Here is a poem by Gerald Stern.
as a piece of paper blown around by the wind,
and I loved the sight of it sticking to a tree,
or jumping into the backseat of a car,
and for years I watched paper leap through my cities;
but yesterday I saw the mind was a squirrel caught crossing
Route 80 between the wheels of a giant truck,
dancing back and forth like a thin leaf,
or a frightened string, for only two seconds living
on the white concrete before he got away,
his life shortened by all that terror, his head
jerking, his yellow teeth ground down to dust.
his great purpose and the alertness of his dancing,
that showed me the difference between him and paper.
Paper will do in theory, when there is time
to sit back in a metal chair and study shadows;
but for this life I need a squirrel,
his clawed feet spread, his whole soul quivering,
the loud noise shaking him from head to tail.
O philosophical mind, O mind of paper, I need a squirrel
finishing his wild dash across the highway,
rushing up his green ungoverned hillside.