What's the Difference Between Ontology and Epistemology?

If you’re writing a dissertation or thesis, you’ve probably encountered these terms. Ontology and epistemology sound intimidating, but they’re actually just two sides of the same coin. Let’s break them down in plain language so you can understand what they mean and how to apply them to your own research.

What Is ontology?

Think of ontology as the study of reality itself. It asks the fundamental question: what actually exists? When you’re doing research, ontology is about deciding what counts as real and what doesn’t. Is something a concrete fact, or is it just a perception, an idea, or something that a community has agreed upon?

Ontology is a big, philosophical question, and that’s exactly why it can feel a bit abstract. But here’s the thing: every researcher has an ontological position, whether they’ve thought about it explicitly or not. Your ontological stance shapes what you’re willing to study and what you believe counts as valid phenomena worth investigating.

What Is epistemology?

Epistemology is about knowledge itself. It answers questions like: what is knowledge? How do we know if something is true? What kinds of evidence count as good evidence? How can we ever be certain about anything?

In your dissertation, you’re creating new knowledge. That’s the whole point. So having a clear epistemological framework upfront is crucial because you need to be able to explain what knowledge is and how you’re going to create it. Your epistemology essentially describes your approach to building knowledge in your field.

How to identify your position

The best place to start is by reading about different types of knowledge within epistemology. If you don’t have a textbook on hand, we often recommend the Oxford Handbook on Epistemology as a solid starting point. Once you’ve refreshed your understanding of the different epistemological approaches, think about which one resonates most with your research question and your goals.

What type of knowledge are you trying to create?

Are you interested in practical, applied knowledge or theoretical knowledge?

Knowledge based on lived experience?

Let these questions guide you toward the epistemological framework that fits your work.

For example, if you’re an educator researching teaching practices, you might draw on practitioner knowledge. This is knowledge that educators have gained through actually doing their work, day in and day out. Our private coaching clients often work with this type of knowledge in their research, combining what practitioners know from experience with other research methods to build a more complete picture. The key is matching your epistemology to your research question and what you’re actually trying to accomplish.

Why both concepts matter

You might be wondering why you need to think about both of these concepts. Here’s why: ontology shapes what you believe exists and is worth studying (your reality), while epistemology shapes how you’ll go about studying it and what counts as proof (your knowledge). In other words, they work together.

Your ontological position determines what phenomena you’re interested in, and your epistemological position determines how you’ll investigate those phenomena. They’re two sides of the same philosophical coin, and getting clear on both helps you build a stronger, more coherent research design.

Learn from existing research

If you’re still feeling stuck after reading some theory, do yourself a favor and look at dissertations and theses that have already been completed in your field. Find ones that have an ontology or epistemology section and read how other researchers have framed these concepts. Your field likely has conventions and preferred approaches, and seeing how others have tackled this problem can give you concrete examples to work from.

You don’t need to reinvent the wheel. Instead, learn from what’s already been done in your discipline and adapt it to your own research context.