The science talk

Here’s a talk I gave to my descriptive astronomy students on the nature and limits of science.  Suggestions on how to improve it for my next batch of students are welcome.

And now, a word of self-justification.  I know many of you are annoyed with me for making this introductory course harder than you expected.  We haven’t just been looking at pretty pictures this semester.  You’ve been forced to acquire a real understanding of things like blackbody radiation and Newtonian gravity.  You’ve had to reproduce the analyses of some of the pivotal orbital and spectroscopic measurements that establish the key results of this field.  Why did I do this to you?

First of all, because college is not meant for everyone; it’s meant for the intellectual elite, so you should expect that all of your professors will expect a lot more of you than your high school teachers did.  More importantly, this course satisfies your science graduation requirement–I realize that’s the reason a lot of you took it–and the purpose of this requirement is to expose you to the scientific enterprise and the sort of reasoning that’s proved effective for quantitative, empirical fields.  As you’ve seen, the scientific method is an incredibly powerful tool, one which you may find useful in your own fields.  Regardless, you will be forced to deal with scientists and scientific claims later in life, whether as a consumer, a patient, or a citizen.  You need a clear idea of how this “voice of science” is to be treated, and for that, I thought you needed a peek “under the hood” to see what sort of reasoning and testing underlie one real scientific discipline.

Some of the points for you to take away are

  • Scientific results have varying degrees of certainty.  Some things are extremely well tested.  At this point, we can be extremely confident about Kirchhoff’s laws, the H-R diagram, or the existence of atoms (although there no doubt ar details about atoms, stars, and radiation that we don’t yet know).  On the other hand, some of the stuff we discussed later in class–for example the details about neutron star and black hole interiors and formation mechanisms and the stuff about dark matter distributions–has much less conclusive evidence behind it and cannot be regarded as being nearly so certain.  In fact, I strongly suspect that some of what I told you on those subjects will be revised in the next few years.  This means first that it’s neither crazy nor antiscientific to be skeptical about novel claims scientists make to the press, although it may be foolish to dismiss them out of hand.  Scientific knowledge at the frontier is often revised as better data and theories come along.  It also means that it would be wrong for you to take this process of revision to mean that everything science has discovered is equally up for grabs.  There are many things that we’re very sure of.
  • The scientific method is extremely powerful when applied to certain types of problems:  problems that involve the quantitative properties of observable phenomena.  Having gone through every step in the chain of observation and reasoning that grounds our understanding of main sequence stars, you can see that this understanding is well-motivated by the facts.  It is not something that scientists just made up and then imposed by social pressure.  Good science, where the scientific method is properly applied to a scientific problem, must be taken seriously.  It’s not simply one narrative among others that you can take or leave at will.
  • On the other hand, I think today the greater danger is the opposite, that people tend to treat the pronouncements of scientists as if they were oracles of Apollo or something, that what scientists say on any topic must be accepted without question.  There are a number of questions–questions about ethics, religion, metaphysics, history, and aesthetics–which are not amenable to the empirical scientific method.  This doesn’t mean that these aren’t good and meaningful questions; it doesn’t mean that we can’t find objective answers to them or that there aren’t rigorous intellectual disciplines for doing so; it just means that those disciplines are not those of the empirical sciences.  However, scientists have been given great prestige by society at large, and there is always the temptation for us to abuse that trust to promote our own opinions on issues where our expertise do not apply.  In this class, I’ve been very careful never to give away my opinions on anything outside my discipline, and that’s why.  So, how can you tell when a scientist is stepping over the line?  Most of all, by understanding how real science is done, you can have a good idea what sorts of problems it can properly be applied to.  Another rule of thumb is the following:  when somebody says “Science proves such-and-such” be on your guard.  Scientists presenting legitimate results are always more likely to say “such-and-such experiment proves…” or “such-and-such calculation leads us to expect…”  There’s no unitary “Science” that can bring the entirety of its authority to bear on any one question.

To close off, I’d like to say something about the past.  People sometimes act like the progress of science gives us reason to look down on our ancestors, who believed many things we now know to be false.  “How stupid they must have been to think the sun went around the Earth!”  For me, the lesson is the opposite:  the history of astronomy should fill us with humility and gratitude.  The ancients weren’t dumb–the sun really does look like it’s going around the Earth, and you’ve seen in our celestial sphere section how complicated that model ends up being and how well it captures what we see.   And yet it was wrong, as even greater geniuses were able to show.  How much of the stuff in this course could you have come up with on your own?  I know I’m not smart enough to have come up with any of it, or at best a very little.  Let us then be grateful that so much has been bequeathed to us, and that we now know so many marvelous things about the universe.

15 thoughts on “The science talk

  1. Bonald,
    I am looking for an elementary presentation of the the justification of the atomic hypothesis.
    Suppose a high-schooler asks, How do you know things are made u of atoms?
    How would you go on replying?

  2. I like that a lot. You might add a bullet “scientists are human” to point up the difference between scientists and science. Feynman tells that cute story about the measurement of the speed of light, you know the one? You could adapt it without too much trouble. That story illustrates one of the problems that arise from the fact that scientists are human and also the tendency of science to self correct. You could follow it up with another story he tells, the one about rats in mazes. That one illustrates that science does not necessarily self-correct (i.e. it’s a tendency, not a law), especially in the hands of people who don’t quite “get” what they are supposed to be doing.

    • Yeah, science doubles-down megalomaniacally as often as it self-corrects. Scientists aren’t just humans, they’re also creatures of the culture, and long for the approval that the culture and its perverted institutions offers to kept scientits.

  3. How to improve it: I think the last bullet point could use a few examples. Specifically, an example of where a scientist said “science says so-and-so” and was completely out of his depth (maybe Hawking’s musings on God?). And an example of a rigorous intellectual discipline for answering a question not the purview of science.

  4. You know what I think on this topic… but it might be worth hinting that the problem of dishonesty is – um -widespread; and a major task of any serious scientist is to locate the relatively-few specific scientists (from among the rotten mass) whose work he can trust (trust as being honest and competent, I mean – not trust as being true).

  5. I take it that your audience includes freshmen. If so, only a few will have been exposed to social-construction-of-science argument, or to the word “narrative” in this jargon sense. I would, therefore, explain the argument somewhat more fully, and present it as one they will likely encounter elsewhere in the university. Your students will have absorbed postmodern attitudes from popular culture, but very few will have any acquaintance with postmodern discourse.

    I think you might also exhibit some disciplinary pride and point out that astronomy is (along with physics) the gold standard of science, with a level of theoretical development and predictive power greater than every other science, and vastly greater than many so-called “sciences.” If we think of Science as a city, you’ve just shown your students the nicest neighborhood; you might mention that Science also has its Levittowns and slums.

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  8. Dear Bonald,

    If I was you, I would put in at least one lesson about the history of astronomy – The Sleepwalkers stuff i.e. disproving the whole myth of a very empirical, rational Galieli against the bigoted Church, how completely insensible Neoplatonism accidentally lead to good results etc. etc.

  9. Where do you teach that you are allowed to say that college is not for everyone? And do you have any new lines opening up?


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