I have already solved this
first you must pass the self-awareness test,that is to light the three pillars.
then it will show you three books,to solve the riddle of library ,you must infer to the books..
now I will show you
first:light all the candles except the middle one,until a lightning strikes
second:light only the middle candle,and wait for the lightning
last:light any three candles,and wait for the lightning
the gate will open
im not sure you talk about what he means,
anyway im not sure if i do, but if you mean the room with the closed room inside where a leandras diary lies on a pillar then the riddle solves like this and why.
In this room ( library ) you find a book " the necronomicon of cooking" read it:
It is written by E.N.S West ( thats his name lol )
on the stairs you see a big compass but the northsymbol points towards the right, which is east according to your minimap compass.
In this library there are 4 hidden pressure buttons.
On right by the stairs beneath the middle coal..light
one on the right wall from the middle room
one on the top side of the room on a wall.
and the last one left-upper side of the room also on the wall.
NOW imagine this 4 buttons like they are placed in the directions north east west south and so on.
PLUS think of their directions not with your minimap but with the stone-compass on the stairs, like the directions are changed to 90ｰ to the right.
then remeber the book E.N.S West.... which means east norht... etc. so press the buttons in that order.
translated to your minimap: first the one beneath the cole, then the one on the wall from the inner room, then the left-upper one and at last the upper one. The magical wall disappears...took me 30 minutes and 1.230.043 nevers.