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‘I think scientists
should be humble.
They are not the
masters of today’s
knowledge.’
smallest possible units of the universe.
Finally, Rovelli argues, all objects—
even grizzly bears—have properties
only insofar as they relate to other
objects. “The world is not made of
stones,” he says. “It’s made of kisses.”
Work as a heart surgeon and you
can explain straightforwardly what
your job involves. Work as a theoreti-
cal physicist and you’re left resorting
to metaphor.
What makes things really challeng-
ing is that the universe does a good job
misleading us with what appears to be
simplicity. The ground is down there;
space—which has no grains as far as
we can see—is up there; time moves
forward. The trick for all of us, physi-
cists included, is not learning new
truths but unlearning old falsehoods.
The stem-winding title of Rovelli’s
new book comes from a 2016 essay in
which he visits a mosque in Senegal.
He removes his sandals before step-
ping inside the building, as directed,
but carries them inside with him. A
young man approaches him and points
to the sandals; Rovelli realizes that
the rule is actually that dirt- shedding
shoes should not enter the building at
all. He hurries back outside and leaves
the sandals behind. An old man picks
the sandals back up, places them in a
bag, and carries them into the mosque
himself to hand them back to Rovelli.
The man’s desire to put the traveler’s
mind at ease about his shoes has taken
precedence over even that rule.
The universe Rovelli has devoted his
life to explaining might be a cold, indif-
ferent, even unkind one—at least inso-
far as it largely limits us to our tiny little
beachhead of earth. But it is a clearer
and more elegant one for Rovelli’s ef-
forts. That, in a very real sense, is its
own act of kindness.