Why is a talking cartoon horse making me cry? It’s a question many of us might have asked ourselves as the new season of BoJack Horseman – an improbably moving Netflix cartoon about a version of Hollywood populated by talking animals – surfaced over the weekend.

The characters, led by BoJack (voiced by Will Arnett), make terrible decisions about sex and dating, sell themselves short, and generally end up miserable in the funniest possible ways. It’s a show at the forefront of a recent crop of animated TV series for adults that surpass most live-action shows this side of Twin Peaks in terms of sheer emotional ambition.

There’s BoJack, Adult Swim’s critically lauded sci-fi series Rick and Morty, the Duplass brothers’ Animals on HBO, and Archer, a workplace comedy about a spy agency that has gone crazily off the rails. In broad terms, TV is still embracing what critic Jenny Jaffe dubbed the “sadcom” – a show with an ostensibly comic outlook that trades in for pathos - but something special is happening in animation. With animated shows TV is able to flex different muscles.

BoJack, for example, had a partly wordless episode last season that featured a gorgeous sequence of its titular protagonist, a washed-up actor and horse, chasing a baby seahorse through a cave filled with multicolored, glowing sea anemone. The effect was somewhere between Looney Tunes and Fantasia. Archer has had a dream sequence that has lasted two full seasons and counting. It’s not that you can’t do that sort of thing on live-action television (just look at the Sopranos for ambitious dream sequences), merely that it is so much harder to pull off and takes a lot of money. In cartoon sitcoms, as Archer demonstrates, you can use character as an anchor and change absolutely everything else without breaking the show.

Rick and Morty … Dr Who’s sardonic offspring. Photograph: Adult Swim

Rick and Morty, always gleefully profane, also seems as though it ought to be ill-suited to its stories’ hardcore existentialist leanings. On paper, it sounds like an appealingly high-concept sci-fi series. It follows a bitter mad scientist and his dim grandson on the kind of spacefaring adventures you might see on Doctor Who or Star Trek, but, to give credit where due, in far weirder visual terms, with aliens who are truly alien.

It is, in large measure, a cartoon about disturbingly genitalian interplanetary monsters, xenocidal gaseous intelligences, and plenty more who otherwise look like something HP Lovecraft sneezed. But like BoJack, Rick and Morty is better at plumbing some very deep intra-family emotional depths than nearly anything shot with an actual camera – in a recent episode, Morty’s mother and sister get into a fight and are turned into giant, inside-out Clive Barkerish monsters; only then can they reconcile.

They shows are a new emotional country: fertile, welcoming and as big as anything you can think to draw

Dan Harmon, who co-created the show with Justin Roiland, described it to me this way to me before it premiered in 2013: “If [Justin] says, ‘Well, I want there to be a giant testicle monster with testicles hanging off of it, and it has a vagina in the middle of it,’ what I can provide is, ‘OK, what kind of story might make use of that? Does the testicle monster come in on page one, and what are we learning on page five?’” You, too, can learn valuable emotional lessons from testicle monsters, reader.

Success breeds success on television, so it’s easy to see how these shows stand on the shoulders of giants like South Park, The Simpsons, and Futurama. Without those proofs of concept, Rick and Morty, BoJack Horseman and Archer aren’t possible. For Harmon, BoJack creator Raphael Bob-Waksberg, Archer’s Adam Reed and hopefully many more to come, the colorful and plastic trappings of genre fiction and children’s fantasy – it’s hard to watch BoJack without thinking of Richard Scarry’s children’s books – aren’t incongruous or nonsensical. They’re a new emotional country, fertile, welcoming and as big as anything you can think to draw.

These shows are all formally ambitious in more abstract ways, as well; Harmon and Bob-Waksberg both seem to understand that stasis is built into the nature of the half-hour comedy – you’re breaking the rules if you don’t put things back where you found them at the end of 30 minutes. For decades, this has been a very comforting kind of television to consume. But what Harmon and co understand is that approach speaks to a kind of depressing, existential truth: most imperfect people can’t change. Thankfully for a new generation of animators, they can.