48 | New Scientist | 20 November 2021things that we can uncover using
science and mathematics – that’s
already one enormous thing.” It seems
a fair bet that an inverse-square law
of gravity, say, exists in our universe
without us being there to say so. Why?
One answer might be some form
of anthropic selection principle
(see “Why is the universe just right?”,
page 41): only a regulated, predictable
universe is likely to provide the
conditions for questioning observers
to arise. Then again, some specific
aspects of our universe aid our
comprehension of it, but don’t seem
to be particularly crucial for our
existence. Take the fact that our
universe is expanding and evolving
from a big bang (see “Why is there
something rather than nothing?”,
page 37). That, plus light’s finite speed,
means we can peer out to different
distances and get a sense of what the
cosmos looked like in different eras
right back almost to the beginning.
Granted, that leads us to some
pretty dark places. To square what
we see with our models, we end up
proposing that 95 per cent of the stuff
in the universe comes in two entirely
mysterious forms, dark matter and
dark energy. Aren’t they a problem
for claims of an intelligible universe?
Not really, says Priya Natarajan at
Yale University. We might not know
what they are, but observation
demands something like them exist.
“I would call them placeholders,”
says Natarajan. “They are reminders
science is inherently provisional.”
For her, all of this leads us to a
glorious paradox. “Here we are witha gelatinous thing the size of a
cantaloupe inside our head, and yet
we have figured all this out,” she says.
That makes us very significant – and
yet these investigations have revealed
our sheer insignificance in a vast,
apparently lonely cosmos (see “Why
do we exist?”, page 38).
Davies thinks that leads in a
profound direction. “The universe is
able not only to be self-aware, but self-
comprehending: a microcosm of the
universe is able to comprehend the
whole,” he says. He thinks a pathway
from matter to the existence of mind
and comprehension is built into the
structure of the universe in some
fundamental way – a speculation he
admits puts him out of step with most
of his colleagues. “It’s the closest I will
get to any sort of religion,” he says.
Then again, there might be limits to
our comprehension. One big question
mark comes from quantum theory:
not least from the way it seems to blur
the strict separation between subject
and object, the observer and the
observed, that has allowed us to make
progress in understanding the wider
world (see “Why is quantum theory so
strange?”, page 44). “We don’t actually
have a framework to think about
science without these dichotomies,”
says Natarajan.
Perhaps the enormous progress we
have made in the past 300 years or so
in understanding the universe using
cast-iron physical laws is an aberration
that results from selecting a subset
of problems amenable to such an
approach. The quantum realm, our
own minds and complex systems
generally might be far tougher nuts.
“We could envisage in another
500 years people thinking: ‘That
was a quaint, old-fashioned way
of investigating the world, writing
down your equations and hoping to
make discoveries of Earth-shattering
importance’,” says Davies.
Already there are signs that the only
way to tackle such problems might
be using the data-crunching power
of artificial intelligence to uncover
patterns of correlation. Does this
mean that, in future, the universe will
be intelligible, but only by machines,
not directly by humans? Davies thinks
it is a possibility. “I hope that’s not the
case, I really do,” he says. “But I can’t
give you a proof.” Richard Webb ❚weren’t. We certainly wouldn’t be
asking the question; we probably
wouldn’t be aware of it being a
sensible question to ask. “What we call
‘intelligibility’ is a cognitive relation
we happen to have with the universe,”
says Carlo Rovelli at Aix-Marseille
University in France. “This isn’t
a question about the universe,
it is a question about ourselves.”
We are natural pattern-seekers,
this argument goes, because seeking
and understanding patterns in the
world around us has survival value.
“Our species, in its evolution, found it
advantageous to be curious, so we are
curious,” says Rovelli. Applying that
curiosity to the universe allows us
to see patterns there. Its intelligibility
is a product of biological evolution.
For others, that is only half the
story. “The remarkable thing is that
the world is not arbitrary or absurd,”
says Paul Davies at Arizona State
University. “There’s a scheme ofWhy is the universe
intelligible?
“ THE REMARKABLE THING IS THAT THE
WORLD IS NOT ARBITRARY OR ABSURD”