Ontology, epistemology, and paradigms - What are they, and how much should you write about them in your PhD thesis?

If you’re a PhD student, you’ve probably come across the terms ontology, epistemology, and paradigm more than a few times. And let’s be honest—they sound a bit like academic jargon from another planet. You can almost imagine your supervisors sitting in on a secret meeting where they were given the cheat sheet… and you’re still waiting for yours.

But don’t worry! By the end of this blog, you’ll not only have a clearer understanding of what these words mean, but you’ll also know exactly how and where to write about them in your thesis—in a way that’s clear, concise, and totally doable.

If we’ve not met before—hi! I’m Dr Elizabeth Yardley, and I’ve made it my mission to help PhD students get out of their own way and finish their doctorates without the overwhelm. If you’ve ever found yourself staring blankly at the words ontology, epistemology, or paradigm thinking, “I just don’t GET it”, you’re in the right place. You will soon—promise! Let’s get stuck in.

A quick recap: ontology, epistemology, and paradigms

(And why should you care?!)

Right. Before we get into where and how much you should write about these terms in your thesis, let’s take a moment to demystify them. If you want a more in-depth dive into each of these, I’ve got other blogs and resources you can check out here—but for now, here’s the crash course.

👉 Ontology is the what. What are you looking at when you study the social world? Do you believe there’s one fixed reality out there we can measure—like poverty rates and income levels? Or do you think reality is based on personal experiences and perspectives, like people’s feelings of inequality? Your ontological stance shapes what you believe is real and worth studying.

👉 Epistemology is the how. How should you go about studying and making sense of the world? Should you stand back and observe from a distance, collecting cold, hard data like a scientist in a lab? Or should you get up close and personal, immersing yourself in people’s experiences to understand their unique perspectives? Your epistemology guides how you think knowledge is created and understood.

👉 Paradigm is the big picture. It’s your overall research worldview—the lens you use to see everything in your research. It combines your ontology (what you believe exists) and your epistemology (how you think we should study it). Your paradigm shapes the kinds of questions you ask, the methods you use to collect data, and how you interpret your findings. The most common paradigms in social science research are positivism, post-positivism, interpretivism, pragmatism, and critical realism.

Got it? Great! (And if you’re still feeling a little unsure, that’s normal—give it a few minutes and you’ll see how it all comes together.)

“Wait a second,” I hear you thinking…

“You’ve said interpretivism is a paradigm and an epistemology—what?!”

And yes, I did say that!

Let’s take a breath because this bit trips up a lot of people, and it’s no wonder. You’ll often see terms like interpretivism or positivism used to describe both an epistemology and a paradigm. Confusing, right?

Here’s what’s going on.

Paradigms are big picture worldviews, and they include ontological and epistemological assumptions. But sometimes we use the same word to describe both the paradigm as a whole and the epistemological approach it’s most closely associated with.

For example:

• Interpretivism as a paradigm is the whole package: it assumes a constructivist ontology (reality is socially constructed) and an interpretivist epistemology (knowledge is subjective and based on understanding meaning from people’s experiences).

• Interpretivism as an epistemology refers specifically to how we know things—that knowledge comes from understanding people’s interpretations of their social world.

So it’s not wrong to see interpretivism in both places. It’s more like a shorthand: we say "interpretivist paradigm" because it wraps up those ontological and epistemological assumptions into one neat little box.

But if you’re breaking things down, you can separate them:

• Ontology: Constructivist

• Epistemology: Interpretivist

• Paradigm: Interpretivism

Hope that clears it up! If you’re still thinking, “Hmm, I’m not sure…”, don’t worry. It can take a little while to get your head around this—but you will.

Where should you write about ontology, epistemology, and paradigms in your PhD thesis?

So, you’ve been told you need to mention these terms in your thesis… but where? Should they pop up in every chapter? Should you sprinkle them through your findings like seasoning? Or is there a specific place where they belong?

Here’s the simple answer: They mostly live in your methodology chapter. That’s their home. But you will want to mention them briefly in other places too—particularly in your introduction and discussion.

Let’s break it down.

1. Introduction (just a light mention)

You don’t need a big, detailed discussion of ontology, epistemology, and paradigms in your introduction. This is the place to set the stage and lay out your research questions, so if you mention them at all, keep it brief.

If your study has a strong philosophical angle (as many qualitative studies do), it can be helpful to let readers know where you’re coming from right at the start.

