As much as power is "measurable", awareness and knowledge are so measurable; the measurability criterion of these parameters is the resulting freedom.
Knowing the truth doesn't happen by luck, it comes from the power of spiritual awareness and spiritual knowing, which is a measurable and objective, developable faculty.
Your goal should be proving by yourself.
Don't talk about "man" the way the Jews do in their shitty books, "Man" is neither limited nor deceived.
Deception and foolishness is something of the enemy. The illusions have already been exposed, they are in the goetia.
What Maxine saw and felt perfectly was not induced by substances external to her, nor was she a patient.
She was a perfectly healthy person who, through meditation, was able to see the true appearance of the Gods.
The way you distinguish a God from a thoughtform, elemental, one's one mind, or any of these lesser creations, is you judge their ability. If you ask Satan for guidance on a matter and you receive a wise response, then you know this cannot merely be some sort of thoughtform or whatever.
This is further proven the more one works with them, which is why the Clergy can confidently issue statements about the Gods and the lower members can understand where this is coming from.