (internal consistency of the model), input validation (representation of the target in a model), process validation (representation of real-world mechanisms within a model), and output validation (fit of the model or its ability to predict future states of a target) (Gräbner 2018).The existence of multiple relevant standards for big data-related theories in the social sciences creates consequential problems for theory building (see Figure 2).
First, there is the problem of standard incompatibility.For example, according to traditional standards for the evaluation of theories, parsimony (of elements and relationships) is important.However, theories on complex systems are highly elaborate and not at all parsimonious as they cover many elements and relationships to produce a holistic or system-like picture of a social phenomenon.To deal with the problem of standard incompatibility, the social sciences could rely on meta-standards that relate to general and superior criteria that can be included in the evaluation of theories and theory development processes.When the standards are incompatible, one such metastandard could be that theories should be built and tested from simple to complex versions in a step-by-step procedure.Thus, standard incompatibility is eliminated as simple (more parsimonious) models are not incompatible with complex (less parsimonious) models because complex models arise from simpler models.In this example, a meta-standard could be that theories should be developed and tested from simple (parsimonious) to complex (nonparsimonious) versions that are built on each other.An example of simple and complex versions of a theory within the social sciences (not focused on big data) is the Cognitive-Affective-Social Theory of Learning in Digital Environments (CASTLE) model developed by Schneider et al. (2022), which is based on a simpler version by Moreno (2006). 8Overall, and despite these examples, the role of meta-standards in handling standard incompatibilities in big data-related theory development and testing still requires further investigation.
Second, there is the problem of standard softening when multiple big datarelated theories have to be integrated at different stages of theory development.For example, when combining or integrating theories from different subject areas as a necessity in a big data situation, some theories are likely strong theories with significant evidence whereas others are weak and without sufficient evidence.The question is now what happens to a complex big datarelated theory when some parts have sufficient evidence and others do not.A possible solution to the problem of differently developed theories and related standard softening might be the use of Bayesian approaches (Gill 2002(Gill [2014]]).They enable the use of probability as a measure of uncertainty, which makes it possible to integrate variables and relationships with strong or weak empirical evidence (e.g., Uusitalo 2007).Bayesian approaches are probabilistic graphical models containing a set of variables and their conditional dependencies.For example, Humphreys and Jacobs (2015) have presented a Bayesian framework for the integration of quantitative and qualitative data at different levels or weights of evidence.A recent example of the use of the Bayesian approach in the field of social sciences was provided by Alvarez-Galvez (2016) regarding the relationship between socioeconomic status and health.However, whether Bayesian approaches represent a sustainable helpful tool for theory building and testing is still discussed (e.g., Jones and Love 2011).
Third, the different levels of progressivity are problematic when new and established phenomena and new and established theoretical assumptions are addressed simultaneously.In such a situation, we can handle established phenomena with established or new theories or handle new phenomena with established or new theories (Zahra 2007).In these cases, we need a standard for whether to be more or less progressive in big data-related theory building.A possible solution to this problem could be to focus on comparing multiple models when developing and testing theories.Multiple models could then contain old and new theories as well as old and new phenomena.These multiple model tests and other similar ones are established in many fields of social sciences (e.g., Jang 2008).Another solution to make a decision concerning progressivity in theory building is related to the variability of empirical findings.Yang (2002) has suggested examining the variability of effect sizes (i.e., a measure of the magnitude of an effect or relationship) for the variables of interest.If there is no significant variability, the focus should be on an old theory.If there is significant variability, moderators or interaction effects should be identified.If they are significant, a new phenomenon should be included in an old theory; if they are not significant, theory building should be guided by relying on new variables and new theories.However, to the best of our knowledge, neither multiple model tests nor a focus on effect variability have been applied in the context of big data in the social sciences.
