I’m going to spare you the labor of kneeling before a mystic guru for decades, joining secret societies and putting up with their drama, and quite possibly reincarnating a few thousand times in order to learn this nugget of wisdom.
I’m cheating slightly by letting you in on the secret, but I’ve been known to bend the rules before.
The process of attaining proficiency in magic is traumatic and shocking. For some, their brains came out wrong at birth and the psychic censor works horribly. Others take strange drugs. Some experience physical traumas, like being struck by lightning or being hit by speeding vehicles. A few have near-death experiences and come back changed. Others put themselves through exteme mental contortions that for variable periods render the initiate batshit insane.
You can’t think like a normal human being, a descendant of mutated apes, and do superhuman things. So under most circumstances your mind– and by extension your spirit– has to change. A lot.
It’s about plasticity. Spiritual plasticity mirroring the neuroplasticity; as above so below. Every time a magician alters their mental state past the breaking point, it’s like having a stroke. After the shock to the system subsides, the magician has to mend and rewire their consciousness like a person learning to walk after a brain injury. This happens over and over and in numerous ways. New abilities and strangeness are acquired along the road.
It’s also about strength. You need to damage muscles through strain in order to rebuild them stronger. The most basic lesson of athleticism.
That plasticity and strength are not for their own sakes, however.
It’s to prepare us for retaining our memories and personality through the death process. Brain death is almost exactly like having thousands of strokes all at once. Instead of oxygen being cut off from one part of the brain and killing a portion, oxygen is cut off from the entire. This is the most extreme trauma a person can experience without uncommon supernatural intervention.
Most people lose their internal coherence at some point after death. It’s no secret that ghostly spirits do not think or behave quite like living people, and some appear to have lost memories and attributes while whooshing about the eerie void. Yet they retain enough that when called up by various means, they have knowledge that only those particular people could possess. In many instances the contact is with an echo of a person or even a trickster spirit, but in others it appears to be a forgetful and confused version of a discarnate human being. (Though sometimes they’re just faking confusion– but that’s a whole different topic.)
When people transmigrate –and I suspect that is a real phenomenon if it doesn’t necessarily happen to everyone– the process of embedding spirit in flesh is similarly disorienting and traumatic. The result is that hardly anyone is born retaining clear memories of their former lives, of spiritual realms– and one’s personality also changes in various ways.
People who have trained themselves to recover from dramatic changes in consciousness, shock, and systemic injury eventually can break that cycle and retain a clear mind, memory, and a stable personality whether they choose to remain in the spiritual realms or return to corporeal existence.
Magic helps us solve problems in many ways. But many things exist which can solve most of those problems which don’t require such extreme and unusual activities. What makes magic unique is that it gradually (and often very uncomfortably) prepares us for a more advanced existence as a spirit.