MONDAY, JULY 19, 2021
It may still be early: Explaining the cosmos has never been easy. Right at the start of his massive 1988 best-seller, A Brief History of Time, the late Stephen Hawking offered a whimsical alleged example—a whimsical alleged example from fairly modern times.
It's widely agreed that Hawking was one of our most brilliant physicists. He also had a flair for whimsy. In the very first paragraph of his book, he offered this example of an attempt to explain the world:
A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: “What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise.” The scientist gave a superior smile before replying, “What is the tortoise standing on?” “You’re very clever, young man, very clever,” said the old lady. “But it’s turtles all the way down!”
That was Hawking's very first paragraph. To read the first half of his first chapter, you can just click here.
Hawking's anecdote involved some stereotypical types. For better or worse, it pitted the hopelessly daft "little old lady" against the supercilious high-end professor who thinks he knows it all.
If we regard this anecdote as anything other than whimsy, an apparent disregard for actual fact is an additional part of the mix. Accepting this whimsical tale on its face, Hawking is willing to assert that a well-known scientist was confronted this way—but he isn't quite sure which one!
Presumably, this amusing anecdote is whimsy all the way down. But as he continues, Hawking makes an intriguing remark about our current state of certainty concerning the warp and woof of the world—of the universe or the cosmos:
Most people would find the picture of our universe as an infinite tower of tortoises rather ridiculous, but why do we think we know better? What do we know about the universe, and how do we know it? Where did the universe come from, and where is it going? Did the universe have a beginning, and if so, what happened before then? What is the nature of time? Will it ever come to an end? Can we go back in time? Recent breakthroughs in physics, made possible in part by fantastic new technologies, suggest answers to some of these longstanding questions. Someday these answers may seem as obvious to us as the earth orbiting the sun–or perhaps as ridiculous as a tower of tortoises. Only time (whatever that may be) will tell.
"Only time (whatever that may be) will tell!" Given the title and subject matter of his book, Hawking was adding an additional measure of humor as his book's second paragraph ended. But as he did, he offered some observations which may resemble a warning:
Some of the things we believe today may turn out to be as ridiculous as that tortoise tower. Some of the things we believe today may turn out to be wrong!
Quite literally, that's what he said. It seems to us that that was a sensible warning. Indeed, it's quite conceivable that Hawking's wholly sensible warning isn't quite strong enough!
Within the western tradition, explaining the universe has always been hard. In the beginning, it was hard, and it's still hard today.
Our human reasoning capability has always been limited, flawed. Consider a portrait Hawking presents on the second page of his book, where he visits the man who, if only by inference, can be described as "the greatest logician until Gödel came along."
Within the western tradition, Aristotle is widely and sensibly viewed as the first great logician. According to Hawking, he also reasoned in such ways as this:
Aristotle thought the earth was stationary and that the sun, the moon, the planets, and the stars moved in circular orbits about the earth. He believed this because he felt, for mystical reasons, that the earth was the center of the universe, and that circular motion was the most perfect. This idea was elaborated by Ptolemy in the second century A.D. into a complete cosmological model...
The greatest logician formed this picture of the universe in accord with things he believed "for mystical reasons." A bit later in his opening chapter, Hawking visited Aristotle again:
According to a number of early cosmologies and the Jewish / Christian / Muslim tradition, the universe started at a finite, and not very distant, time in the past. One argument for such a beginning was the feeling that it was necessary to have “First Cause” to explain the existence of the universe...
Aristotle, and most of the other Greek philosophers, on the other hand, did not like the idea of a creation because it smacked too much of divine intervention. They believed, therefore, that the human race and the world around it had existed, and would exist, forever.
Aristotle didn't like the idea of a creation "because it smacked too much of divine intervention."
Hawking doesn't say why Aristotle disliked that idea so much. But in some of these areas, Aristotle's approach is starting to sound like reliance on mystical beliefs a good part of the way down.
