- Physicists are in a funny position
of having to think creatively
and imaginatively with the strictest limitations
of reality.
That can lead to very confining ways
of approaching physics to only work within the known laws.
And that can also lead to a kind of explosion of creativity;
and that has also been phenomenally successful.
The world is so different
than we thought it was 100 years ago,
and certainly 200 years ago,
that even the most brilliant minds, the greatest geniuses
of 200 years ago, if they told physicists not to dream,
not to imagine, that would be absurd and small.
And so I believe there's always a place
in science for people who are manifestly dreaming
about things that may never be observed.
We realize we're not at the center of the Universe,
and we realize that our solar system isn't unique.
When Einstein was working in 1905, he did not know
for sure that there were other galaxies out there.
And now as far as the eye can see, there are galaxies.
There are as many galaxies in the observable Universe
as there are stars in the Milky Way.
And the question becomes, and it's a natural question,
"Is this the only time there was a big bang?"
"Is this the only Universe,
or are there an infinite number of universes?"
"Is nature just constantly playing the slot machine?"
And yet, it's an important question to ask,
because some of our pursuits in the uniqueness
of the laws might be futile if we begin to understand
that there are some things that are just random seeds.
So we have laws of physics, but maybe the mass
of the electron is just a random accident.
And so the question arises, "Are we rare
in the multiplicity of universes, or are we likely?"
And we can ask those questions,
and we can answer them theoretically.
There is a criticism that's often levied
against very theoretical work because
if, by definition, we can never observe the multiverse,
then some people would argue, technically,
it's not a scientific pursuit.
Because as human beings,
we've come together and we've decided
that there's certain scientific methods that work best,
and that there is reproducibility as a requirement,
and that it needs to be true for all of us,
and that we all can own these ideas and these concepts,
and that somehow the multiverse isn't falling
within that category.
And I think that is one
of the extreme cases where we have
to just shrug our shoulders and say, "Nature doesn't care
if it satisfies our criteria for science."
It just might be the way that it is-
and we just might have to accept that.
There's an element
of fairness when observational physicists criticize
theorists who are so far removed from experimentation.
And we will often be reminded:
Huge advances really are driven by experimentation.
And I have tremendous respect for experimentalists.
I spent a lot of times around certain experiments,
marveling the collaboration that led to it,
and the technological sophistication, and the faith,
and the laws of physics that I play with on paper.
But the faith that they're real,
and that you could build something.
There's an entire history of astronomers going back decades
and decades discovering dark matter before the sort
of theoretical community was willing to accept the absurdity
that most of the matter in the Universe was not made
of anything we have ever seen before.
And yet it was discovered by something as direct
as looking at the orbits of stars around galaxies,
and realizing that there's missing mass, that there's a lot
of mass that cannot be accounted for by anything luminous.
We don't know what it is.
We don't know what it means.
If it's just the tip of the iceberg
that there isn't just dark matter,
but maybe there's an entire 'dark reality,'
that world would be completely invisible to us,
except for our gravitational interaction-
And that is a really solid observational, scientific result,
and yet we theorists, we still don't know what it is.
It's really the tension between the two
that keeps us honest.
It's the experimentalists confirming discoveries
to keep us going and to rule out certain directions.
And the theorists listening to the experimentalists
and following those discoveries, use them as pullies
and hoists to scale this great mountain,
which is trying to understand the cosmos.
And I think that ultimately, scientists are open
to nature being stranger than fiction.
We simply cannot live in societies of ignorance, limitation,
and some of the things that that begets,
including feudalism, tribalism, violence.
All of these sort of negative sides of our primates selves
are challenged and put into perspective
when we make these tremendous discoveries.
We begin to rewrite our values, our social theories.
Once people have that experience of looking out
into the cosmos, you kind of can't unlearn what you've seen.
And I do think it has an effect on all
of us, both personally and culturally and globally.