Introduction

In game scholarship, ontology refers to projects that attempt to identify and describe the general or most important elements of games and to explain how these elements relate to each other. Ontologies are constructed to serve a variety of purposes and these purposes determine the scope of the ontology, the elements that are included and excluded, the level of granularity and how the ontology is made available for use.

This entry will give an overview of some of the purposes of game ontology, explain two fundamental issues that game ontology has tackled and summarise some of the methods used in developing ontologies.

Ontology and Definitions

Game ontology is closely related to questions of game definition, but is distinct from these. One might expect a game ontology to presuppose (implicitly or explicitly) some definition of games as a necessary means of determining the range of things whose elements are to be identified. However, game ontologies may avoid explicitly defining the term "game" due to the difficulties attendant upon defining such a heterogeneous class of objects and activities. For example, Brock Rough (2018, p. 26) advocates a descriptivist approach to game ontology that identifies the range of things to be considered videogames as those things that "competent users of the relevant term" take videogames to be. This is also (implicitly) the approach taken by the Game Ontology Project: "Rather than develop definitions to distinguish between games/non-games or among different types of games, we focus on analyzing of [sic] design elements that cut across a wide range of games" (Zagal et al., 2005, p. 2). Aarseth and Calleja (2015) take a different tack, avoiding a definition of games by seeing games as a sub-type of "cybermedia." Specifically, they argue that games are simply cybermedia that are labelled as games by some people. An ontology of cybermedia, by which they mean media that comprise mental activity, a material object, a sign system and a mechanical system, can capture all the things that could possibly be labelled games. This flexibility of definition is possible because ontologies do not assume that all elements identified are shared by all games.

Purposes of Ontologies

Ontology is indispensable to the study of games. While not all game scholars engage in ontological work, they all take into their work a set of beliefs about what the key features of games are. As Aarseth and Möring (2020) note, "every game scholar has an ontological basis for their analysis, even if they don't declare it or reflect on it." These beliefs impact the sort of research scholars do and the kinds of disagreements they have. Every theory, in other words, comes with certain ontological commitments: a (perhaps unstated) set of entities that must exist, and must exist in a certain way, in order for the theory to hold true. (See, for example, the section on Gameplay and Representation.) Gregersen (2016) argues that in a multidisciplinary field such as game studies, it is particularly important for scholars to be clear on what ontological commitments their theories entail as this clarity helps to foster productive debate between disciplines. Without this clarity, it is hard to distinguish disagreements that might be resolved from those based on fundamental ontological differences.

While game ontologies do not in themselves seek to classify games into separate categories or genres, they can identify the "identity conditions" (Bartel, 2018, p. 9) that allow us to see common features of some subset of games and thereby assign similar games to a common category or even argue that two seemingly distinct games are in fact the same game. Early game ontologies in anthropology were explicitly in the service of classification¹, with the ultimate aim of categorising games within cultures or tracing the movement of games across cultures as evidence of cultural contact. For example, E.B. Tylor (1879) developed an argument for pre-Columbian contact between Asiatic and American cultures by attending to similar elements existing in the Indian game of pachisi and the Mexican game of patolli. Tylor's argument depended on listing the common elements in the two games and calculating (approximately) the level of probability of their being invented in two places independently. The debate consequent on Tylor's paper rested on identifying and describing game elements, and categorising them as, for example, "specific and structural" or merely "superficial" (Kroeber, 1931, p. 151). Erasmus (1950) rebuts Tylor by arguing that the elements listed by Tylor are not in fact independent from each other but are rather connected together such that the presence of one logically leads to the presence of another. Such an argument relies on an ontology, though not fully developed, that describes the relationship between game elements.

Game histories have also rested on classifications derived from ontologies identifying the general features of games. For example, Murray's History of Chess (1913) makes the case for the Arabic and Indian versions of chess being the same game through a careful comparison of the elements (rules, number of pieces, type of board etc.) in each game. Game classification continues to be an important motivation for constructing game ontologies today (e.g. Teixeira et al., 2020).

