Ontology in research is the study of what exists and what is real. It’s the set of assumptions a researcher holds about the nature of reality itself, and those assumptions quietly shape every decision that follows: what questions get asked, what counts as evidence, and which methods are used to collect it. If epistemology asks “how can we know things?”, ontology asks the prior question, “what is there to know about in the first place?”
Why Ontology Matters in Research
Every research project rests on beliefs about reality, whether the researcher states them or not. A physicist measuring the speed of a particle assumes that particle exists independently of anyone observing it. A sociologist studying how communities define “wellbeing” assumes that wellbeing is not a fixed thing but something people construct through their experiences and interactions. These are ontological positions, and they lead to entirely different studies.
The practical consequence is significant. Two researchers studying the same broad topic, say individual wellbeing, can reach conclusions with very different validity depending on their starting assumptions. Humanistic psychologists treat the “individual” as a product of self-awareness and social interaction. Positive psychologists treat the individual as something that exists alongside the formation of any human being. Those different ontological starting points send each study down a separate path and produce findings that cannot be directly compared. Making your ontological stance explicit is part of what methodologists call transparency, and it is one of the core criteria for rigorous, trustworthy research.
The Main Ontological Positions
Realism
A realist ontology assumes that reality is objective, external, and independent of human perception. There is one tangible reality out there, and it can be observed, measured, and understood through empirical evidence. This is the default assumption behind most natural science. Gravity works the same way whether or not anyone is thinking about it. When a researcher adopts this position, the goal is to discover facts about that single, stable reality using controlled experiments, measurements, and statistical analysis.
Relativism
A relativist ontology takes the opposite view: reality is not fixed. Instead, it is shaped by individual and collective experiences, influenced by social, cultural, and historical contexts. Under this lens, reality is fluid and negotiated, and knowledge is constructed through interactions between the researcher and the people being studied. There are two common flavors. Individual relativism holds that each person constructs their own reality through personal experience. Social relativism holds that reality is constructed collectively through cultural norms and shared interaction. Qualitative research in fields like anthropology, education, and sociology often operates from a relativist stance because the phenomena being studied, things like identity, meaning, and social norms, do not exist independently of the people experiencing them.
Critical Realism
Critical realism sits between pure realism and relativism. It accepts that an objective reality exists independently of human perception, but argues that this reality is not entirely accessible through direct observation. Instead, reality is layered. Critical realists describe three levels: the empirical level (what people directly experience and perceive), the actual level (objects and events that occur in the real world regardless of whether anyone observes them), and the “real” level (deeper structures and causal mechanisms that generate those events but remain hidden). A critical realist studying poverty, for example, would look beyond the observable facts of income and housing to ask what underlying economic or political structures produce those conditions. This framework is popular in social science because it goes beyond rich description to actively seek explanations, drawing on different social theories to account for the complexity of everyday life.
How Ontology Connects to the Rest of Your Research
Ontology is the foundation of what researchers call a research paradigm, the overarching framework that guides a study. It works in a chain. Your ontological position (what you believe is real) determines your epistemology (how you think knowledge about that reality can be gained), which in turn determines your methodology (the specific tools and techniques you use).
A realist ontology pairs naturally with a positivist epistemology and quantitative methods. If you believe there is one measurable reality, you design experiments, collect numerical data, and test hypotheses. A relativist ontology pairs with a constructivist or interpretivist epistemology and qualitative methods. If you believe reality is constructed through human experience, you conduct interviews, observe behavior in natural settings, and analyze language and meaning. Critical realism supports mixed methods, because its layered view of reality calls for both observable data and interpretive analysis of hidden mechanisms.
This chain matters because misalignment creates problems. If you claim a relativist ontology but then use a tightly controlled experiment with a predetermined hypothesis, your methodology contradicts your stated beliefs about the nature of reality. Reviewers, supervisors, and examiners look for this kind of internal consistency.
Ontology in Quantitative vs. Qualitative Research
In quantitative research, the ontological assumption is typically realist. The researcher treats the variables being measured as things that exist in a stable, observable form. Blood pressure, test scores, chemical concentrations: these are treated as objective facts. The researcher’s job is to measure them as accurately as possible while minimizing personal bias. The relationship between researcher and subject is detached by design.
Qualitative research generally operates from a constructivist or relativist ontology. The researcher acknowledges that meaning is created through interaction, and that language itself plays a central role in shaping human experience. This is why qualitative studies often focus on interviews, narratives, and observation rather than numerical measurement. The goal is not to discover a single truth but to understand the multiple, sometimes competing realities that people inhabit. One ongoing tension in qualitative work is balancing the recognition that human experience is deeply individual with the practical need to identify themes and patterns across participants. Prioritizing what is common or general can sometimes flatten the very individuality the ontology is meant to honor.
Stating Your Ontological Position
In a thesis, dissertation, or research proposal, you will typically be expected to state your ontological position early in your methodology chapter. This is not a formality. It signals to your reader that you understand why you chose your methods and that your entire study hangs together logically. The statement does not need to be long, but it should be clear. Name your position (realist, relativist, critical realist), explain briefly what it means, and then show how it connects to the epistemology and methods you have chosen.
Transparency at this stage has a direct effect on how your findings are judged. Every step of the research process, from how you formed your theory and designed your study, to how you sampled, collected data, and drew conclusions, can be evaluated for rigor only when the underlying assumptions are visible. When two studies on the same topic reach different conclusions, the explanation often lies not in sloppy methods but in different ontological starting points. Making yours explicit helps readers understand what your findings mean and, just as importantly, what they do not mean.