"One philosopher asserted that he knew the
whole secret.
He surveyed the two celestial strangers from
top to toe,
and maintained to their faces that
 their
persons,
their worlds, their suns, and their stars,
were created solely for the use of man.
At this assertion our two travelers let themselves
fall
against
 each other, seized with a fit of
inextinguishable laughter."
That's from Voltaire's Micromegas in 1752




In the seventeenth century there was still
some hope that,
even if the Earth was not the center of the
Universe,
it might be the only "world."
But Galileo's telescope revealed that
"the Moon certainly does not possess a smooth
and polished surface"
and that other worlds might look
"just like the face of the Earth itself."
The Moon and the planets showed unmistakably
that they had
as much claim to being worlds as the Earth
does—with mountains,
craters, atmospheres, polar ice caps, clouds,
and, in the case of Saturn, a dazzling,
unheard-of set of circumferential rings.
After millennia of philosophical debate, the
issue was
settled decisively in favor of "the plurality
of worlds."
They might be profoundly different from our
planet.
None of them might be as congenial for life.
But the Earth was hardly the only one.

This was the next in the series of Great Demotions,
downlifting experiences, demonstrations of
our apparent insignificance,
wounds that science has, in its search for
Galileo's facts,
delivered to human pride.
Well, som hoped, even if the Earth isn't at
the center of the Universe,
the Sun is.
The Sun is our Sun.
So the Earth is approximately at the center
of the Universe.
Perhaps some of our pride could in this way
be salvaged.
But by the nineteenth century, observational
astronomy had made it clear
that the Sun is but one lonely star in a great
self-gravitating assemblage
of suns called the Milky Way Galaxy.
Far from being at the center of the Galaxy,
our Sun with its entourage of dim and tiny
planets lies in an
undistinguished sector of an obscure spiral
arm.
We are thirty thousand light years from the
Center.

Well, our Milky Way is the only galaxy.
The Milky Way Galaxy is one of billions, perhaps
hundreds of billions
of galaxies notable neither in mass nor in
brightness
nor in how its stars are configured and arrayed.
Some modern deep sky photographs show more
galaxies beyond the Milky Way
than stars within the Milky Way.
Every one of them is an island universe containing
perhaps a hundred billion suns.
Such an image is a profound sermon on humility.
[Pause]
The long standing view, as summarized by the
philosopher Immanuel Kant,
that "without man the whole of creation would
be a mere wilderness,
a thing in vain, and have no final end" is
revealed to be self-indulgent folly.
A Principle of Mediocrity seems to apply to
all our circumstances.
We could not have known beforehand that the
evidence would be,
so repeatedly and thoroughly, incompatible
with the proposition that
human beings are at center stage in the Universe.
But most of the debates have now been settled
decisively in favor of a position that,
however painful, can be encapsulated in a
single sentence:
We have not been given the lead in the cosmic
drama.
Perhaps someone else has.
Perhaps no one else has.
In either case, we have good reason for humility.