Besides being useful in classifications, ontology is also fundamental to the analysis of games. By identifying the main elements of games and their relationship to each other, game ontologies can produce new research questions. This is a stated aim of the Game Ontology Project, which "provides a framework for exploring, dissecting and understanding the relationships between different game elements" (The Game Ontology Project, n.d.). The Game Ontology Project has been used as a framework to study elements of games such as time (Zagal & Mateas, 2007) and goals (Debus et al., 2020). Game ontologies have also been used to understand how players make sense of game elements such as game mechanics (Kritz et al., 2017).

Lastly, ontologies are used to help game designers. In their work on game design patterns, Björk and Holopainen (2005) construct a game component framework to give designers (and game analysts) a common vocabulary and set of concepts to facilitate dialogue across multidisciplinary development teams and researchers. They also argue that, while game ontologies are descriptive of existing games, they can also be used by designers to identify gaps and under-explored areas in the space of possible game designs. Game ontologies have been constructed to solve specific design problems, for example by providing a common framework to implement interoperability in games, where game elements can be shared across games (Parkkila et al., 2017) or to automatically generate game characters based on information extracted from online texts (Sacco et al., 2017).

Ontology is a branch of metaphysics. As such, game ontologies—descriptions of the main features of games and their relationship to each other—are frequently an aid to discussing more general metaphysical problems, such as the nature of interactivity (Frome, 2009) or the relationship between particulars and universals in games (Debus, 2019). On the other hand, how scholars deal with these metaphysical problems will influence the ontology they end up building. Therefore, ontology is useful in clarifying current ideas on fundamental topics in game studies and also in developing or challenging these ideas.

I will now turn to two of these fundamental ideas about the nature of games that are relevant to ontology: the hybridity of games and the type/token distinction in games.

Gameplay and Representation

Many game scholars have observed the hybrid nature of games, advancing arguments about the different layers that constitute a game. For example, Mäyrä (2008, p. 17) claims every game contains a "core" and a "shell":

While the core, or the gameplay layer [sic] concerns everything a player can do while playing the game, and also game rules that govern these actions, the shell includes all the semiotic richness modifying, containing and adding significance to that basic interaction.

This sort of distinction can be found in game reviews that predate the rise of game studies as an academic discipline, where videogame reviewers would give scores based on features such as gameplay or playability on the one hand and story or plot on the other. Graeme Kirkpatrick (2012) argues that the establishment of this fundamental distinction was a key moment in gaming culture and produced the category of "gamer," defined as a videogame enthusiast who was able to understand and appreciate games in terms of gameplay rather than story or plot.

Others have argued for similar binary distinctions within games, though the terms used differ. Some examples of these dual-layer models are those that differentiate between process and data (Crawford, 1987; taken up by Wardrip-Fruin, 2009); rules and stories (Juul, 2011); plot line and play logic (Dyer-Witheford & De Peuter, 2009); story and algorithm (Wark, 2009); aesthetic qualities and formal structures (Salen & Zimmerman, 2003); fictional world and game system (Klevjer, 2006); audiovisual language and interaction processes (Borries et al., 2010); story and gameplay (Rouse III, 2001); visual appearance and procedural rhetoric (Bogost, 2007); and guise and system (Linderoth, 2002). This fundamental binary structure is an ontological commitment that structures many game analyses, too numerous to cite here, in which one or the other layer is bracketed, or in which these two layers are related to each other, demonstrating some sort of alignment or misalignment. One influential example of such an analysis is game designer Clint Hocking's (2007) discussion of "ludonarrative dissonance" in Bioshock.

The initial scope of an ontology is often informed by the fundamental distinction in the game-as-hybrid approach. For example, the Game Ontology Project documents "things that cause, effect and relate to gameplay in order to help characterize and classify the design space of games" and explicitly brackets "representational details of games" such as settings. However, this proves difficult to sustain. For example, the ontology makes a distinction between gameplay rules and gameworld rules, yet it seems that the only difference here is in how the rule is represented. Attempts have been made to extend the Game Ontology Project by adding aspects of representation to its basic structure (Janssen et al. 2019, cited in Teixeira et al., 2020). The game component framework aspect of Björk and Holopainen's (2005) game design patterns project similarly focuses on the "gameplay" aspect of games. Other ontologies include elements such as setting and presentation that include aspects of the game outside the gameplay system (e.g. Tang & Hanneghan, 2011) and efforts have been made to connect these two layers through ontological categories such as goals (Cardona-Rivera et al., 2020).