Fourth, there is the problem of the existence of different types of theories when building big data-related theories.Big data is often based on hybrid data from different temporal, local, institutional, and other sources.What is true for data might also be true for theory and theory building: some big data-related theories might be "hybrid theories" in which different types of theories are integrated.According to Svejvig (2021), a "hybrid theory" is a combination of two or more types of theories.These include descriptive theories (about how something is), predictive theories (about what will happen if something occurs or an explanation for why something occurs), prescriptive theories (about what to do to achieve a certain goal), and practice theories (about locally situated actions).The problem is that these different types of theories are associated with different goals and different standards for evaluating them.For example, Miller (2010) identified five standards for evaluating practical (evaluation) theories (operational specificity, range of application, feasibility in practice, discernable impact, and reproducibility) that are not compatible with standards for evaluating other types of theories, such as descriptive or predictive theories.There might be different solutions to this problem.Other types of theories may be used as a trigger for generating new ideas for theory development without changing the original type of the theory in focus.For example, in the field of social sciences, Astleitner (2018) used descriptive and explanatory motivational theories to build a prescriptive instructional design theory on multidimensional engagement in learning. 9Alternatively, theories can be translated into other types of theories.For instance, Funnell and Rogers (2011) presented the concept of practical "program theories" (about how an intervention results in outcomes) in which different descriptive, prescriptive, and practical theories are integrated.In addition, it may be possible to include descriptive and prescriptive elements in the same theory.For example, Renkl (2014) proposed a theory of example-based learning containing both descriptive and prescriptive elements.However, overall, the problems encountered by hybrid theories in the context of big data have not yet been analyzed in full detail in social sciences.
Fifth, the existence of multiple paradigms and multiple disciplines in big data-related theories based on different areas of society as well as scientific disciplines poses a problem (e.g., Hu and Zhang 2018).Traditionally, in social science, many researchers assume paradigm incommensurability (Kuhn 1962) due to differences in ontology, epistemology, methodology, or views on human nature that would not allow deriving theories on data from different sources embedded in different paradigms.Nonetheless, theories from different paradigms can arguably be integrated into a unified approach based on a multiparadigm perspective without integration or serve as a new domain for developing a new theory (Schurz 2013;Wang and Segal 2014;Zahra and 9 Prescriptive theories in the field of instructional design contain principles for enhancing learning (and development) through instructional activities.For example, according to Astleitner (2018), such a principle can be as follows: In order to stimulate intrinsic motivation in the classroom, promote fantasy and curiosity by establishing playful activities and discovery learning.Newey 2009).A similar situation is observed from an interdisciplinary perspective in social sciences (e.g., Opp 2009).Approaches to solving the problems resulting from multiparadigm or multidisciplinary big data rely on the assumption that different theories can have a multiparadigmatic or multidiscipline perspective.At least for multidiscipline perspectives, such theories can be found in social research, notably an interdisciplinary theory of coordination (Malone and Crowston 1991), an interdisciplinary model of school absenteeism (Kearney 2008), an interdisciplinary model of consumer trust (Love, Mackert, and Silk 2013), and an interdisciplinary privacy and communication model (Bräunlich et al. 2021).Such theories could be used as models to develop interdisciplinary theories based on big data.Another approach might be to apply methods of theory building that make it possible to build multiparadigm and interdisciplinary theories.Such approaches exist in metaparadigm perspectives (Gioia and Pitre 1990), multiparadigm simulation methods (e.g., Mykoniatis and Angelopoulou 2020), and the development of interdisciplinary theoretical frameworks (e.g., CohenMiller and Pate 2019).These approaches have not yet significantly been used and tested in the context of big data and social sciences.
In summary, it must be emphasized that many of the abovementioned problems faced in evaluating theories (standard incompatibility, standard softening, levels of progressivity, hybrid theories, and multiple paradigms/ disciplines) are not new in the social sciences.These problems all existed before big data and have been dealt with accordingly, although without an explicit big-data perspective (e.g., Christian et al. 2019;Magnani and Bertolotti 2017;Repko andSzostak 2008 [2021]).

Big Data as a Source for Building Big Theories Based on Data Mining
Although these questions remain open and many themes on big data have long been discussed in the social sciences without big data, more evidence may enable the evaluation of theories in a more sophisticated way, especially using systematically evaluated and structured big data.In this way, big data is an important source for the evaluation of theories that is generally related to the building of theories in social sciences: a negatively evaluated theory is redesigned or eliminated to allow new theories to appear.Nevertheless, there is also a more specific way that big data can change theory building in the social sciences.
