The Nature of Science

This is an unusual post for StarStruck. Only one image, and that one more than 400 years old, and no videos. This is a speech I gave to Lynchburg College’s (now the University of Lynchburg) Senior Symposium class in 2010. I thought about editing it to take out references that were germane to that class, but I decided to leave it whole to provide context. It does have an astronomy tie-in. One of the readings assigned to the students was the passage in Galileo’s Starry Messenger where he describes his discovery of Jupiter’s four largest moons. That is the diagram that appears below before the text.

For your consideration.

 

Thank you, Dr. Freier. I have been fortunate enough to both speak to the Senior Symposium classes, and to teach them. It’s an honor and a privilege to do either, and I hope to do both again in the future.

I want to make a few points to begin with. I know that your task is to come up with a thesis, and use what I say today, along with your reading from Galileo, to support that thesis. The ideal talk from your point of view would be for me to say things with which you wholeheartedly agree, which you can quote, and which have an obvious connection with your reading. Second-best would be for me to say things with which you disagree so strongly that you take delight in tearing me apart and showing what a fool I am! The worst possible thing for me to do would be to go off on some tangent so bizarre that you can’t for the life of you figure out what it has to do with Galileo.

I’m going to try to aim pretty close to that first ideal, hoping that I can persuade you that I might know what I’m talking about, without being so obvious that your papers write themselves, and that everyone writes the same paper!

I’m also going old school with this presentation. No Power Point, just me talking and you taking notes. And if you’d rather just listen, or at least not try to write down every word I say, the text of this talk will be posted on Moodle later this afternoon.

So—what makes something science, and what makes something not science? When I think of this question, I am always reminded of Supreme Court Justice Potter Stewart who famously said of hard-core pornography “I shall not today attempt further to define [it]… But I know it when I see it.” Science doesn’t share very many traits with pornography, but perhaps it shares that one.
Let’s look at Galileo’s observations of the four largest moons of Jupiter to see if we can find some important characteristics that will let us call what he did scientific. First is the simple fact of observation itself. You can’t discover anything new if you don’t look. Now this may sound so blindingly obvious that it doesn’t even need saying, but it hasn’t always been so easily accepted. There is a story told about a discussion in a medieval monastery (the story is attributed to Francis Bacon), and I’m going to read this to you now:

In the year of our Lord 1432, there arose a grievous quarrel among the brethren over the number of teeth in the mouth of a horse. For thirteen days the disputation raged without ceasing. All the ancient books and chronicles were fetched out, and wonderful and ponderous erudition such as was never before heard of in this region was made manifest. At the beginning of the fourteenth day, a youthful friar of goodly bearing asked his learned superiors for permission to add a word, and straightway, to the wonderment of the disputants, whose deep wisdom he sore vexed, he beseeched them to unbend in a manner coarse and unheard-of and to look in the open mouth of a horse and find answer to their questionings. At this, their dignity being grievously hurt, they waxed exceeding wroth; and, joining in a mighty uproar, they flew upon him and smote him, hip and thigh, and cast him out forthwith. For, said they, surely Satan hath tempted this bold neophyte to declare unholy and unheard-of ways of finding truth, contrary to all the teachings of the fathers. After many days more of grievous strife, the dove of peace sat on the assembly, and they as one man declaring the problem to be an everlasting mystery because of a grievous dearth of historical and theological evidence thereof, so ordered the same writ down.

We can laugh at these disputatious monks, but we may not be much the wiser now. We’d rather Google it or find it on Wikipedia—those are our 21st century books and chronicles! Let’s just say, however, that observations of the natural world are at the heart of science. All the fine words in all the libraries of the world mean little in the face of what Galileo saw with his own eyes.
There’s more here, though. What did Galileo THINK he saw on the first night he looked at Jupiter? It seemed to him that there were three bright stars lined up with the planet: an odd arrangement, perhaps, but no more than that. But subsequent observations showed that these “stars” moved along with the planet against the background of more distant stars. Furthermore, they shifted their positions from night to night, and even within the same night. Sometimes there were only two that were visible, sometimes three, and sometimes even four. Their motions were not random; there were patterns in how they moved.

Galileo was not content simply to note these patterns; he sought an explanation for why they were occurring. It seemed apparent to him that the “stars” were in fact moons circling around Jupiter just as our moon circles around the Earth. If this were so, then their motion across the sky should be faster when they were closer to Jupiter from our point of view than when they were far from it, for reasons that Galileo explains and that I leave for your discovery.

Galileo then
1. Observed the natural world
2. Saw patterns in what he observed
3. Formulated a hypothesis to explain the patterns
4. Made predictions based on that hypothesis

The next step takes him right back to the top, making observations to see if those predictions are borne out. I’ve described this as a linear process, because one action leads to the next, but in fact it is circular. With Galileo, the first step was observation, but the process can begin anywhere. It will lead inexorably from one step to the next.

