|"Gee, and we had all hoped those crazy kids would make it work."|
(Major Who spoilers from jump.)
Let's leap directly into what I spent some time setting up in my last post: Steven Moffat is not an idiot. More to the point, he is not a man unaware of narrative cliche. When he puts together a plot about how Davros seems to be asking for forgiveness, and the Doctor seems to be willing to grant it, it is not in the hopes of hoodwinking the audience. The fake camaraderie of a villain is at least as old as Shakespeare, and the awareness of this within fiction stretches back decades as well.
In other words, mistaking this for an easily solved mystery is as big a mistake as thinking we're meant to believe Missy and Clara have permanently been exterminated when the credits of "The Magician's Apprentice" roll. Moffat knows you know.
The question, then, is what we get out of a plot in which Davros' betrayal and the Doctor's awareness of same are both are fully telegraphed? It's what the certain result reveals. Remember the question that seemingly overhanging this battle of wills. Davros was kind enough to make it explicit: is compassion wrong? The answer this show will present to that question was never in any more doubt than that Davros would turn out to be faking. So what we see here can't be an attempt to defend compassion. Instead, it's a mapping out of just how totally Davros' lack of compassion defeats him. This isn't about whether compassion should win, it's why compassion will win.
The two critical moments in the script are Missy (who is once again a delight) explaining what Dalek sewers are, and Davros congratulating the Doctor on the return of Gallifrey. Like Phil Sandifer, there is no doubt in my mind that in that latter moment, Davros was completely sincere. It just stinks of the kind of "protect your own kind" rhetoric that Davros, like most fascists, cloak themselves in. Indeed, it's a fascinating and horrifying glimpse into Davros' mindset. Clearly he sees the Daleks and the Time Lords as being in some twisted sense basically equivalent, opposing forces - the closest to a compliment Davros can give, and all the more disturbing for that. He assumes the Doctor sees the Time Lords the same way he sees the Daleks - the only thing in the universe that counts as "us".
Except of course, as the Dalek graveyard demonstrates, that Davros doesn't even see every Dalek as "us". This leads us directly to the story's statement on why compassion will win: Davros' lunatic obsession with racial purity leads to a philosophical definition of a Dalek rather than a biological one. It simply never occurs to him that the creatures that form the sewers beneath Skaro might be affected by the energy transfer because his ideological blinkers prevent him from seeing them as Daleks.
What this means ultimately is that the Doctor defeats Davros by having a better understanding of the Daleks than their own creator has. His compassion for the discarded and forgotten - even those who before they were tossed aside gloried in mass murder - allows him to thoroughly outmanoeuvre Davros' pathetic assumption that something is only a Dalek if he says it is.
As I've said, the question under discussion not whether "compassion is wrong", as Davros puts it - that's the maximalist position against which the Doctor's response must be measured. The question is whether compassion is in any meaningful sense a weakness. The episode's position on that is a formulation that simply cannot be said enough times. All too often, in fiction and reality, we're told compassion is a weakness, nice in theory, but prone to make one naive and overly trusting, someone to be exploited by others who lack your decency. It's in statements like Nick Clegg's insistence (a pale rewriting of the horrendous Churchill, of course) that the Lib Dems were like the Tories with a heart and Labour with a brain, as though intelligence and compassion were somehow different ends of a scale. It's in the lunatic frothing of every "I'm not a racist but..." racist who insists they don't have any problem with foreigners per se, but that immigrants need to be stopped before they can take advantage of the generous nature of the British people (as though the defining feature of our theft of a quarter of the globe was that we gave stuff out). Everywhere - just everywhere - we hear that we should be ruled by our minds and not our hearts, as though what is smart forever exists in conflict with what is kind.
"The Witch's Familiar" rejects this idea, utterly and gloriously. The Doctor doesn't win out because he's smart enough to overcome the weakness of his compassion, he wins out because his compassion makes him smarter. He beats the fascist by out-thinking him, and his ability to consider the values and desires of those other than himself is what lets him do it. Plurality will beat fascism. Empathy will beat fascism. Compassion is the oil we need to make our brains run more smoothly. Ultimately, the fascists can never out-think those with empathy, because the intellectual furniture of a fascist is by far the easier to pick apart. We can experience and learn from what fascists can only deny.
And whilst the Doctor was clearly playing along with Davros throughout the episode, it doesn't follow that his compassion for a dying old man was completely faked. Indeed, it can't have been, otherwise you get into all sorts of ugly implications about why Davros deserves to be denied simple decency and Missy doesn't . As with Davros' congratulations on the return of Gallifrey, I have no doubt the Doctor was being honest when he explained why he came. This wasn't about some kind of four-dimensional chess move whereby the Doctor could blow up a Dalek city he didn't even know existed. This was about doing what the Doctor thought was right. Showing compassion. You can't go in with your eyes wide open unless you go in.
Doing that is different from forgiveness. I personally don't think I could possibly be bothered that a mass murdering tyrannical pseudo-Nazi had to see his last sunrise on his iEye, but that is my failing. It feels too much to me like forgiveness, which I don't think is actually correct. How one actually differentiates between the two is a question for some other time, though. What matters here is that compassion can be - needs to be - extended even to the worst of us. At the end of the day, contrary to Davros' joke, our hero is a good Doctor. He's a man who knows every person is entitled to a basic level of care, no matter what they have done, and acts - or tries to, on his best days - accordingly.
This, in the end, was absolutely one of his best days.
(Update: This has no connection to anything else here, really, but it just struck me: Colony Sarff is just "Colony South" said with a stereotypical Cockney accent. A mass of snakes, priding itself on being democratic - and thus representative - whilst actually totally under the control of reactionary overlords? That'll be London, then.)
 Actually, I don't think the episode really avoided this. The best we could say here is that there's surely a big difference between meeting someone who is a mass murderer and being friends with someone who later becomes a mass murderer, but with that completely unexamined by the script the final impression is rather too close to suggesting Chaotic Evil characters are less deserving of our hate than Lawful Evil characters simply because the latter are so much more fun to watch.