Big data allows for the identification of social phenomena that would not be discovered by human observation or creativity alone, such as complex population dynamics (e.g., Turchin 2003).Especially, more or less intelligent data mining plays a central role as a process of transforming raw data into useful information or knowledge.Kar and Dwivedi (2020) have shown that text mining (e.g., topic modeling or summarizing opinions), network mining (e.g., flagging noticeable deviant events or behaviors), and image mining (e.g., extracting patterns from groups of images) can identify patterns that deliver fundamentals for theory development.In social sciences, open-source tools for data mining are available, such as R (https://www.r-project.org),WEKA (https://cs.waikato.ac.nz/ml/weka/), and ORANGE (https://orangedatamining.com).For example, Tomasevic, Gvozdenovic, and Vranes (2020) have used data mining with large datasets and machine-learning techniques from artificial intelligence in the field of formance prediction.Safron and DeYoung (2022) have focused on complex approaches for modeling persons that might be used in computational psychiatry.
They have based their model on probabilistic descriptions of patterns of emotion, motivation, cognition, and behavior.A sophisticated approach to using big data tools for theory building in social sciences was proposed by Shrestha et al. (2021).They used and tested an induction approach supported by a machine learningbased algorithm comprised of different stages, including the division of data randomly into two samples, the identification (via data-mining techniques) of comprehensible and robust associations within a first sample, the building of a theoretical explanation, and the testing of hypotheses in the second sample.This procedure corresponds to traditional methods of cross-validation and relates to the philosophy-of-science problem that data used to build a model cannot play a role in confirming the model's predictions (De Rooij and Weeda 2020;Steele and Werndl 2020).Overall, however, a conclusive test about whether such approaches are less, equally, or more effective in theory building than traditional approaches is still missing.
There are also counter-arguments against using such big data tools for theory building in the social sciences.Foster and Stine (2004) have questioned the need for modern data-mining techniques in theory building.They found that traditional statistical regressions resulted in better or equally predictive models of bankruptcy than recently developed data-mining tools.Others have argued that focusing on big data is not necessary because big data can also be broken down into smaller datasets that can be handled with conventional analysis techniques.For example, traditional statistical cluster analyses enable the reduction of large samples by identifying similar groups of individuals, and statistical factor analyses support the reduction of numerous observed variables to a few underlying constructs.The results produced by reduced datasets can then be combined in meta-analyses (i.e., delivering statistics resulting from the combination of multiple scientific studies) (Cheung and Jak 2019).Such meta-analyses have been shown to support the development of scientific knowledge and theories as they increase the precision of a research paradigm by clarifying constructs and their relationships, finding mediators and moderators, and supporting consensus building (Chan and Arvey 2012).However, what might be clear to social scientists is not to philosophers of social science.For example, many social scientists assume that statistical methods such as cluster or factor analyses produce (results as evidence or) data.Others think that in such a case, an abductive operation must be considered that distinguishes in more detail between "selective abductions" (selecting an optimal candidate from possible explanations) to "creative abductions" (introducing new theoretical concepts and models) (Schurz 2016).
Another possible limitation concerns the integration of complex micro-and macro-data into one unifying theoretical approach in a clean relationship based on micro-micro links.For example, Raub, Buskens, and Van Assen (2011) have discussed how micro-macro links have to be conceptualized and used to model micro and macro models in the field of sociology.From a theory-building perspective, these authors have also examined the problem that theoretical approaches often focus exclusively on one hierarchical level of a phenomenon (e.g., the micro level) without having valid assumptions for other levels (e.g., the macro level).Additionally, including micro theories in micro-macro models produces a problem for theory testing as it "leaves the question open [as to] how much priority should be given to empirical tests and to the empirical corroboration of micro-assumptions when the focus is on macro-outcomes" (17).Others, like Van den Berg and Van der Klaauw (2001), have combined micro and macro unemployment data using complex mathematical modeling alone.However, innovative and significant theoretical perspectives on important social or individual factors based on decades of social research on unemployment are missing (Wanberg 2012).This lack or scarcity of theory research corresponds to traditional exploratory research approaches in which no theory is available (e.g., Brashear et al. 2006).
