Philosophy is one of those topics where, if you’re intending to explore it in detail in your fiction, you probably already know more about it than I do.

The way we talk about it nowadays, it’s the exemplar of a rarefied field of study, the province of intellectuals who hardly engage at all with the world around them. As a result, you’re unlikely to center philosophy in your worldbuilding unless you know quite a bit about it to begin with (as I, freely confessed, do not). But I do know this much: philosophy is far from disengaged with the world. Indeed, its purpose is to consider why the world works the way it does, how we should engage with it, and other such fundamental and vital questions. So even though my own knowledge is limited, it’s worth taking a bit of time to unpack just what philosophy is.

We’ve touched on parts of it already, because philosophy is not fully separable from other topics. The Year Six essays on sin and salvation? Those got grouped under my broad “religion” header for obvious reasons, but they’re also philosophical topics — specifically the branch known as moral philosophy, which concerns itself with ethical questions like what is good and whether one should weigh intentions or consequences more heavily in evaluating an action. For many people, religion has long been the foundation of moral philosophy . . . though the notion some hold, that a person can’t really be moral without faith to enforce it, is utterly without foundation.

Last week’s science essay also touched on philosophical matters, because philosophy asks questions like “what do we know and how do we know we know it?” This branch is known as epistemology, or the study of knowledge itself. That revolution in thinking I mentioned before, where the Royal Society said nullius in verba and started testing long-held dogma to see if it was right? That was an epistemological shift, one that declared sense experience and experimental procedure to be the proper basis of knowledge, rather than deference to authority.

Science also ties in with the logic branch of philosophy. How do you know if someone’s reasoning is sound? Among specialists, different logical methods often get discussed in very abstract, dry-sounding ways, but we use them all the time in daily life: if you come home to find toilet paper shredded throughout the house and the only living creature who was there is the dog, ergo you conclude the dog is to blame, you’re applying logic. Science, medicine, and the law all share the task of looking at the evidence and attempting to formulate an explanation that adequately explains what you see — or, alternatively, to show that an explanation fails that test. Because, of course, the flip side of logical reasoning is the fallacy: incorrect reasoning, which fails at one or more steps in the chain.

The fourth major branch is metaphysics, and it’s the hardest to pin down (thanks in part to the definition changing over time; that’s what happens when your field of study has been around for thousands of years). This, I suspect, is what most people think of when they hear the word “philosophy,” because metaphysics is the branch asking questions like “why does reality exist?” But here, too, it loops around to touch on other areas of culture, as the beginning and end of the universe fall under this header: religion-themed topics you’ll again find in Year Six.

Enough of the abstractions, though. What does this mean for fiction?

Whether you mean it to or not, philosophy is going to soak your fiction, because it soaks your thinking. If your student at magic school decides to experiment with different ways of casting spells to see if what the teacher said is true or not, that’s demonstrating a certain epistemological stance, one that says experimental results are the most valid way to answer a question. If your protagonist investigates a mystery and comes up with a theory about what’s happening, they’re using a specific logical approach. If your villain is pursuing a potentially admirable outcome by really terrible means, they’re subscribing to a consequentialist view of ethics, the one commonly shorthanded as “the end justifies the means.”

If you don’t make a conscious effort to worldbuild the philosophy of your setting, its philosophy is likely to default to yours. Which is not necessarily a bad thing! But it can feel anachronistic or otherwise out of place. If the protagonist in your medieval-esque story approaches questions of knowledge and logic like a modern scientist, they’re going to feel a bit like a modern person dressed up in fancy clothes. If the good guys all do that while the bad guys adhere to different philosophical stances, now you’re adding an implied moral dimension to the result.

And I suspect that for most stories, it’s that ethical dimension of philosophy where this influence becomes most obvious and, at times, problematic. Protagonist does a bad thing, but it gets brushed off because they’ve got a good heart and that makes it okay? The story is presenting a philosophical argument, whether the author thinks of it that way or not. When the chips are down and a character has to make a hard decision, which way do they jump? Will they bend or break a principle to help someone in need? Will they sacrifice their own desires for the sake of upholding that principle? This is the stuff of deep personal drama, and simply recognizing it as such — and thinking about what stances the various answers would express — can result in more powerful stories, rather than simple ones where the supposed hard choice is really a no-brainer.

But especially on that ethical front, it’s going to be difficult to write a story that endorses a philosophy you, the author, do not support. Deontology, for example, is the field that looks at ethics from the perspective of obedience to rules . . . and for many of us, that rapidly leads to “lawful evil” territory. We’d have a hard time writing a sincere story in which the protagonist virtuously obeys a terrible order because their duty requires it — not as anything other than a tragic ending, anyway. It could be the basis of a villain or an antagonistic society, though, and in fact we often deploy these elements in exactly that fashion.

So even if you don’t have a degree in philosophy, just dabbling your toes in the shallow end of that ocean-sized pool can help you become more aware of what message your worldbuilding and plot are sending. And that, I think, is worth it!