The road to the Palace of Wisdom is definitely not the road of excess.
That is the road to perdition that has led many souls astray.
In fact,the road to Wisdom is not even a road proper.
It is a hard and humble path.
. . . A narrow, winding and rocky path that few dare to climb and most overlook.
Originally Posted by Fast Gunn
I always thought the meaning of that quote was that sensual pleasure is a dead end but it can teach us that true happiness is not found in the material world. It's a spiritual irony that doing the wrong thing can result in wisdom. It's like an alcoholic that finally gets his act to together after he hits bottom.
Of course the problem with the path of excess is that, although it can lead to wisdom, it can also lead to oblivion.
To see a World in a Grain of Sand
And a Heaven in a Wild Flower,
Hold Infinity in the palm of your hand
And Eternity in an hour.
William Blake