Quote from Naaga on March 11, 2023, 11:33 am

I have often wondered about it and saw my inner theory validated by this meta which I'm gonna share with you guys.

Source : The best way to tackle Dementors by newfriend999

In 'Half-Blood Prince', Severus Snape finally fulfills his ambition to teach Defence Against the Dark Arts at Hogwarts. In all the previous stories Professor Snape is cast in opposition to the incumbent: Quirrell, Lockhart, Lupin, "Moody" and Umbridge. By the end of each book, Snape's objections are shown to have a cause beyond simple jealousy. All the DADA teachers have a secret that threatens the wellbeing of the students.

Yet in 'HBP' Snape does find a former DADA teacher to clash with: Harry Potter. Harry is the reason many of the students are able to continue DADA to NEWT Level. He schooled them in DADA as leader of Dumbledore's Army during the events of 'Order of the Phoenix'. While Snape-versus-Harry is a constant at Hogwarts, they now have one professional conflict: the best way to repel Dementors.

"Harry fully expected to receive low marks on his [test], because he had disagreed with Snape on the best way to tackle Dementors."

– 'Half-Blood Prince'

In fact, Remus Lupin talks about "certain defences" (plural) when Harry wants to ward off Dementors in 'Prisoner of Azkaban'. Nine out of ten Gryffindors who expressed a preference say they handle the demonic pests with a Patronus. And Harry is phenomenal at casting the Patronus charm. But Snape, we infer, demolishes Harry's case.

Snape's unspoken reasons for shooting down the Patronus option would be intensely personal:

• happiness: the Patronus charm requires a memory of extreme happiness, which would push the buttoned-up Snape to think private thoughts of Lily Evans in the classroom
• fathers: Snape hates his own father and hates Harry's father (in Latin, the word Patronus = father)
• the big secret: Snape's Patronus takes the form of a doe, the same as Harry's mother's*. The doe reveals Snape's secret love

Frustratingly we never hear what Snape proposes as an alternative. But there are clues. Sirius Black does not succumb to the Dementors in prison because he knows he is innocent, and later because of a joyful fixation on escape and murder. In Book Seven, Harry's ghostly parents keep the Dementors at bay. And then, when carried back to the castle, Harry's own recent death-sacrifice safeguards his soul. Sirius is also not detected by the Dementors when in dog form.

None of which are very practical. Becoming an Animagus is time-consuming and unachievable for the entire sixth year DADA class. Vengeance and resurrection seem equally out of reach. But Snape's disagreement with Harry recalls the disastrous Occlumency lessons in 'OotP'. Which may suggest a solution.

"Dementors can't see [...] They feel their way towards people by sensing their emotions."

– 'Prisoner of Azkaban'

Snape knows something about controlling emotions. He is an outstanding Occlumens. And an Occlumency-based approach is the most likely alternative to Expecto Patronum: suppress the emotions and the Dementors jog on. It's subtle, it's sly, it's not as showy as the Patronus. Snape plays to his strengths. Slytherin are, as the Sorting Hat says, "cunning folk". Dementors cannot suck your soul if they cannot feel your presence.

The professor's Occlumency-rooted fix for Dementors also illuminates the DADA clash with Harry. Of course the Chosen One would argue against Occlumency! Harry remains a dope at this point when it comes to closing his mind. But Snape may still want to encourage Harry in this skillset, guilty at his failure to teach him the previous year and very aware that the boy is the only hope for them all.

*Being a female deer, the doe might be considered a Matronus. Feminine, maternal. Even when conjured by Snape, the silver doe carries the idea of Lily Evans/Potter, Harry's mother.