If any sufficiently advanced technology is indistinguishable from magic, then any sufficiently powerful being may be indistinguishable from a god.
What is a god, anyway? This is a question that has vexed real-world theologians and other scholars, as they grapple with issues like how to translate the Japanese word kami. It’s easier in fiction, where a god is what the author says it is — and if they reveal that a so-called god is “actually” an alien or a powerful mage, then that entity instantly loses its divine status. “Word of God” (a common term for the author’s opinion) settles all questions of godhood.
Within real-world contexts, though, there are many different ideas about what qualities a god has. And whether we think about them or not, those ideas often seep into our fiction.
As a starting point, let’s take the spectrum from immanence to transcendence. Immanence — not to be confused with “imminence,” i.e. state of being about to happen — is the quality of being present in the world, while transcendence is the quality of being separate from the material universe. Because it will be familiar to many of my readers, possibly the easiest way to illustrate this is to say that Christian theology often holds that God the Father is transcendent, while the incarnation of God as Son through Jesus Christ was immanent.
But don’t take that to mean that an immanent divinity is always walking around in a human body. Speculating about the very earliest forms of religion can get tricky, but it seems like there may have been a gradual shift from the concept of something like the sea as a god, to the concept of a god of the sea. The latter imagines an entity — often more or less anthropomorphic — with power over the sea (and maybe other things as well, like Poseidon with his horses), while the former deifies the sea itself. A sea-god can still be fairly immanent, but it’s moved a step away, compared to the idea that the waves themselves are the divine presence.
Fantasy polytheism often trends heavily toward the immanent. Gods in a typical Dungeons and Dragons setting frequently show up in person, eat and drink, have sex with mortals, and even die. All of these mark them as connected to the material world, and have their parallels with the myths of real cultures. By contrast, I think science fiction, when it bothers to concern itself with religion at all, often leans heavily toward transcendence. And it’s possible to hybridize the two, in the real world or in fiction; Hinduism has Brahman, the Universal Principle which transcends the more immanent gods, and Tolkien gave Middle-Earth both the transcendent Eru Ilúvatar and his immanent creations, the Valar.
Then there are the “omni” traits. In monotheistic religions, the divine is often said to be omniscient (all-knowing), omnipresent (everywhere at once), and omnipotent (all-powerful). To this we may perhaps add omnibenevolent — infinitely benevolent — but this raises the age-old theological question of why evil exists if God has all those qualities, which may get its own essay eventually, so for now we’ll avoid that rabbit hole. Polytheistic religions rarely if ever ascribe these qualities to their gods; they may be all-powerful within their own domains, but not over reality as a whole.
This acknowledgment that a god may not be omnipotent starts leading us in the direction of understanding why “divinity” is not a concept with clean boundaries, and how it is that humans like ancestors or emperors can become deified.
I’ve talked before about mana, the Polynesian concept that over time has been repurposed as the “magic juice” a character in a game expends to cast spells. More properly, it’s the numinous quality possessed by people or places of great spiritual import, and it has possible parallels in other regions of the world, such as the Algonquin manitou or the Roman numen. I’m indebted to the historian Bret Devereaux for pointing out that the etymology numen is “that which is produced by nodding.” In a sense, you can think of this as Captain Picard on Star Trek saying “make it so”: someone who possesses sufficient numen (or mana or whatever) can decree “make it so,” and the world changes.
When you look at it from that angle, it becomes a lot easier to understand the notion of a deified, living emperor, or any other incarnate god. It isn’t that people believed their emperors were omniscient or transcendent or any of the other qualities we may instinctively associate with the divine. Rather, as Devereaux points out, they had a smaller degree of the same type of power the gods had. Since the Roman gods were seen as being part of the broader community rather than separate from it, and since the forms of Roman religion included bargaining with those gods (“if you ensure my child is born healthy, I’ll sacrifice a lamb to you”), the way people related to the gods and they way they related to their emperors were very similar (“if you grant our town a certain legal privilege, we’ll build a temple in your honor”). Both were part of the community, but very distant, and capable of changing the world with a nod.
If you believe that all humans, or all life, or all material things, contain some amount of a divine quintessence — a very immanent belief — then there isn’t necessarily a profound difference of kind between us and the gods. A deity can manifest its presence in a person or a thing, as happens in the cases of religious possession (often seen in West African faiths and their New World cousins) or the infusion of a sacred object (a key element in Shinto ritual). Likewise, a human can ascend to become divine, especially after death, and especially if their great deeds in life demonstrated their power; you see this with both some Shinto kami, such as Tenjin, and with deified Greek heroes like Hercules. It also ties in with the general concept of ancestor veneration, which we’ll come back to in a future essay.
Even when a story doesn’t feature a direct encounter with a god, knowing how people conceive of the divine shapes many things around that topic — including their government, as the example of a deified emperor shows. Taking a moment to consider that question, rather than just slapping down a few deity names and charging ahead, can do a lot to make a fictional religion feel more real.