William Blake, Songs of Experience: The Voice of the Ancient Bard
Youth of delight come hither. 
And see the opening morn, 
Image of truth new born. 
4
Doubt is fled &  clouds of reason. 
Dark disputes &  artful teazing , 
Folly is an endless maze, 
Tangled roots perplex her ways, 
8
How many have fallen there! 
They stumble all night over bones of the dead: 
And feel they know not what but care; 
And wish to lead others when they should be led.