And the One resides in aeternitas, the no-time outside the arch of time. But I digress. Now, suppose you spend a lot of time among the Adepts, and learn Correspondence from them. To an Adept, there are no higher planes in any truly spiritual meaning, just levels of implementations. Yes, and that is the most dangerous thing about syncretism.
Most traditional philosophies are consistent, they explain and uphold reality.
But if you start mixing and matching, then you loose this consistency. The world no longer has to make sense, since you accept inconsistent positions. That was something completely different. But at least you are paying some attention in class. As I was saying, loosing consistency is very dangerous.