Can I just say first that I /love/ reading everything you post. I've been a silent follower for awhile, but I'm always so amazed to see your meta! Anyways, I just wanted to ask (and I don't know if you've answered it before), what's your personal theory on why Tywin decided to raise Tyrion rather than desert him? Assuming he's hated Tyrion since he was born, I really do wonder what drove /Tywin Lannister/ to keep the baby?
It’s because Tyrion is a Lannister. The text says as much:
Had I been born a peasant, they might have left me out to die, or sold me to some slaver’s grotesquerie. Alas, I was born a Lannister of Casterly Rock, and the grotesqueries are all the poorer.
Tywin literally believes a Lannister is “worth more” than other people. Even a Lannister with dwarfism is ~better~ than other “lesser beasts”. That was one of the things the show did right in season 1, when Tywin explains how Tyrion “may be the least of the Lannisters, but he’s still a Lannister.”
Tywin doesn’t care about many Lannisters on a personal level (he treats a lot of his own relations like shit tbh), but he cares about Lannisters as … commodities … as parts of the whole. It’s why he sends search parties looking for Gerion after he’s lost, it’s why he sends people searching for Tyrek in ASOS. They’re Lannisters, and Tywin, as the head of House Lannister, looks after his own.
Kevan: “You are my brother’s son.”
Tyrion: “You might remind him of that.”
Kevan: “Do you think he would allow you to take the black if you were not his own blood, and Joanna’s?”
“This escape is folly. You are not to be killed, if that is what you fear. It’s still my intent to send you to the Wall, but I could not do it without Lord Tyrell’s consent.”
Lannisters get special treatment from Tywin that would not be afforded to non-Lannisters. It’s very similar to Walder Frey’s views, actually:
Lord Walder […] was querulous and stubborn, with an iron will and a wasp’s tongue, but he did believe in taking care of his own. All of his own, even the ones who had displeased and disappointed him. Even the ones whose names he can’t remember. Once he was gone, though …
When Ser Stevron had been heir, that was one thing. The old man had been grooming Stevron for sixty years, and had pounded it into his head that blood was blood. But Stevron had died whilst campaigning with the Young Wolf in the west […] It was like to be every son for himself when the old man died, and every daughter as well.
And you have to realize, everyone thought Tyrion was going to die shortly after he was born anyway. Cersei said to Oberyn as a child: ”Everyone says he’s like to die soon. He shouldn’t even have lived this long.” So Tywin believed the “problem” would take care of itself. He got a wet nurse and he hid Tyrion away deep within Casterly Rock and tried to forget about him. But of course Tyrion would never stop crying as a baby, a constant reminder to Tywin. Of course Tyrion clung tenaciously to life in spite of what Tywin thought.
Show!Tywin restraining himself from throwing his newborn son into the sea is not book!canon. As much as Tywin is revolted by Tyrion, as much as he hates him, you don’t just throw Lannisters out. Tyrion’s a Lannister.