Key insights from
The Grand Design
By
Leonard Mlodinow, Stephen Hawking
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What you’ll learn
Why are we here? What is reality? Why is there something
instead of nothing? Stephen Hawking and Leonard Mlodinow team up to
champion science as humanity’s best hope for answering questions about our
existence and the existence of our universe.
Read on for key insights from The Grand Design.
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1. Science—not
philosophy—provides answers to life’s biggest questions.
Philosophy is dead. It’s failed to keep pace with science
and its amazing, rapid development—particularly in the field of physics. We
must look to science for answers to our biggest questions about life and
the universe. Science alone can tell us why there is something rather than
nothing, why we are here, and whether the universe needs a creator. It will
increasingly be the torch that leads us out of the cave of ignorance. It is
important to understand the how, but it is even more critical to
know the why. The curious human species has always grappled with
these questions, and thankfully science is becoming increasingly capable of
providing the answers.
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2. The physicist’s
dream of a single theory of everything is unlikely to be realized.
Gravity was the first force articulated in a mathematical
formula. Sir Isaac Newton published a paper on the subject in 1687. Newton
maintained that all objects in the universe will attract each other in
accordance with the mass of the objects. The formula he used to model this
made waves in his day because people realized that at least one force in
the universe can be understood mathematically. This raised questions of
whether other formulas could be expressed mathematically as well.
Maxwell’s theory of electromagnetism is another landmark
discovery, and perhaps the most significant for the human race from a
commercial perspective. Maxwell’s equations have allowed us to use
electromagnetism for all kinds of common household appliances and
computers. What is more, they’ve enabled us to understand the diverse
spectrum of wavelength frequencies, from radio and microwaves to gamma
waves.
Einstein’s theory of relativity was another important
contribution to the discussion of physical forces. He showed that Newton’s
assumption that objects move along a straight path is mistaken, that
objects move not in straight lines but on geodesics—that is, along curved
lines. An example of this principle at work is flight trajectories. Looking
at a 2D world map, the routes that planes take look circuitous, when, in
fact, the curved trajectory is the shortest distance.
Newton, Einstein, and Maxwell each developed models that
comprise a corpus of classical theories. Each was an attempt to develop a
unified theory of everything. Unfortunately, these models do not explain
phenomena at an atomic and subatomic level. To better grasp these
phenomena, scientists have had to turn to quantum theories. We need quantum
theories of gravity, electromagnetism, and relativity. While vital to our
understanding of the universe, the classical models only get us so far.
Quantum field theories will take us farther. String theory was an attempt
to develop a unique theory of everything, but there are a variety of string
theories, and they are incompatible with each other. Advocates still hold
that these different “strands,” if you will, of string theory are all
circling in on one underlying super theory, with each of these strands
applicable to differing scenarios.
This underlying theory is referred to as M-theory. What does
the ‘M’ stand for? No one seems to know. M-theory is a collection of
theories, which, taken together, could bring us a theory of everything.
It’s probably the closest we will come to realizing the physicist’s hope of
a single, unified theory of everything. We’d like to ascertain the exact
nature of M-theory, but it might not be possible.
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3. The Big Bang
theory is an important, misunderstood scientific milestone.
Different people groups from civilizations around the globe
and across time have constructed a variety of creation narratives. These
stories try to make sense of why there’s a universe and why this particular
universe and not another.
Within the last century, we have made remarkable strides
toward answering these questions. Recent discoveries and theories like the
multiverse, M-theory, and alternative histories equip scientists to posit
promising explanations.
Perhaps one of the most significant discoveries of the past
century is that the universe is not static, but dynamically expanding. In
1920, Edwin Hubble became the first to notice this in an observatory in
Pasadena. Based on the spectrum of light that galaxies were emitting,
Hubble realized that galaxies were moving away from each other, and those
farthest away were moving at the fastest rates.
This was the first clue that the universe began to exist.
Trace the expansion back as far as you can and you will reach a point of
unfathomably dense energy, from which propelled the emanation of what
became space and time. This expansion would not affect the size of objects
themselves, but just the space between them.
The idea of an initial ‘big bang’ was novel for Einstein and
his contemporaries. But it was not without its detractors, as it would have
meant reevaluating some basic assumptions about the universe. Even the
astrophysicist who coined the term ‘big bang’ in 1949, Fred Hoyle, intended
it to be pejorative. It’s since become common parlance, used
matter-of-factly rather than dismissively.