Types and Tokens

One stumbling block in game ontologies (and in game definitions) is the uncertainty over what sort of thing a game is. Sometimes, the term is used to describe an object—"I bought a game"—at other times to a particular playthrough—"Last night's game of D&D was fun"—and still others to a set of abstract rules that can be implemented in different material forms by different people at different times in different locations—"in this game, aces are high." This has been understood in terms of C.S. Peirce's (1974) distinction between type and token, where a type is a general category and a token is a concrete instantiation of that category (e.g. Debus, 2019).

Much of the discussion on this issue in the literature collapses the game as object and the game as abstract rule set together and places it in contrast to games as processes. For example, van Vught and Glas (2018) define the game-as-object as a particular material object, but argue that those who make this their analytical target do so in order to gain "intersubjective access to the formal components of the game as object" (p. 210). In other words, the real target of analysis is not the game as realised in a particular material form, but rather the abstract system that determines how the game is played. They contrast this with scholars interested in "the form of [the game's] (partly subjective) actualization" (p. 210). Here, the "object" camp is actually interested in the formal structure of the game rather than any particular material realisation of it in a concrete object (e.g. the boxed game you buy at the shop).

In other research, it is the distinction between the game as material object and the formal system underpinning it that is of interest. For example, Danilovic and de Voogt (2021) distinguish between a game's formal system and its material representation in accounting for the transmission of abstract board games across cultures and through history. While the material used to play abstract board games changes between these different cultures, the formal system underpinning them is "modular," being capable of realisation in a wide range of material forms.

In his PhD dissertation, Debus (2019) brings these distinctions together, arguing that both the game as process and the game as object are particulars, each being derived from the abstract game (the "specific"). The abstract game is on the one hand "materialised" in a concrete object when, for example, someone whittles together a chessboard and pieces, and on the other "instantiated" in a concrete process when they sit down in front of the board and use it to play chess. The game as object and the game as process are both, in this view, concrete manifestations of the immaterial form. These distinctions are important in ontologies because the relevant elements are different sorts of things depending on whether we are considering a game as a material object, a process or an abstract structure. Some ontologies are aimed at abstract concepts shared across many games, such as rules, and others are aimed at game contents that are specific to one game (Parkkila et al., 2017).

Methodology

Game ontologies exist at a number of levels of granularity. Some ontologies seek to describe the chief elements of games in general (Aarseth & Calleja, 2015; Björk & Holopainen, 2005; Debus, 2019; Zagal et al., 2005) while others focus on a particular game element and seek to describe the chief variations of this element and how it relates to other elements (Debus et al., 2020; Sacco et al., 2017; Willumsen & Backe, 2015). Still others limit themselves to a particular type of game, for example board games (Kritz et al., 2017) or serious games (Raies et al., 2014; Tang & Hanneghan, 2011; Teixeira et al., 2020).

Whatever the type of ontology, it is never possible, or even desirable, to describe all possible elements and relationships. Ontologies seek to describe some subset of elements that are deemed to be more important than the rest. Ontologies must therefore have some method for determining what the chief elements are, and filtering out elements that are, by that determination, not so important. For example, Caillois' (2001) famous classification of games into four categories—agôn, alea, mimicry and ilinx—rests on the claim that the player's role in the game is a more important element than, for example, where the game is played or what materials are used to play it. Ontologies, by their nature, make such a claim to the relative importance of different elements of games, but this claim is not absolute. Rather, it is related to the purpose of the ontology. For example, the bracketing of representational issues by some scholars does not entail the claim that such issues are of no importance to game studies writ large. But it does rest on a claim that, for the stated purpose of the ontology—to facilitate discussion and research on gameplay—elements such as character and plot are less important than elements such as rules and goals.

Game ontologies rely on a number of methods to gather, sort and interpret relevant data. Though not all researchers are clear on their methodological approach, data is generally collected by playing a large number of games, observing others playing games, and analysing a range of game-related documents such as reviews, manuals and websites. This is sometimes supplemented by interviews with subject experts (e.g. game developers), often to identify gaps in the data or verify the usefulness of categories (as in Björk & Holopainen, 2005).

