Definitely true. But also remember that the filtering function of the brain is necessary, as an overwhelming level of sensory input would make it impossible to function. Entheogens work a lot to open up our minds channels within itself too. Connections that are unconscious and obscured become clear and discernible. We can learn new truths and gain new insights which we can, with work, carry with us back into sobriety (if we ever choose to return

).
I wish i could remember my insights on drugs as easily as i can remember my day to day life (not to great, but thats a different story

). I guess if it were that easy revelations wouldn't have the same value they do though.
The opening of the mind isn't the action of the entheogen or empathogen, its a contract between the mind open to receive and the chemical willing to give. Drugs don't impart wisdom, they uncover it.
weed is like a pair of glasses for the third eye. society has rendered many shirt-sighted.