Murray The Magician is pulling a disappearing act on the Academy of Magical Arts -- this after having his fill of what he deems as the org's inconsistent values.

TMZ has obtained Murray's resignation letter -- and he makes it clear the recent investigation into his viral online reveals of magic tricks left him feeling like it was time to make his grand exit.

In the letter, Murray pulls back the curtain on what he sees as the AMA's outdated rules ... pointing out while they've been around since 1962, they're struggling to keep up in the era of social media where magicians are spilling secrets left, right, and center.

He also notes the irony in the org demanding he remove the vids from his personal page or face expulsion. Murray says, "This ultimatum coincides with the Academy's recent honoring of other famous performers with a Performing Fellowship Award. While I admire their work, it's undeniable that their unique style involves revealing key magical principles."

Murray says it's that inconsistent stance on exposing tricks, and his belief in freedom of expression that made him seriously question his place in the AMA, to the point where he feels its values no longer align with his.

Despite all that, Murray claims there's no bad blood, and he's even extending an invitation to anyone from the org to catch his Vegas or tour shows anytime.

You'll recall ... Murray was infamously suspended from AMA-owned Magic Castle, after he shared a video where his wife Dani exposed how he did all his magic tricks.