This data is then sorted, analysed and interpreted, and again a number of different methods can be used. Competency questions may be used to match the purpose of the ontology to the categories to be constructed (Franco et al., 2018). These are the set of questions that the ontology ought to be able to answer. Specifying competency questions at the beginning of a project allows for the later evaluation of the complete ontology. The competency questions may be derived from interviews or brainstorming sessions with subject experts, e.g. game designers in the case of ontologies intended to aid game development. To determine the relative importance of different elements, the Game Ontology Project adopts prototype theory, reasoning that those elements observed in a large number of games are the most general features of games and those observed in fewer games belong at the more specific level (Zagal et al., 2005). The game design patterns project establishes its component framework initially by building on previous frameworks for a shared vocabulary for game designers, then extends this by attempting to apply it to individual game examples (Björk & Holopainen, 2005).

A number of methodologies have been developed in computer science for the development of ontologies, and these have been employed in several game-related projects. For example, Noy and McGuinness (2001) have developed a guide to creating ontologies, and this is used by Tang and Hanneghan (2011) and Teixeira et al. (2020) to construct their game ontologies. Franco et al. (2018) and Parkkila et al. (2017) both adopt a NeOn Methodology for ontology construction.

Ontologies are made available in different formats. Acknowledging the changing nature of game ontologies, where changes in design or changes in our understanding of games lead to discovery of new elements and relations, the Game Ontology Project is available as an editable wiki (The Game Ontology Project, n.d.). Other ontologies feature in books or journal articles (e.g. Aarseth & Calleja, 2015; Björk & Holopainen, 2005). Still others, usually aimed at facilitating game development, make the ontology available in a computer-readable format to allow computer agents to extract information from the ontology and apply this in an automatic fashion to game development tasks (e.g. Ðuric & Konecki, 2015).

Future work

Game ontology is a moving target. New game genres, platforms, mechanics and business models (see also Monetization) arise frequently, and while some may be incorporated within existing ontologies, others may challenge what players, designers and scholars accept as what a game is. One need only look at the controversies over such genres as walking simulators to see that there is not one game ontology for everyone and for all time. As such, the scholarly work needed in this area continues.

Furthermore, as noted earlier, scholars such as Gregersen (2016) and Aarseth and Calleja (2015) have called for scholars from different disciplines to clarify their own ontological commitments, but this call remains largely unanswered. Most work explicitly focused on ontology takes place amongst scholars working in a formalist tradition. Other areas, for example work on player communities, is still an area for development in mapping out ontologies. Such work would lead in turn to a need for work on how different ontologies do in fact relate to each other. This work has been begun in Aarseth and Grabarczyk (2018) but can only really be developed as genuinely competing ontologies become available.

The development of ontologies in disciplines outside the formal tradition would have the added benefit of opening out the sorts of elements included in this area of research. Brock Rough (2018, p. 24) sees ontology reaching a new stage in game studies, one that involves "consideration of those elements that go beyond an object's intrinsic properties and include candidates like social construction, history, and intentions." Similarly, Willumsen and Backe (2015) gesture in their work toward an ontological method capable of integrating such things as player interpretation. The development of game ontology into these areas brings with it significant challenges, but also will be productive in developing the fundamental concepts in the field.

Aarseth, E., & Calleja, G. (2015). The Word Game: The ontology of an indefinable object. Proceedings of the 10th International Conference on the Foundations of Digital Games (FDG 2015). http://fdg2015.org/papers/fdg2015_paper_51.pdf

Aarseth, E., & Grabarczyk, P. (2018). An Ontological Meta-Model for Game Research. Proceedings of DiGRA 2018. Turin.

Aarseth, E., & Möring, S. (2020). The game itself?: Towards a Hermeneutics of Computer Games. International Conference on the Foundations of Digital Games, 1–8. https://doi.org/10.1145/3402942.3402978

Bartel, C. (2018). Ontology and Transmedial Games. In J. Robson & G. Tavinor (Eds.), The Aesthetics of Videogames (1st ed.). Routledge.

Bell, R. C. (1969). Board and Table Games from Many Civilizations. Revised Edition. Oxford University Press.

