David Deutsch on Explanations

Physicist David Deutsch explains explanations.

There are tons of gems in here, so watch it for yourself. When I discovered the video, I realized it fit well with my previous post.

  • Deutsch view of what makes something “science” challenges the normal way people think of it. He, in my opinion, is correct that science is not directly related to prediction, empiricism, testability, or induction. He doesn’t cover the myth that science is based on the ability to falsify things, but that should be added to the list.  Note: pay attention to the word “direct” here.
  • What do you think of the idea of explanations being better or worse based on ease to vary them? (I am still trying to mull that one other.)
  • What do you think of his view about all problems having solutions?
  • I loved his examples of “a wizard did it.”
  • In this view, what is the proper relationship between science and theology?
  • Can the rule of “easy to vary” being a “bad explanation” apply to theology? Can we tell good from bad theology that way?

23 thoughts on “David Deutsch on Explanations

  1. Fascinating.

    I think I quite like this notion of ease-of-variation. I think one ramification of this principle is that hard-to-vary explanations are hard to find, simply because (as Deutch said) “every detail plays a functional role,” so one cannot expect to accidentally get one of the details right. But once one detail is found, the entire explanation emerges.

    Do you think that was a reference to global warming? If so it was masterfully subtle.

    On hard-to-vary explanations in theology: they may be rare, because for every gospel principle which I hold to be true I’ve met an LDS person online who has a different twist on it.

  2. Interesting talk.

    So basically he is saying it is not enough for a theory to be falsifiable, but that it needs to have a very small parameter space? (Hard to vary). Though I agree, I will ask if having a large parameter space (easy to vary) is equivalent to saying the theory isn’t very falsifiable?

    I guess I am wondering if fundamentally what is important is that a theory is falsifiable and that the size of the parameter space is somehow a measure of “how falsifiable” a theory actually is.

    This is the common critique of something like string theory. Technically it is falsifiable, but the parameter space is so large that people wonder if it can actually be falsified.

    Nevertheless, I was very interested when he said (paraphrasing) “How do we know spacetime is curved? Because we see this dot during an eclipse here rather then there… how do we know about parallel universe? Again dots.” (See 7:49 on video.)

    What!!! *I want to see these dots that help us know parallel universes exist.* 🙂

  3. “Do you think that was a reference to global warming? If so it was masterfully subtle.”

    Um… I think maybe I watched two videos by David and he mentioned global warming in the other one. *sheepish grin*

  4. Joseph,

    Deutsch believes the dots and patterns of light interference are the evidence the existence of parallel universes (MWI style).

  5. Joe,

    I do not personally believe that science is really based on falsifiability per se. I think there are things in science that are accepted theories that may never be falsifiable (a point Penrose made in one of his books).

    Popper is often credited with the whole “science is only that which can be falsified. However, he didn’t actually say this. I’ll have to find the quote.

    “On hard-to-vary explanations in theology: they may be rare, because for every gospel principle which I hold to be true I’ve met an LDS person online who has a different twist on it.”

    This is something I’ve noticed too. This suggests that theology is either of a different kind than science, or it is “vague science” at best. I think maybe both of those are true. Theology is about making sense of things that science can’t yet touch (though may some day, probably after the second coming). The end result is that there needs to be huge latitude in how it’s interpreted.

  6. Yeah, I didn’t see the global warming reference there, but I’d like to see it. Perhaps the next post?

    If I may add a thought as a non-scientist, I think science gets in trouble when it makes wild conjectures based on limited information (ie, global warming but even macroevolution) and describes the science as “settled.” Karl Popper has shown as well as anybody that science is never settled — new information always comes in. If scientists would stick to provable, “hard to vary” results and then say, “we can make a conjecture” in one direction or another but clearly describe these conjectures as unsettled science, they would be much less controversial and much more respected.

    I think that is one thing Deutsch is getting at, which is why he quotes Popper.

  7. “All scientific theories are conjectures, even those that have successfully passed many severe and varied tests.”

    –Karl Popper

  8. Geoff,

    I’ll do a future post on global warming. As I once mentioned, I am in favor of taking action against the effects of CO2 emissions. I think Popper’s view on “settled science” not existing is precisely why we need to act. Specifically, given that all science is conjecture and never settled, it’s hard to see why the cry of “there is no proof” is meaningful. There will never be proof because it’s impossible to have proof. That being the case, we need a different bar on whether or not to act.

