Doctor Who is one of those shows that has a complicated relationship with religion. New Who seems to be written by people who are either mostly ignorant of religion or hostile to it (or both). After all, the Doctor is the great modern champion of science and reason. He’s the enemy of ignorant assimilation, and what better manifestation of ignorant assimilation is there than organized (read: Christian) religion? It’s offensive to religious people, sure, but the science vs faith trope is too juicy for most sci-fi to pass up. So it’s no wonder that when Doctor Who does decide to play with religious ideas, things go haywire. For example, take the idea of a soul. Lots of religions and philosophies have different ideas about what a soul is, and yet instead of sticking to just one, Doctor Who just uses the vaguest idea of what it might mean, whenever it’s convenient.
The one thing most people can agree on is that souls are spiritual, or at least incorporeal, parts of a being. The idea of a soul being immortal is at least as old as Socrates, who thought that the psyche was the rational part of the person that lived on after death. Plato believed that the soul had three parts: reason, emotion, and desire. Aristotle believed the soul couldn’t be separated from the body, that all living beings (from plants to humans) possessed a soul, and that the soul could be mortal. Ibn Sina (Avicenna), made a distinction between the body, soul, and spirit. Thomas Aquinas expanded on both Aristotle and Ibn Sina with a Christian twist, among other things arguing that the soul was immortal and could exist separately from a body. Immanuel Kant didn’t think it was necessary for the soul to be incorporeal, or that we could even prove it one way or the other. Instead, this idea of the soul is deeply connected with one’s sense of self. In many ways, today’s common conception of the soul takes the comforting bits from the past (an immortal part of you) combined with your sense of self to create a nice idea that feels good, but doesn’t really have a function beyond that. That is, unless you’re religious.
Followers of an Abrahamic religion usually believe that your soul is an immortal, essential, spiritual part of you that is judged by God upon death. Even the most nominal Christian, Muslim, or Jew usually believes that if you’re good, your soul enjoys paradise in Heaven. Buddhism, on the other hand, claims that souls don’t really exist in the way Abrahamic peoples conceive of them. Most Buddhists believe that while part of you is spiritual and immortal, that part is in a constant state of flux. That spiritual component is reborn again after bodily death. Hinduism really doesn’t have a concept of a soul, but it does have a sense of self, separate from most of the Western ideas attached to souls (one’s reason, ego, desires, etc.). Taoism professes dualism, that everyone has two kinds of souls within them, hun and po, respectively corresponding with yang and yin. Souls, spirits, and soul-like ideas play important roles in humanity’s religious understanding of itself.
Doctor Who draws from a culturally Christian heritage, but has a rather hodgepodge canon understanding of what a soul might be. The only thing we can really say across the board is that a soul has something to do with what makes a being a particular being and not some other being. That’s pretty nebulous, right? Maybe it has to do with the being’s memories. Doctor Who clearly thinks that what separates a being from another being is its memories, and in its episodes, focuses solely on memories as the basis of a soul.
In The Rings of Akhaten, we meet Merry, who believes that she has to let the sun monster eat her soul so that it won’t eat everyone else’s souls. The Eleventh Doctor claims that souls are made of stories, and so in order to defeat the big scary sun monster, they have to offer it so many memories that it gorges itself to death. The Doctor convinces Merry that she shouldn’t sacrifice herself by using an “alternate creation myth” that romanticizes the Big Bang, and makes Merry feel special because she’s a unique physical creation. It’s lovely, but makes the soul an idea based entirely in one’s physicality. After all, your memories are stored in the synapses of your brain.
We also see the equation of soul with memories in The Doctor’s Wife. Here, the “soul” of the TARDIS is drained from the console and implanted into Idris (after she has her own soul removed). For the first time, we really see what’s been hinted at for ages: the TARDIS really does have its own personality, and is a real being in its own right. In Idris’s body, the TARDIS finally has the ability to communicate clearly with the Doctor. When the body of Idris dies, the soul of the TARDIS is released and able to reunite with its original console. This time we don’t have the same connection with matter, but we do with consciousness. The TARDIS’s soul seems to be formed by some kind of energy. Energy isn’t spiritual, at least not in this case. It’s measurable, and we witness it physically move from one place to another. What makes the TARDIS really itself seems to be the fact that it remembers its past experiences and has a sense of self in relation to those experiences. Again, we have a strong connection between soul and rationality, reason, desire, and even emotion.
However, the problem remains that Doctor Who’s conception of a soul is entirely corporeal, while nearly every other notable definition of a soul is spiritual. A soul belongs to a reality that humans don’t fully understand. The existence of the soul is intrinsically tied to the idea of the nature of life after death, in one form or another. Doctor Who might be using the word “soul” because it doesn’t have a better, more precise term. But in doing so, it does the world a disservice. Connecting the concept of a “soul” with something that is exclusively material makes the word begin to mean the opposite of what it has across multiple cultures and ages. It helps build an atheistic world. And in such a world, it’s even easier to ridicule religious belief as anti-science, anti-intelligence, and anti-reason. Our sci-fi world building doesn’t have to be inherently theistic to be great. But by leaving room for God and spirituality, it also leaves more room for the unknown, and a sci-fi world with the unknown is much more interesting.