Friday, September 13, 2013

Sean Carroll: "What Is Science?"

I've been meaning to comment on Sean Carroll's post from last July (July 3, 2013) but there always seems to be something else that commands my attention. The issue is important, in fact I've just finished an entire book on the question (Philosophy of Pseudoscience: Reconsidering the Demarcation Problem edited by M. Pigliucci and M. Boudry).

Sean Carroll (the physicist)1 has a view that's quite similar to my own. Read his post at: What Is Science?. Here are some key points.
Defining the concept of “science” is a notoriously tricky business. In particular, there is long-running debate over the demarcation problem, which asks where we should draw the line between science and non-science. I won’t be providing final any final answers to this question here. But I do believe that we can parcel out the difficulties into certain distinct classes, based on a simple scheme for describing how science works. Essentially, science consists of the following three-part process:
  1. Think of every possible way the world could be. Label each way an "hypothesis."
  2. Look at how the world actually is. Call what you see "data" (or "evidence").
  3. Where possible, choose the hypothesis that provides the best fit to the data.
The steps are not necessarily in chronological order; sometimes the data come first, sometimes it’s the hypotheses. This is basically what’s known as the hypothetico-deductive method, although I’m intentionally being more vague because I certainly don’t think this provides a final-answer definition of "science."
I usually define science as a way of knowing that based on evidence, rational thinking, and healthy skepticism. This is a broad definition, like Sean Carroll's.
Along these lines, you will sometimes hear claims such as these:
  • Science assumes naturalism, and therefore cannot speak about the supernatural.
  • Scientific theories must make realistically falsifiable predictions."
  • "Science must be based on experiments that are reproducible."
In each case, you can kind of see why one might like such a claim to be true — they would make our lives simpler in various ways. But each one of these is straightforwardly false.
Sean Carrol is correct and I'm pleased to note that most philosophers of science agree with him on the last two points. More and more of them have rejected methodological naturalism although there are still a few holdouts.
Some will object that this conception of science is too broad, and encompasses not only economics but also fields like history. To which I can only say, sure. I’ve never really thought there was an important distinction of underlying philosophy between what scientists do and what historians do; it’s all sifting through possibilities on the basis of empirical evidence.
That's another way of saying that he doesn't accept the narrow definition of science that restricts it to physics, chemistry, biology, geology etc. I agree.
Sometimes the fact that science is not the only kind of respectable intellectual endeavor gets packaged as the statement that there are other "ways of knowing." This is an unhelpful framing, since it could be true or false depending on unstated assumptions held by the speaker. Yes, mathematics is a different way of gaining true knowledge than science is, so at that minimal level there are different valid ways of knowing. But they are not merely different methods of getting at the truth, they are ways of getting at different kinds of truth. What makes science (broadly construed as empirical investigation) special is that it is the unique way of learning about the contingent truths that separate our actual world from all the other worlds we might have imagined. We’re not going to get there through meditation, revelation, or a priori philosophizing. Only by doing the hard work of developing theories and comparing them to data. The payoff is worth it.
I prefer to avoid the issue of whether mathematics is another valid way of knowing. To me it just seems like a tool that we use to collect data. But, aside from mathematics, I don't think there are any other ways of knowing that have a proven track record of finding real truths. I asked repeatedly for examples but the only ones people come up with are trivial things that don't even come close to qualifying as real knowledge in the epistemological sense.

Sean discuses two of these "truths" ("killing babies is wrong," "Justin Bieber sucks") in his post. One of them may be a bad example because Justin Bieber is a Canadian (Stratford, Ontario) and it is probably a universal truth that Canadians don't suck.

1. The other Sean Carroll, the biologist, is giving a public lecture at The Toronto Science Festival in Convocation Hall on the University of Toronto campus, on September 27, 2013.


  1. My intuitions (based on some experience) about math are:

    1) Math is thinking; thinking is math. That is, if you have several errands to do and decide what order to do them in, you are doing math. (You may not be doing it well.)