Further confirmation of the big bang came in 1965 with
discovery of CMBR, or cosmic microwave background radiation. This radiation
is residual from the very early universe. That being said, it would be
misguided to conceive of the big bang as a literal explosion from a
particular point of origin. We can use general relativity to make
observations about a young universe, and how it unfurled over space-time,
but it cannot tell us exactly how the universe began. Quantum theory is
more helpful for understanding what was going on at the very beginning
because it applies when our scope is atomic and subatomic. Go back to when
the universe was a billion-trillion-trillionth of a centimeter, and quantum
mechanics is helpful, whereas Einstein’s relativity breaks down.
Clarification on the word "beginning" is also
important. Aristotle and other philosophers have side-stepped the question
of creation by assuming the universe is eternal. Others have attributed the
universe’s beginning to a creator God. The particular unfurling of the
early universe involved four dimensions of space and none of time. This
makes talking about the “beginning” a tricky business, as time itself
didn’t exist. This leads us to conclude that the early universe was brought
about by the laws of science—not by some creator.
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4. We’re not as
special as we thought—there are likely other inhabitable planets in other
galaxies and universes.
Universes in which life is possible are extremely rare,
arguably miraculous. Our solar system, more specifically, contains numerous
attributes conducive to complex life forms. Consider earth’s path around
the sun. Kepler had hoped that planets in our solar system orbit in perfect
circles, but went on to discover that they actually revolve on ellipses or
slightly “squashed” circles. If the shape of the ellipse on which
earth orbited were too squashed, earth would come catastrophically close to
the sun. Another serendipitous factor is earth’s distance from the sun. If
the earth were a bit closer or further to the sun, life wouldn’t be
possible. The size of the sun also makes a difference. If the sun were
slightly larger, earth would get hotter than Venus; a little smaller, earth
would freeze over and be colder than Mars. In either case, earth would be
utterly uninhabitable. Earth fits squarely into what scientists call the
“Goldilocks’ Zone”: the narrow range of conditions in which a place is
inhabitable, where it’s not too hot, not too cold, but “just right.”
As with the discovery of the universe’s beginning, many are
tempted to attribute the apparent fine-tuning of the universe to a creator
who has intentionally designed it to be so. Before we conclude that we are
a special species, it is important to keep in mind not just the chance, but
the likelihood of planets within other galaxies supporting life. Add in the
real possibility of the multiverse and we see that it is not only
conceivable, but very likely that we are far from the special planet at the
center of the universe as we would like to think. This detracts from the
idea that a God has intentionally created earth to be a singular planet on
which life emerges.
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5. Scientific
determinism is true, but free will remains a useful fiction.
Do these creatures have free will? If we came across an
alien, we might wonder if it’s a complex robot or a complex creature with a
mind of its own. In the case of a robot, it doesn’t have free will because
we can predict its actions. With complex beings, however, we are forced to
concede free will because it is a helpful model. Our predictive abilities
are limited when dealing with staggering complexity. We have a hard time
predicting the interplay between three particles, and human beings are
comprised of trillions of particles, making behavioral predictions all but
impossible. Free will is a useful fiction we must maintain until we can
develop equations complex enough to accurately predict behavior. But this
is admittedly a monumental and perhaps impossible hurdle.
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6. The law of
gravity explains why there is something rather than nothing.
Physical laws describe how the universe operates,
but they cannot tell us the why behind the existence of something
rather than nothing, or why humans are part of that something rather than
nothing. Here again, God the creator is the easy escape clause, but this
creates (pun intended) a problem of infinite regress: if God created the
universe, then who created God? And then what created that Being that
created God? We are now able to answer questions within a scientific
framework instead of resorting to a mystical explanation that raises more
questions than it answers.
We now know that the universe spontaneously gave birth to
itself. It is because of this spontaneous self-creation that we have
something instead of nothing. This is the explanation for the existence of
our universe; it is why we’re here. We now know that the laws of nature,
specifically the law of gravity, gave rise to the universe’s spontaneous
emergence. The universe’s energy must stay at a net zero. As energy is
required to form matter, it would seem inconceivable that anything—let
alone an entire universe—would emerge from nothing. Gravitational energy,
however, is negative, which would balance out the positive energy needed to
create matter. Thus, we have the possibility of a universe coming from
nothing, a possibility that has clearly been actualized.
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Endnotes
These insights are
just an introduction. If you're ready to dive deeper, pick up a copy of The Grand
Design here. And since we get a commission on
every sale, your purchase will help keep this newsletter free.
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