How about if we apply this means of investigation to the process itself? In other words, why do scientists do things the way they do? The most obvious answer, and the one often given when this question is asked of a scientist is: it works. It is a remarkably successful way of obtaining a consistent picture of how the natural world works. It automatically converges—maybe after many dead ends and false starts—on an explanation that works better than any previous ones. By working better, I mean that it both matches past observations and correctly predicts new ones.

But scientists also do things the way they do because of some assumptions of which they may not be aware. Scientists who have graduated from a liberal arts college and who have had the good sense to take philosophy courses—where you won’t be given the answers, but you will learn what the important questions are—these scientists are probably more aware than others of these hidden assumptions.

Can you trust your senses? Can you believe what your eyes and your ears tell you? With appropriate cross-checks and tests, scientists believe that you can. And instruments that extend our senses, like Galileo’s telescope, do just that—they make accessible to our senses phenomena too weak, or too distant, or too small for us to detect without their aid. They are different only in degree, not in kind; that is, they intensify signals so that we can detect them, rather than manufacturing something that wasn’t there to start with.

If someone tells me (and they often do) that they saw a really bright object in the western sky shortly after sunset, which is the most likely explanation: an exploding supernova, an alien spacecraft, or the planet Venus? Notice I didn’t say the correct one, I said the most likely! Neither a supernova nor an alien spacecraft is impossible, it’s just that the simplest explanation is the most likely one. This is what scientists and philosophers call Occam’s Razor (the razor that slices away unneeded explanations), and it can be summed up in the K I S S principle: Keep It Simple, Stupid.

How do I know that there is a real objective world out there that exists outside the confines of my skull? How do I know that all of you sitting in this room don’t cease to exist when I close my eyes? Essentially, I don’t. I just assume that is the case, because if I don’t, then doing science would be pointless.

Finally, scientists believe that the order they see in the natural world is discovered, not invented. Let me repeat that: scientists believe that the order they see in the natural world is discovered, not invented. I don’t just believe that the orbital period of a planet varies in a predictable way with its distance from the sun because of my position in the political power structure of my society. I believe it because it has been demonstrated repeatedly that planets behave without fail in this way and no other.

OK, this is our picture of what science IS. What about what it is NOT?

Let me ask you this: is the Big Bang theory scientific? This tells us that around 14 billion years ago, the entire universe consisted of an incredibly hot and dense entity no bigger than a grapefruit—and that this was after it had expanded enormously from even smaller dimensions. How is it possible that this is scientific when clearly there was no one there to observe it? Don’t we need observations, not just speculation or theory, for something to be called scientific?

Well…do you believe the American Civil War actually happened? If you are in Virginia, you had better believe it, even though you may need to call it the War of Northern Aggression! But if you do believe it, why do you? No one alive today could possibly have witnessed the Battle of Gettysburg, or the surrender at Appomattox.

Are the characters in all the various versions of CSI (Las Vegas, Miami, New York—I’ve lost count) doing scientific work? How can they possibly finger the murderer when they didn’t witness the act?
I hope you see the common thread in all these examples. There are certainly observations to be made, or to put it another way, evidence to be gathered from an event that has already taken place. The CSI cops can reconstruct that event from the evidence it has left behind. In the simplified world of TV, there will be only one possible event that could have produced the unique set of clues and evidence that they uncover. In the real world of historical research, we have all sorts of independent evidence of the American Civil War. To use Occam’s Razor, it makes more sense to believe that it really happened than that some giant conspiracy has planted all this false evidence.

The Big Bang has left clues as well. I won’t take a side trip here, tempting as it may be, to tell you all about them, but I can tell you that the way the universe is today constrains how it could have been in the past. We can make observations of the present-day universe and see the unmistakable traces of past events. Historical sciences are no less scientific because we did not directly observe the events we are describing.

Is astrology science? Can you determine what kind of day you are going to have by reading your daily horoscope? Let me just propose a test—if we had time, this group would be perfect for it. I would take the 12 astrological signs (I’m sure you know yours), and find horoscopes for yesterday. I’d list them without revealing what sign they corresponded to, and ask each of you to pick which one most accurately described what kind of day you had yesterday. I’d also ask you to put your birthday down along with your choice. How often do you think your birthday would correlate with the astrological prediction for that date? There are 12 astrological signs. If astrology is utterly without any merit, then you would expect that these would match up 1 out of 12 times—completely random. It’s sort of like a multiple-choice test where each question has four possible answers. You should be able to score at least 25% by not even reading the questions, just circling answers randomly. This is why 25% is not a passing grade on such tests.

Is evolutionary theory scientific? There are certainly people in Lynchburg who believe that it is not. There are even accredited departments of biology in our city who teach that it is not, who want you to believe that there is a legitimate scientific debate about whether all the wonderful variety and complexity we observe in the living world could have arisen by natural means. This is a subject too large to cover in any depth here. For one thing, the people who oppose evolutionary ideas are not even remotely in agreement among themselves. You have everything from folks who believe that Adam and Eve were real people and that the Earth is about 6000 years old, to ones who accept the great age of the Earth and of life upon it, and who accept the fact of creatures having emerged, evolved, and gone extinct, but who believe that certain biological structures and processes are too complex to have arisen without an intelligent designer. What all of these folks have in common, however, is a belief that natural processes are insufficient to account for what we see, that there must be something beyond nature—something supernatural—to explain what we do not understand.

