A proposition offered by Wilson on the nature of the human mind - "Whatever the Thinker thinks, the Prover proves."
"Of course it is fairly easy to see that other peoples minds operate this way; it is comparatively much harder to become aware that one's own mind is working that way also."
Realize that when you think X, all of your successive thoughts attempt to reconcile or solidify the notion of X. In this way, we are the artists of our realities, everyone's reality being different than others since all of it is based on conceptions. Your conceptions and ideas rule you, from who you think you are to what you think the world or your environment is about. It is how you make sense of all sensory data. Not everyone organizes their reality in the same way you do, because they all went through a difficult accumulation of sense data (and subsequent reaction to and organization of said data) throughout their lives to get to where they are.
More: http://deoxy.org/wiki/The_Thinker_and_the_Prover
The question then becomes, can we then transcend our conceptions and perceive reality as it is? We may have to consult the Buddha on this one.
One of the most interesting things about reading Robert Anton Wilson's more autobiographical stuff (Cosmic Trigger? Prometheus Rising?) is that when he talks about doing LSD for the first time with Leary and co, all these guys were in their 30s!! I can't imagine how shocking it would be to have gotten that far in your life, believing and committing to the perceptions you've had, only to have them ripped apart by those megadoses (by today's standards) of LSD.
I think that is also why they made such good use of the experiences. Having more life experience, they might have been even more appreciative of the new insight.
http://www.amazon.com/Prometheus-Rising-Robert-Anton-Wilson/...