Don’t get me wrong, fellow Whovians; I love the “The Impossible Planet/The Satan Pit” double episode. It’s got the shippy Ten/Rose stuff that I live and breathe; it’s got genuinely interesting sciencey-wiencey concepts, it’s got foreshadowing to die for, and it’s got an edge-of-your-seat, truly terrifying plot. I’d easily rank this among the scariest episodes of Doctor Who, maybe beaten only by “The Impossible Astronaut/Day of the Moon”.
What about theologically, though? This episode presents a lot of interesting and potentially confusing ideas that I’d like to parse through.
Just to rehash the plot, in this episode Ten and Rose get stranded on Krop Tor, a planet hanging in an impossible orbit around a black hole. According to legend, the name means “The Bitter Pill”, because the black hole won’t swallow it, and the humans staffed there are explorers, drilling down to find a massive energy source residing at the planet’s core.
Weird shit starts happening, and the Doctor and Rose are split up when the Doctor goes into the drilling shaft to investigate what’s down there. He discovers a massive, man-made (or at least sentient-creature-made) structure, and a carved hole going even deeper. After some philosophical dialogue about the nature of religion and skepticism and faith and curiosity, he jumps down, and discovers at the planet’s core the corporeal form of the Devil himself.
He is the truth behind every evil and every devil figure in any religion, the reality that inspired the myth. He has been trapped there since before time began, and if he tries to escape the planet’s orbit will decay and he’ll fall into the black hole. The Doctor, trapped away from Rose and desperate, must decide whether to break the Devil’s bonds and send the planet hurtling into the black hole, essentially condemning himself, Rose, and the station’s crew to death in the event horizon.
Like I said, this episode is chock full of feels, excitement, and drama. But very little of the part with the Devil makes sense.
First, let’s look at the idea that this one being is the inspiration for all devil mythology throughout time and space. That’s actually a cool idea. Off the top of my head, I can’t think of another example of this concept being used in fiction. It opens a lot of interesting theological questions about the potential universality of further religious concepts like the existence of God or gods. But the episode never answers those questions. It says that the Beast was imprisoned on Krop Tor by the Disciples of the Light before time began. What does that even mean? The Doctor himself points out that it doesn’t make any sense; there wasn’t anything ‘before time began’. I feel like a Time Lord would know. Theologically speaking God could exist outside of time and the Time Lords might not know about him, but created beings such as angels—which includes the devil, if we’re speaking Christian-ic-ally—cannot.
And even in the case that there was some spiritual battle between the Devil and the Disciples of the Light outside of the scope of time, it seems impossible to me that that battle was in any way physical. So how, then did a physical Devil get locked up in a physical prison orbiting a physical spatial anomaly? If he’s been locked up since before time began, how did the idea of the devil penetrate cultures across space and time? And most importantly, why didn’t these Disciples of the Light (which I’m guessing is a not-actually-religious codename for angels—“Disciples” implies they’re following someone else) just… chuck the Devil into the black hole? Why go to all the trouble of setting up a wacky planet with an eleventh-hour failsafe to taunt the Devil and give him the change to escape?
The Devil is used in this episode as a shorthand for viewers who are familiar with Judeo-Christian myth; it says “this is the biggest, baddest, most powerful and evil threat we can reference in our culture, and those are the stakes the Doctor is up against”. But his inclusion in a show where the plots are generally so based in skepticism and humanism adds a confusing religious element to the show that even the Doctor can’t quite wrap his mind around.
To be fair, I’m sort of operating here on the assumption that the Doctor and the Time Lords know pretty much everything, which is flawed. One of the highlights of this episode is that the Doctor has to face the doubt that the religiously-skeptic worldview he’s always espoused might not be correct. It says there might be things in this universe that we don’t know and might never know.
Without the Devil, this story would fit in better with the mythology that the rest of the Whoniverse has set up, but without the Devil the stakes and therefore the tension would not be as high. It’s a catch-22 that I don’t know how to fix, and it’s a stain on an otherwise excellent pair of episodes.
Lady Geek Girl and Friends 
I loved these episodes! In hindsight I love that Doctor Who can be so unashamedly intellectually ambiguous. And I think what they were playing with here was the concept of Absurdism. The idea that even an almost-immortal being like the Doctor can’t ever know everything, because he is always subjectively in the universe and never objectively outside of it, made for a wonderful dynamic that shook him up a bit as a character. But you’re so right – the physical prison was a bizarre addition that looked amazing, but logically made no sense. And it was a shame that such a universal concept had so many religious undertones – but, yes, the haunting “devil” concept made it more tense for me too!
I have to say, the second part of this two-episode story was one of the few episodes (as in less than five) that I actually skipped. I really didn’t like the first half and couldn’t imagine the second half somehow redeeming it.