The problem that scientists have with this point of view is not that people believe these things. Lots of people who are not stupid, not uneducated, and not crazy religious fanatics believe them, and many scientists believe some version of them as well. The problem we have is when people claim such beliefs are part of the scientific process, that scientific investigation has led them to these conclusions. Let me tell you why I think that assertion is ignorant at best, and deliberately dishonest at its worst.

Think about what supernatural means. Super means above or beyond—which means that Lynchburg College (going above and beyond) is a really super place! Natural means something is part of the world of nature that is accessible to our senses. Something that is supernatural is therefore not part of this natural world, not subject to its physical limitations.

But then it isn’t science. Science very precisely limits itself to just this realm of existence. It doesn’t deny the existence of the supernatural—scientists may, but science does not. It also doesn’t assert the existence of the supernatural. It is silent on the subject, just as the Chinese language is silent on the subject of the conjugation of French verbs.

I am no scholar of philosophy or theology, but I am a liberal arts college graduate. So I do know that the philosophical position of the creationists—that every complex structure requires a more complex designer—was demolished as least as early as the eighteenth century by David Hume. More fundamentally (I use that word deliberately), creationism and its latest evolved variant, intelligent design, is simply theology of a pre-modern era. It basically says that anything we don’t understand must have been done by something supernatural. If we don’t yet understand how something could be the result of natural processes, then it’s a miracle! If the human race had stayed with this sort of thinking, we’d still be explaining thunderstorms by talking about Zeus hurling lightning bolts.

OK. You may have figured out by now that 34 years of living in Lynchburg has made me a little passionate on this particular subject. But I have a deep love and respect for the great thinkers of both science and religion. I don’t like seeing their enormous contributions to civilization ignored or belittled.

Why would someone seek to validate their religious views by claiming they are scientific, anyway? It is a perhaps unconscious acknowledgement of the authority that science carries in the modern world. It’s not enough for some people to claim moral authority or to argue from a purely pragmatic standpoint. Your point of view must be shown to be supported by scientific evidence.

Science is indeed very powerful. It has created the modern world. I very likely would not have lived to adulthood had it not been for modern medicine. Just for a trivial example, I would have to talk a lot louder for all of you to hear me if my voice weren’t being amplified. But where does this power come from? Strangely, it comes from asking very simple, very limited questions about the natural world. What will happen when we mix a solution of lead nitrate and one of potassium dichromate? Does Mars have water ice just below its surface? Easy questions, really, although it may take some ingenuity to find the answers.

Are these the only questions worth asking? I don’t think so. I don’t believe that unanswerable questions are not worth asking. Each of us asks ourselves—or at least we should—why we are here, and what we are supposed to be doing. And some of us are still fine-tuning our answers, even when we are four decades older than most of you.

And the literal truth of science is not the only truth there is, either. There’s an important difference between these two questions: Did it really happen? Is it true? Did “Macbeth” really happen? Was there really a Scottish king who murdered his way to the throne with the help of his ambitious wife? Does it matter? Is Macbeth true? Does it tell us timeless and precious truths about ambition, and about guilt? I think so.

The power of science can lead to great evils, just as any power in the hands of fallible human beings can do. My own graduate field of nuclear chemistry helped hold the world under the threat of annihilation for most of my life, a threat that has diminished but has not disappeared.

Does science suck the beauty out of life? Not for me. Each scientist has his or her own way of finding beauty, of connecting with something larger than just one human being. For the biologist, it may be the intricate way a flower tricks an insect into carrying out reproduction for the flower. For a chemist, it may be the play of electrons that makes a particular group of atoms go here and not there on another compound. A physicist may find a set of equations that elegantly describe a phenomenon.

For me, it comes most readily under a dark night sky. To look up at what appears to be tiny pinpricks of light, and to realize that they are in fact nuclear furnaces, stars like our sun, their fires diminished by great distance, and to realize that their light has traveled to me for a thousand years—this is a numinous experience for me. There’s a new word for you—numinous. Look it up!

I want to finish with a story shared with me by my faculty colleague Dr. Eric Goff. The “story” is actually a multiple-choice question, and here’s the question:
There are many qualities that go into being a good scientist, three of which are listed here. Which one of these tops the list in importance?

The three possible answers are:
(a) having the courage of your convictions, whatever others may say
(b) building on the work of others
(c) being ready to question and investigate

And here is how a physicist responded: “Einstein displayed courage in his convictions, despite the criticism of others. Newton said of himself that he stood on the shoulders of giants. So A and B have merit. Even more important, however, and at the core of good science, is a readiness to question and investigate—traits that go with an open mind.”

They are also traits that your Senior Symposium teachers believe go with a liberally educated college graduate. You will be one of these two—a liberal arts college graduate–in a few months. We hope you are the other—a person with an open mind—as well.