How can we know the dancer from the dance?

Labour is blossoming or dancing where
The body is not bruised to pleasure soul.
Nor beauty born out of its own despair,
Nor blear-eyed wisdom out of midnight oil.
O chestnut-tree, great-rooted blossomer,
Are you the leaf, the blossom or the bole?
O body swayed to music, O brightening glance,
How can we know the dancer from the dance?
— Among School Children, W. B. Yeats

Dante's Inferno series — William Blake

 

Midway upon the journey of our life
I found myself within a forest dark,
For the straightforward pathway had been lost.
Ah me! how hard a thing it is to say
What was this forest savage, rough, and stern,
Which in the very thought renews the fear.
So bitter is it, death is little more;
But of the good to treat, which there I found,
Speak will I of the other things I saw there.
I cannot well repeat how there I entered,
So full was I of slumber at the moment
In which I had abandoned the true way.
But after I had reached a mountain's foot,
At that point where the valley terminated,
Which had with consternation pierced my heart,
Upward I looked, and I beheld its shoulders,
Vested already with that planet's rays
Which leadeth others right by every road.