Nor did the types of reasoning we might regard as faulty come to a sudden end in the time of the ancients or by the shores of the Aegean. In the second chapter of his book, Hawking notes that Isaac Newton—the greatest physicist prior to Einstein—was "very worried by" a certain idea about "absolute space" (whatever that may be) which emerged from Galileo.
Newton was very worried by the idea that absolute space did not exist "because it did not accord with his idea of an absolute God." Without any question, Newtown was one of the history's greatest intellectual giants. But his reliance of that idea will likely sound like a type of faulty reasoning.
Meanwhile, Hawking warmed the cockles of our heart with another observation in his opening chapter. Was even Hawking allowed to say this? We're not sure, but on page 8, he did:
The question of whether the universe had a beginning in time and whether it is limited in space were later extensively examined by the philosopher Immanuel Kant in his monumental (and very obscure) work Critique of Pure Reason, published in 1781...
As Hawking continues, he describes Kant reasoning in ways which might seem faulty today. Just for today, ignore that!
In that passage, Hawking voiced a rather puckish view about Kant's extremely famous book. He dared to describe the famous book as being "very obscure!"
That warmed the cockles of our heart. Not to boast, but we formulated the very same view when we were still in college, in October of junior year!
Describing the cosmos has always been hard. Right from the start, our capacity for reason has always been limited. Often, it has been faulty.
Presentations which seem like explanations may reach imperfect ends. Consider the basic stuff of the universe.
At the dawn of the west, Leucippus and his pupil Democritus proposed that all matter was composed of atoms. The leading authority on the topic goes into more detail:
In the 5th century BCE, Leucippus and his pupil Democritus proposed that all matter was composed of small indivisible particles called atoms. Nothing whatsoever is known about Leucippus except that he was the teacher of Democritus...Democritus's argument for the existence of atoms hinged on the idea that it is impossible to keep dividing matter for infinity and that matter must therefore be made up of extremely tiny particles.
"Democritus's argument for the existence of atoms hinged on the idea that it is impossible to keep dividing matter for infinity." This argument makes a type of sense as far as it goes, which may not be all that far and may not be all the way down.
Democritus' reasoning let him stop torturing himself with pictures of an infinite process of the division of matter. This may have let him sleep better at night, but it left us with a type of problem:
We were now asked to posit a type of entity no one had even experienced before—a type of entity which couldn't be divided further or reduced in size.
One can always imagine or say that some such entity exists. But one is also forced to admit that he or she has never encountered any such entity, and he or she may soon be asked why the hypothesized type of entity can't be reduced in size.
We're thereby left with a new mystery—with a mystery to be solved later. In that sense, we haven't been taken all the way down.
In our view, a similar problem lurks today with our possibly somewhat vague understanding of history's most famous equation: E = mc2.
In essence, and colloquially, that famous equation tells us that matter can be converted into energy. A very large "mystery to be solved later" may be lurking in that formulation, but let's leave that one for later.
Hawking began his book with a portrait of the classic querulous lady offering a fairly ridiculous view of the cosmos. Very quickly, he warns us that our own more advanced current views may some day turn out to wrong—may even come to seem "as ridiculous as a tower of tortoises."
That strikes us as sage advice. It's also true that many of the ways in which modern physics is described may perhaps be a bit incoherent. Given the follies of human reason, these presentations may be less than coherent pretty much all the way down.
Has anyone ever been able to explain Einstein to the general reader? For the most part, we're going to say that the answer is no, but the story doesn't end there.
Even at the highest ends of journalism, academia and publishing, very few people have ever been willing or able to notice and acknowledge this fact. A serious cynic might see it this way:
They keep pretending to make Einstein easy and we keep pretending to get it.
Was Aristotle's reasoning sometimes flawed? No doubt, but so is our own. When human reason swings center stage, the pitfalls are everywhere.
Tomorrow: Brian Greene's extremely clear statements
The past is prologue: Last week, we started with Richard Cohen's "miracle column." In his column, Cohen said he didn't understand Hawking's widely-praised, best-selling book.
Five months later, Charles Krauthammer said the same thing. Our ruminations started here. They'll continue along this week.