Björk, S., & Holopainen, J. (2005). Games and design patterns. In K. S. Tekinbas & E. Zimmerman (Eds.), The game design reader A rules of play anthology. MIT Press.

Bogost, I. (2007). Persuasive games: The expressive power of videogames. MIT Press.

Borries, F. von, Walz, S. P., & Böttger, M. (2010). Space Time Play: Computer Games, Architecture and Urbanism: The Next Level. Birkhäuser Basel.

Caillois, R. (2001). Man, Play, and Games (M. Barash, Trans.). University of Illinois Press.

Cardona-Rivera, R. E., Zagal, J. P., & Debus, M. S. (2020). Narrative Goals in Games: A Novel Nexus of Story and Gameplay. International Conference on the Foundations of Digital Games, 1–4. https://doi.org/10.1145/3402942.3402986

Crawford, C. (1987). Process intensity. Journal of Computer Game Design, 1(5).

Culin, S. (1907). Games of the North American Indians. Dover Publication Inc.

Danilovic, S., & de Voogt, A. (2021). Making Sense of Abstract Board Games: Toward a Cross-Ludic Theory. Games and Culture, 16(5), 499–518. https://doi.org/10.1177/1555412020914722

Debus, M. S. (2019). Unifying Game Ontology: A Faceted Classification of Game Elements [PhD]. IT University of Copenhagen.

Debus, M. S., Zagal, J. P., & Cardona-Rivera, M. S. D., José P. Zagal, Rogelio E. (2020). A Typology of Imperative Game Goals. Game Studies, 20(3). http://gamestudies.org/2003/articles/debus_zagal_cardonarivera

Ðuric, B. O., & Konecki, M. (2015). Specific OWL-based RPG Ontology. 185–190.

Dyer-Witheford, N., & De Peuter, G. (2009). Games of empire: Global capitalism and video games. University of Minnesota Press.

Erasmus, C. J. (1950). Patolli, Pachisi, and the limitation of possibilities. Southwestern Journal of Anthropology, 6(4), 369–387.

Franco, A. O. R., Rolim, T. V., Santos, A. M. M., Silva, J. W. F., M.P. Vidal, V., A.C. Gomes, F., Castro, M. F., & Maia, J. G. R. (2018). An Ontology for Role Playing Game. Proceedings of SBGames 2018, 615–618.

Frome, J. (2009). The Ontology of Interactivity. The Philosophy of Computer Games Conference. Oslo.

Gregersen, A. (2016). Enter the disagreement matrix or "let's talk ontology, game studies." DiGRA/FDG '16 - Abstract Proceedings of the First International Joint Conference of DiGRA and FDG, 1–2.

Hocking, C. (2007). Ludonarrative Dissonance in Bioshock. Click Nothing. https://www.clicknothing.com/click_nothing/2007/10/ludonarrative-d.html

Jünger, F. G. (1959). Die Spiele. List.

Juul, J. (2011). Half-Real: Video Games Between Real Rules and Fictional Worlds. MIT Press.

Kirkpatrick, G. (2012). Constitutive tensions of gaming's field: UK gaming magazines and the formation of gaming culture 1981-1995. Game Studies, 12(1). http://gamestudies.org/1201/articles/kirkpatrick

Klevjer, R. (2006). What is the avatar? Fiction and embodiment in avatar-based singleplayer computer games [PhD]. University of Bergen.

Kritz, J., Mangeli, E., & Xexéo, G. (2017). Building an Ontology of Boardgame Mechanics based on the BoardGameGeek Database and the MDA Framework. Proceedings of SBGames 2017, 10.

Kroeber, A. L. (1931). Historical reconstruction of culture growths and organic evolution. American Anthropologist, 33(2), 149–156.

Linderoth, J. (2002). Making sense of computer games: Learning with new artefacts. International Conference on Toys, Games and Media.

Mäyrä, F. (2008). An Introduction to Game Studies. SAGE.

Murray, H. J. R. (1913). A history of chess. The Clarendon Press.

Noy, N., & McGuinness, D. (2001). Ontology Development 101: A Guide to Creating Your First Ontology. Knowledge Systems Laboratory, 32.