    2) Mathematical research can and does make use of empirical observations as well as reason (so it is not different in kind from other forms of scientific research, just different in degree - the degree to which it relies on observation). For example, it seems clear to me that the concept of integer numbers and their addition and subtraction is empirically based - if I have five goats and sell two of them, I observe that I always have three left. (There is a more sophisticated and recent example - an empirical observation which was the basis for Andrew Wiles' proof of Fermat's Last Theorem.)

    So I reject the premise that math is "a different way of knowing" than science.

  2. I think Carroll's three points were terrible for someone claiming there is a thing called science.
    This list would make every driver a scientist!!

    Science must be a higher order of intellectual human thought in reaching conclusions.. (I don't like ...ways of knowing...) Conclusions hits the point.

    That science must STILL be decided as to what it is shows its not anything.
    There is no such thing as science.
    Its just people thinking about things and using evidences to back up conclusions.
    The caste called scientists TRY to say their conclusions use better standards of evidence. so better confident in their conclusions. so a special word is used.

    if any investigation into truth ignores the supernatural then its already dismissed options for evidence and already is a lower standard of investigation!
    Any stopping of any species of options or evidence is nullifying any claim to a greater standard of evidence control before conclusions made.

    It really is just ones standards for evidence before conclusions are drawn.
    Repeatable experiments and so on are just saying this in another way.
    science means historically a high standard of evidence and then a high confidence in its conclusions.
    Origin subjects never used this high standard and so are easily attacked where it bothers us creationists.
    my point always to evolutionists is to state their top three biological scientific evidence for evolution in its great claims.
    I have never seen them do it.
    Evolution is not a scientific theory but only a hypothesis with secondary evidences claimed to be backing it up.
    Past and gone events are impossible to repeat or test.

    1. Robert, I hope to god that you are not a driver, but if you are, I hope that I am never forced to "share" the road with you.

  3. This phrase "it’s all sifting through possibilities on the basis of empirical evidence." is a good one.

    At least at the colloquial level, Science, History, etc., and the act of deciding whether it is safe to cross a road are all the same activities.

    Robert should understand that when he decides to cross a road, he does the same sort of things scientists do in the laboratory every day.

    He realizes there are at least two main hypotheses: it is safe or unsafe to cross road. He collects data using his eyes (his electromagnetic radiation detectors) and he repeats this data collection exercise at least twice. The results, if they are consistent, may favour one hypothesis over the other.

    He also collects data using a completely different mechanism based on the motion of air molecules (with his ears). Confidence in one hypothesis over the other is increased if the data from both sources agree with one another. There are several other data collection mechanisms distinct from either direct sight or hearing of cars coming down the road that will provide data supporting one hypothesis over the other.

    Once he has enough confidence in one hypothesis (it is safe to cross the road) he acts upon it. But he knows this is not inalterable truth, so he will continue to collect data as he crosses road noting any that seem to contradict the favoured hypothesis.

    There might be less (often politically motivated) distrust of science if non-scientists realized they do the same thing everyday and that drawing rational evidence-based conclusions about the nature of things is not a murky, suspicious activity performed only by egg-headed elites in ivory towers.

  4. The claims in the second box can be editied to give essentially correct statements:

    1. Science assumes that the world is real and cannot speak to the qualities of the purely imaginary.
    2. Scientific theories must be in principle falsifiable.
    3. Science must be based on evidence that is verifiable.

    1. Science assumes that the world is real and cannot speak to the qualities of the purely imaginary.

      I don't think that is strictly the case. The universe as we perceive it could be an elaborate simulation created by God for his amusement, that he controls do so as to appear to operate according to regular natural laws. Once could assume this to be true, and still use science to determine what "laws" God is using in the simulation.

      The issue of what is "real" is something for the metaphysicists to worry about. And when they finally come up with a way to figure that out, they can tell the world. In the meantime, scientists can just simply continue to ignore such seemingly unanswerable questions and get on with their work.