Can't.

I hope to define my life, whatever is left,
by migrations, south and north with the birds
and far from the metallic fever of clocks,
the self staring at the clock saying, “I must do this.”
I can’t tell the time on the tongue of the river
in the cool morning air, the smell of the ferment
of greenery, the dust off the canyon’s rock walls,
the swallows swooping above the scent of raw water.

Jim Harrison