Parkkila, J., Radulovic, F., Garijo, D., Poveda-Villalón, M., Ikonen, J., Porras, J., & Gómez-Pérez, A. (2017). An ontology for videogame interoperability. Multimedia Tools and Applications, 76(4), 4981–5000. https://doi.org/10.1007/s11042-016-3552-6

Peirce, C. S. (1974). Collected papers of Charles Sanders Peirce (C. Hartshorne & P. Weiss, Eds.). Harvard University Press.

Raies, K., Rebhi, K., & Khemeja, M. (2014). Towards Ontology of Gameplay: Application to Game Based Learning Systems. In I. Boughzala, D. Lang, & S. Assar (Eds.), CEUR Workshop Proceedings (Vol. 1288, pp. 26–37).

Rough, B. (2018). Videogames as neither video nor games: A negative ontology. In J. Robson & G. Tavinor (Eds.), The Aesthetics of Videogames (1st ed., pp. 24–41). Routledge.

Rouse III, R. (2001). Game Design: Theory & Practice. Wordware Pub.

Sacco, O., Liapis, A., & Yannakakis, G. N. (2017). Game Character Ontology (GCO) A Vocabulary for Extracting and Describing Game Character Information from Web Content. Proceedings of the 13th International Conference on Semantic Systems, 9–16. https://doi.org/10.1145/3132218.3132233

Salen, K., & Zimmerman, E. (2003). Rules of Play: Game Design Fundamentals. MIT Press.

Tang, S., & Hanneghan, M. (2011). Game Content Model: An Ontology for Documenting Serious Game Design. 2011 Developments in E-Systems Engineering, 431–436. https://doi.org/10.1109/DeSE.2011.68

Teixeira, S., Boas, R. V., Oliveira, F., Araújo, C., & Henriques, P. R. (2020). OntoJogo: An Ontology for Game Classification. 2020 IEEE 8th International Conference on Serious Games and Applications for Health (SeGAH), 1–8. https://doi.org/10.1109/SeGAH49190.2020.9201876

The Game Ontology Project. (n.d.). Game Ontology. Retrieved February 24, 2022, from https://www.gameontology.com/index.php/Main_Page

Tylor, E. B. (1879). On the game of Patolli in ancient Mexico, and its probably Asiatic origin. The Journal of the Anthropological Institute of Great Britain and Ireland, 8, 116–131. https://doi.org/10.2307/2841019

Vught, J. van, & Glas, R. (2018). Considering play: From method to analysis. Transactions of the Digital Games Research Association, 4(2), Article 2. http://todigra.org/index.php/todigra/article/view/94

Wardrip-Fruin, N. (2009). Expressive Processing: Digital Fictions, Computer Games, and Software Studies. MIT Press.

Wark, M. (2009). Gamer Theory. Harvard University Press.

Willumsen, E. C., & Backe, J. (2015). How to Approach Health Packs in the Wild. Meta­ontological Reflections. Philosophy of Computer Games Conference. Berlin.

Zagal, J. P., & Mateas, M. (2007). Temporal Frames: A Unifying Framework for the Analysis of Game Temporality. Situated Play, Proceedings of DiGRA 2007 Conference, 516–523.

Zagal, J. P., Mateas, M., Fernández-Vara, C., Hochhalter, B., & Lichti, N. (2005). Towards an Ontological Language for Game Analysis. Proceedings of DiGRA 2005 Conference: Changing Views–Worlds in Play, 13. http://www.digra.org/wp-content/uploads/digital-library/06276.09313.pdf

Author Information

Paul Martin is an Associate Professor in Digital Media and Communications at the University of Nottingham Ningbo China. He has degrees in psychology and English literature and his PhD was on space and place as a means of expression in digital games. His current research interests are in meaning in games/game semiotics, educational games, and esports in Chinese universities.

Acknowledgements

I would like to thank Bjarke Liboriussen for conversations that have informed this entry. In particular, the list of scholars who have identified games as a binary structure was compiled through discussions for a co-taught graduate seminar on this topic.

Citation Information

Martin, P. (2022). Game Ontology. In Grabarczyk, P. (ed.), Encyclopedia of Ludic Terms (Spring 2022 Edition). URL: https://eolt.org/articles/game-ontology

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