i go back to the house for a book

I Go Back to the House for a Book

I turn around on the gravel
and go back to the house for a book,
something to read at the doctor's office,
and while I am inside, running the finger
of inquisition along a shelf,
another me that did not bother
to go back to the house for a book
heads out on his own,
rolls down the driveway,
and swings left toward town,
a ghost in his ghost car,
another knot in the string of time,
a good three minutes ahead of me —
a spacing that will now continue
for the rest of my life.

Sometimes I think I see him
a few people in front of me on a line
or getting up from a table
to leave the restaurant just before I do,
slipping into his coat on the way out the door.
But there is no catching him,
no way to slow him down
and put us back in synch,
unless one day he decides to go back
to the house for something,
but I cannot imagine
for the life of me what that might be.

He is out there always before me,
blazing my trail, invisible scout,
hound that pulls me along,
shade I am doomed to follow,
my perfect double,
only bumped an inch into the future,
and not nearly as well-versed as I
in the love poems of Ovid —
I who went back to the house
that fateful winter morning and got the book.

--Billy Collins