|This child is being steretyped before school even begins.|
A remarkable number of people in the world today can readily tell you what house they would belong to at Hogwarts School of Wizardry and Witchcraft. One of the core organizing principles of Harry Potter's alma mater is the 'sorting' of students into four houses, generally distinguished by the characteristics the students in each are supposed to exemplify.*
Identifying oneself as a Ravenclaw or Hufflepuff may be highly amusing for an adult who wishes to knit a Quidditch scarf, but it's one of the worst pedagogical ideas I've ever heard. In the highly unlikely event that I am ever tapped to fill the shoes of such luminaries as Phyllida Spore, Newton Scamander and Albus Dumbledore--should I ever, in short, become Headmistress of Hogwarts School of Wizardry and Witchcraft, I plan to dismantle the entire system.** The Sorting Hat will be going to a museum. Students will be assigned to their house by a random system modified to avoid any child attending the house his parents were in.
First off, there is this business of entrusting the placement of these ickle Firsties to the Sorting Hat. Exactly what the Sorting Hat's degree of sentience is isn't clear. It was supposedly enchanted by Godric Gryffindor, the founder of Gryffindor House, and may be the rough magical equivalent of the sorting quizzes now found online, where a handful of leading questions about your personality and preferences will place you in one group or another. Worse, I suspect from its conversation with Harry that it is essentially placing children where they think they belong, in the house their parents were in, or the one that appeals to them most.
However, even if the hat is gifted with more insight than I give it credit for, as an educator, I find the system problematic the extreme. The houses live together, eat together, play only with one another on sports teams, and attend classes in groups. They are able to speak to people in other houses, and make friends across house lines, but their grouping controls a great deal of who they will spend time with during their formative years at Hogwarts. And they're being put with people who are just like them.
Think about this. There is no roommate from whom a Ravenclaw can learn that a B on a test does not mean the world is ending. There is no one to suggest to a Hufflepuff that a leadership position might suit them after all. There's certainly no one to say 'perhaps you're going to develop into a different sort of person than you thought'. Everyone has been typecast at the door by the Sorting Hat, and they're going to STAY typecast, because at Hogwarts, who you are in the sixth grade is who you're going to be for the rest of your life.
The problem with the house system at Hogwarts becomes clearest, though, looking at the situation in Slytherin. Slytherin's defining characteristic is supposedly ambition ("by that sin fell the angels", ya know), but students from all the houses demonstrate ambition, and aiming high is considered a fairly ordinary thing at a school which educates the elite of the wizarding world. I'd add, as well, that the Slytherins we see generally don't appear to be particularly cunning or 'ambitious'. Mostly, with the exception of the unfortunate Draco Malfoy, who does his best to imitate his father's style, they seem be dimwitted bullies, or sullen spiteful types. They may be suck-ups, but they're not very charming suck-ups.
I don't know how Salazar Slytherin's early plan of teaching only ambitious pure-bloods used to work out, but by the time of the Harry Potter books, the house has become a dumping ground for children already at risk of going rotten. They are evidently mostly students who are from homes where their parents also went through Hogwarts in Slytherin, and they are disproportionately the children of Death Eaters, and those who sympathize with them. They are also likely to be from families preoccupied with the purity of their wizarding blood, and bigoted against mixed-blood and Muggle-born wizards and witches.
Socially speaking, taking all of these children and concentrating them in a single house together is a recipe for disaster. Students at Hogwarts are encouraged to take their identity from their house, and show loyalty to it. This is problematic in the other houses, for all the reasons identified above, but in Slytherin it it is simply tragic. Rather than seeing that there is a broader world, in which blood is unimportant, and Voldemort, far from being a hero, is a murderer of other people's parents, in which people cooperate as well as compete, the Slytherins are put in a setting where everything they have been taught at home is reinforced.
It's not surprising that 'there isn't a witch or wizard that went bad that wasn't in Slytherin', and a fair amount of the blame for that needs to go to Hogwarts' ridiculous system of sorting into houses. Given how long this has been going on for, the reign of the Sorting Hat could, in fact, be considered a significant factor in the rise of Voldemort and the continued loyalty of the Death Eaters over a generation.
It is an AWFUL idea, and in the final pages of the series, you see the process beginning all over again. Oh, sure, Harry assures his son that Slytherin isn't so bad as all that, invoking poor old Snape's name (Snape, another victim of Slytherin BTW), but you know the damn sorting hat is going to read little Albie's deepest wishes and yell "GRYFFINDOR", while little Scorpius goes to Slytherin, and it will all start all over again.
*For those of you who live under rocks, I shall quickly sum up: Gryffindor, associated with courage and 'best foot forward' heroics, house attended by Harry and his closest friends; Ravenclaw, associated with brainyness and intellectual focus; Slytherin, officially associated with 'cunning' and 'ambition', and unofficially with magical facism; and Hufflepuff...God knows. OK, Hufflepuffs are supposed to be diligent, fair and loyal, but despite her best efforts, Rowling manages to make this sound like something of a curse. The Hufflepuffs are described in one poem about the houses as 'all the rest', which pretty much says it all.
**Those of you who are appalled by this should not worry too much. I've applied for the Defense Against The Dark Arts position for three years running and have never gotten so much as a 'we will keep your resume for future reference' e-mail back.***
***Since Defense Against The Dark Arts appears to be offered in every year, why is there only one teacher covering it in any given year at Hogwarts? Prepping seven classes is cruel and inhuman. I'm not sure they'd keep anyone longer than a year even if circumstances didn't keep intervening.