In 1988, Stephen Hawking gave the world A Brief History of Time. Now Sean Carroll goes From Eternity to Here.
Artists and physicists both share a sense for the incomprehensible. Artists for the boundaries of the human mind, but physicists also for that boundary, and beyond that space and time too. The ordered life, free of all but the most practical matters, confuses experience with expectation, and we claim we know things that we only think we know, but physics tends to flout the superficiality of mere experience.
The nature of a thing cannot be known just by watching it, which is why the emergence of a quantifiable science throughout human history posed such a thorny endeavor, so any idea that is both unique and profound requires a mind equally proficient in these qualities, which is a virtue. For anyone who follows the never-ending ego-stroke of politics, sometimes it is with a semblance of relief to be reminded that there are some things man cannot conquer. But if we are ever able to conquer the mysteries of the universe, then I hope that it is men like Sean Carroll who do the conquering.
Bound by a similar spirit as Hawking, Sean Carroll inspires and amazes with From Eternity to Here, a challenging book which requires an open mind and a love for exploration that is both metaphysical and scientific in nature. Maybe science isn’t the same as metaphysics, but the questions imposed by Carroll cannot resist from the reader a certain expectation for an out of body experience. Sometimes the universe seems so immense and incalculable that the mind strains against limitations just to take it all in. The feeling of awe just becomes too broad and elastic.
Carroll is a physicist and not a writer, so he communicates with the contemplation and quiet humility of a scientist considering the natural world. Since his subject is so complex, he continuously stacks concepts on top of one another, each an answer to the previous question. I think that someone like Lawrence Krauss can explain things with more of a natural ease and simplicity, but Carroll is a worthy tour guide, and the book itself is an immense reward. Veterans of physics will have an easier time, but it is written in such a way that it is accessible to those who may only vaguely recall some of these concepts from high school physics class (pictures and diagrams within the book are handy illustrators but may go too far with a diagram of three dimensional space). This is not a static experience. I had the longing impression that I had made a contribution to the arguments and felt along its edges intellectually with a more open and fluid mind, even if that feeling was merely an artifice, for Carroll has presaged every question, including some that I had never considered asking.
A journey of this kind of ambition needs breathable space in which to work, so some of the scientific rough edges are mollified by an interesting use of art and literature; the very name of the book is a reference to the famous novel by James Jones. In fact, art makes a noble bedfellow with physics. Because we are not literal explorers, we must imagine ourselves in those places of the universe that cannot be visited and may only be theoretical. Stories like The Curious Case of Benjamin Button and Einstein’s Dream, both of which Carroll invokes within the book, literally strip the laws of physics and the arrow of time of any power to affect us in such a rudimentary way as linearity. We explore in ways greater than that.
For Carroll it is not so easy. He is constrained by the limitations of the known universe. But he explores a great deal of concepts such as light cones, quantum mechanics, and general relativity in order to arrive at the ultimate theory for the beginning of time and the state that the nascent universe found itself in moments after the Big Bang. The most provocative concept is entropy and time reversal. Like the backwards-oriented soldiers in The Curious Case of Benjamin Button, where time itself may dislodge bullets and send each man back home to their families, it is no less than the power to do undo things. Imagine the man in the Old Spice commercial riding forward on a backward horse. Effect precedes cause. We care to think of the future as unwritten, but the future is nothing more than the sum total of its past manifestations. To know the movement of atoms and particles in the past is to predict the future, even if it hasn’t yet happened, and the central question of entropy binds it all together.
There are many ways to think about entropy. The concept was initially expressed in terms of thermodynamics: heat will flow into cold but not the opposite. It has also been thought of as a trend toward chaos, and many people may want to say that their lives increase in entropy, but this is also an inadequate expression since chaos can be low-entropy too. Neither is entropy just a state of equilibrium. Perhaps a good way to describe it without invoking a long, scientific explanation is the uselessness and inability to do work. Once a bottle of perfume opens, it will settle into the air, which is its most likely state of configuration, and everything about our experience tells us that it will not flow back. But entropy is merely a tendency, and if time were an inscrutable thing, having no affect upon us so that we may observe its passage in years that can only be expressed in large exponents, the perfume may, in fact, go back into the bottle.
Because the perfume is initially in the bottle, and because the rest of the universe does not seem to exist in a state of maximum entropy, it most likely evolved from a state of low entropy, which accounts for every moment since the Big Bang. It is the thing before the Big Bang that galvanizes physicists to search for more complete theories of the universe. Carroll cannot answer every question (I’d like to think that our universe is alone, and in lieu of that I’m partial to the baby universe explanation), but readers should also feel stimulated and enthralled when he asks them. After reading the book, maybe eternity won’t feel so long after all.