i think it means that you don't know anything unless you've experimented with it, therefore if you immediately know what something is then you must have already used that knowledge before,
"If you immediatley know the candle light is fire then the meal was cooked along time ago"
"if you immediately recognise candle light as fire, you must have seen fire before"
or as a metaphor for
"if you know what ascension is you must have ascended before"
also could be worded as
"you can't know what ascension is until you have done it"