It is a conjecture for those who haven't REALLY investigated it.

In this investigation, reading isn't the protagonist. It is necessary, but it's not enough. One needs "weeding" (because a lot of BS has been written about it), experimenting on what's left after the weeding, connecting dots with data from other fields, too (including science), testing and testing again by personal action and inner work, bringing tangible proof to yourself, etc.

The elucidation has to be the result of personal research, not something taken from an ancient book. Those that were really expanded to wider levels of consciousness, didn't leave writings to persuade the next generations, but to express that this is possible, to trigger someone to begin their own investigation. Because the destination is the same, but the paths are different; each one goes there walking on a personal path that is constructed with his/her action as a basic factor.