Overall, the situation of theory building in the social sciences is heterogeneous, and big data and related intelligent data mining tools a) are not at all used for theory building, b) are not necessary because alternatives are available for theory building, c) are used without significant benefit, or d) are used without demonstrating superiority over traditional methods of theory building.However, data mining seems to be a very promising approach for the social sciences given the rapid development of artificial intelligence tools (e.g., Luan et al. 2020).

Discussions
In this paper, we discussed different potentials, problems, and open questions regarding big data in theories and theory building in the social sciences based on a comprehensive literature review.We found highly heterogeneous assumptions and perspectives resulting in five controversial lines of argumentation.First, on the one hand, the development and use of complex system theories could be the appropriate reaction to big data; on the other hand, social phenomena may not be validly mapped using complex formal systems.Second, some scholars postulate no implications for theories in social sciences as big data only means more of the same.Still, others see gradual changes in the development and testing of theories based on a combination of data-and theory-driven research processes.Third, some authors point out that bad big data could lead to bad theories.Therefore, big data should undergo an advanced evaluation process that must be based on additional data-related criteria but also on existing theories.Fourth, big data-related theories have to meet extended standards for theory development and testing based on the specific type of theoretical framework.However, such extended standards are associated with problems of incompatibility, softening, progressivity, hybrid approaches, and multiple paradigms and disciplines.Fifth, big data might enable the identification (via data mining) of social phenomena that would not be discovered by human imagination.Yet, a conclusive test to determine whether such big data-related tools and procedures are effective or even more effective than more traditional approaches to theory building is still missing.
Our paper is subject to some limitations.We have collected arguments and counter-arguments without offering sound solutions to controversies.We limited our contribution to identifying and relating arguments.We have not developed a meta-or similar theory or approach that would make any type of data and related theory embeddable.Moreover, we have not captured all the important implications of big data for theory building in social sciences.For example, we did not discuss what the creation of big data in real time means for theory building and testing or how the expansion of theories and the scalability of big data approaches are related.However, our collection of problems and open questions can be seen as a starting point for research programs or projects in the social sciences.In this respect, our review not only presents a summary of lines of argumentation but also stimulates future research in the philosophy of social sciences as well as in many other fields of social sciences.
Despite the open questions and limitations, one thing seems to be clear for future social sciences research using big data: the integration of big data into processes of theory development and testing in the social sciences arguably requires an expansion of researchers' skills in the areas of formal logic, mathematics, and computer programming (e.g., Brooker 2020).On the one hand, this implies the need for greater integration of these fields into study programs to be able to train and prepare young social scientists.Additional courses will have to be offered or existing method training will have to be adapted.For example, the software package R could be used not only for statistical analyses in the social sciences but also as a programming tool for complex modeling (e.g., Kennedy and Waggoner 2021).On the other hand, this also makes it necessary for social scientists to expand interdisciplinary cooperation with philosophers of science, logicians, mathematicians, and computer scientists.Social scientists will have to understand how computer programs (analyzing big data) think and that results are not only data but also patterns of abductive inference that require not less but more theoretical work (Schurz 2017).

Conclusions
The role of big data in the social sciences is dominated by a focus on quantitative research methods.However, in this paper, we have reflected on big data and previously underestimated topics related to theories and theory development.We found that the relationship between big data and theories is controversial and changing, requiring continued attention, holistic analysis, and critical appraisal.Dealing with big data will likely generate more complex theories, which will create a number of problems in theory development and associated standards.These problems range from standard incompatibility, standard softening, progressiveness, and hybrid theories to the integration of multiple paradigms or disciplines.We also pointed out that artificial intelligence applications are potentially important tools for theory development using big data.The matter is dynamic, but the philosophy of social sciences should keep an eye on these developments while making more efforts toward interdisciplinarity.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figure 2 .
Figure 2. Big data-related problems in theory building.