Here’s an example of how you might do that in just a sentence or two:

“This research adopts an interpretivist paradigm, aligned with a social constructivist ontological stance, arguing that reality is not fixed or objective but socially constructed through human interaction. Epistemologically, it recognises that knowledge is shaped by individuals’ interpretations and lived experiences.”

Short. Sweet. No deep dive—just a signal to your reader that you’re grounded in a clear research perspective.

2. Methodology chapter (where the magic happens)

This is where you really get into it. Your methodology chapter is where you explain your philosophical stance in more depth and show how it connects to your research design and methods.

If your examiners are going to look anywhere for this explanation, it’s here—so this is where you want to be clear and confident.

Here’s what to include:

• Your philosophical stance: Explain your ontological position (what you believe reality is), your epistemological position (how you believe knowledge is created), and your paradigm (your overall research worldview).

• The rationale: Why have you chosen this approach? How does it fit with your research aims, objectives, and questions?

• Implications for your methods: Show how your philosophical stance has influenced your choice of methods—whether that’s qualitative, quantitative, or mixed methods.

And don’t worry—this doesn’t need to turn into a philosophy dissertation! Here’s how you can keep it clear and practical.

Sentence starters you can use in your methodology chapter

For ontology:
“This study adopts a [constructivist/realist/etc.] ontological perspective, arguing that [explain your view of reality].”
Example: “This study adopts a constructivist ontological perspective, arguing that social realities are created through human interaction. Therefore, this research focuses on how individuals experience and interpret social phenomena.”

For epistemology:
“This research takes a [interpretivist / positivist] epistemological approach, which suggests that knowledge is [explain how knowledge is understood].”
Example: “This research takes an interpretivist epistemological approach, recognising that knowledge is subjective and shaped by individuals’ experiences.”

For paradigm:
“This study is situated within the [interpretivist/critical realist/etc.] paradigm, which assumes that [brief explanation].”
Example: “This study is situated within the interpretivist paradigm, which assumes that reality is socially constructed and that meaning is derived from human interactions.”

Linking it all to your methods:
“Given the [ontology], [epistemology], and [paradigm] adopted in this study, a qualitative methodology was chosen to explore [research focus].”
Example: “Given the constructivist ontology, interpretivist epistemology, and interpretivist paradigm, this research adopts a qualitative methodology to explore how individuals perceive and make sense of their social worlds.”

3. Discussion or analysis chapter (bringing it back around)

By the time you get to your discussion or analysis chapter, you shouldn’t need to re-explain your ontology, epistemology, and paradigm. But it’s helpful to show how these have influenced your analysis and interpretation of the data.

For example:
“The interpretivist epistemological approach adopted in this study shaped the analysis by focusing on participants’ lived experiences and the meanings they attributed to them, rather than seeking objective truths.”

Or:
“Given the critical realist paradigm, the study highlights how deeper social structures influence participants’ experiences, going beyond surface-level interpretations.”

How much should you write about ontology, epistemology, and paradigms in your PhD thesis?

Now for the big question: How much is enough?

This is one of the most common worries I hear from students—“Am I writing too much? Not enough?”

Here’s the thing: You’re not writing a philosophy textbook. Your job is to explain your stance clearly, show how it relates to your research, and then move on.

You’re aiming for clarity, not complexity.

As a rough guide, around 1,000 words in your methodology chapter is usually enough to cover:

• A brief explanation of your ontological and epistemological stance

• Your rationale for choosing them

• How they link to your research questions, methods, and interpretation of data

And if you find yourself going off on a tangent about the history of ontology since Aristotle? Stop. Take a breath. Ask yourself, “How does this help my reader understand my research?” If it doesn’t, leave it out.

Your examiner (and future readers!) will thank you for keeping things clear and focused.

Final thoughts: keep it clear, keep it relevant, keep it you

The terms ontology, epistemology, and paradigm sound intimidating, but they don’t have to be. At the end of the day, it’s about being clear on your position and showing how it shapes your research choices.

You don’t need to be a philosopher—you just need to explain your thinking in a way that makes sense to your reader.

If you want a bit more help with this, I’ve put together an Paradgims Starter Kit, which breaks this all down into simple terms with examples you can actually use. And it’s free! You can grab it here: Paradigms Starter Kit.

And if you’re stuck, don’t stress—drop me a comment and let me know what’s tripping you up. I’ve got you!

Paradigms Starter Kit - Click here to get yours!