  9. Geoff, Bruce,

    I would love to see the global warming debate. I haven’t worried too much about it because conservation seems good and burning fossil fuels until they run out seems bad, but alarmist claims which result in policies disproportionately affecting the poor can’t be good either. I have no idea what to think on this one.

  10. I’ve had a lot of questions, since the measures most global warming advocates have put forth as “solutions” compared to the projections, meant catastrophic disaster in the near future.

    On the other hand, we’ve had a ten year spat of global cooling. Which appears to validate earlier global cooling warnings, while making a number of the scandals and other things make sense. If the predictions are fudged, then the solutions proposed aren’t hopeless half measures, deck chairs on the Titanic, sorts of things.

    But I have a lot of questions.

  11. Stephen,

    Great to hear from you again. It’s been a long time.

    I’ll try to include my own proposal on how to deal with CO2 emissions and global warming (those aren’t the same problem, just realted probelms.)

    But as of now, the only sane voice in this debate has really been the authors of Super Freakonomics, who suggested pursuing immedate fixes rather than only trying to cut CO2 emissions. This gets around the “deck chairs on the Titanic” problem and has the further advantage of working even if global warming turns out to be not man made.

  12. Bruce, except the global-warming people have been proven to be liars and deceivers not only on the global-warming issue, but several of the related issues. Even the most “rightous” global warming bigots are guilty of selective presentation of data, as per John Stossel.

  13. Books, I’ll give you plenty of reason to argue. I’m going to probably do three or four posts on the subject.

    Do you have a link to the John Stossel story for me to review?

  14. Bruce, if you want to bring your “A” game to this debate, I would strongly encourage you to review a few web sites.


    The former is a highly respected science-oriented site that has explored every possible angle of the global warming debate (from the skeptics point of view). The latter is an aggregator of skeptic links on the global warming issue.

    I have read most of the pro-AGW sites. Probably the best one is http://www.realclimate.org.

    I have been following closely the global warming issue since the late 1980s, and I have literally hundreds of links saved. If I can make a suggestion, don’t make the mistake that many pro-AGW people make, which is to assume that skeptics are all idiots/haven’t seen the data/if only they would read the IPCC reports/if only they would read the Bush administration’s reports on global warming/don’t they know there is a consensus and the science in settled? Actually, most of us have read all of the pro-AGW reports and STILL have enough actual data and facts and scientific analysis to make some pretty strong arguments. Usually such discussions devolve into repeated claims that the science is settled, there is a consensus, etc, etc. That ain’t likely to fly when people have strong data showing the science isn’t settled and that the consensus was manufactured, at least partly for political reasons.

  15. Drat! That was going to be my *whole* post! I was going to put up a link to IPCC and the Bush adminstration’s reports and say “here, read for yourself and get educated your idiots!” 😛

    Now I’m going to have to abandon my whole plan! 😉

  16. Bruce, if I may add one more comment, it occurs to me that there is a LOT of similarity in the discussion between “warmists and deniers” and the discussion between anti-Mormons and Mormons. Here’s what I mean by that.

    A lot of anti-Mormons just kind of assume that everybody knows Joseph Smith was a gold-digging con artist who wrote the Book of Mormon in a spare weekend. So they will make the most juvenile arguments without ever actually reading a lot of the scholarship by Hugh Nibley, FARMS, FAIR, etc, and they don’t ever address the actual arguments made by Mormon scholars. Most discussions with anti-Mormons will inevitably end with, “well, everybody knows the Book of Mormon is made up.”

    Virtually all of the debates I’ve had with global warming promoters usually involves me providing a lot of facts and statistics and the global warming promoters providing links to the IPCC report and saying “everybody knows there is a consensus.”

    Glad to hear that won’t be your strategy. 🙂

  17. Book, if I may, I think Bruce is just being thorough and wants to make sure he addresses all of the arguments out there, so he was asking for that link so he could see what Stossel had to say.

  18. Books, Geoff is correct. I was just being friendly and making sure I knew the concerns of my audience up front.

  19. Pingback: » The Conservative Case for Taking Immediate Action on CO2 Emissions – Introduction The Millennial Star

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