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Twenty-first century science

by Michael Nielsen on March 29, 2005

Dave Bacon writes:

One often hears biologists say that biology is the “physics of the 21st century.” When they say this, I think the main motive is to indicate that great scientific advances will be coming out of biology in the next century.

I’ve never actually heard a biologist say this, perhaps because I know relatively few biologists. I have heard several physicists say it, presumably that class of physicist who wishes they went into molecular biology, or perhaps made billions in the .com boom.

My own opinion is the physics is going to be the physics of the twenty-first century.

I have two broad sets of reasons. First, there are a bundle of really important fundamental questions that we don’t know the answer to:

  • How can quantum mechanics and gravity be put into a single theory, preferably one integrating the usual standard model of particle physics?
  • What’s up with quantum mechanics and measurement? The fact that we don’t properly understand our most successful scientific theory always seems to me like something of an embarrassment.
  • How did our Universe start? How will it end? What is its structure?
  • There are many other puzzles – dark matter, the cosmological constant, the Pioneer anomaly, and others – which we don’t understand. It’s possible and maybe even probable that some of these are unimportant. Still, it seems pretty likely that one or more of these is the tip of a really big iceberg.

Progress on any of these is likely to come from within physics; it will certainly affect physics, and if past history is any guide, it will probably profoundly affect the rest of science and technology as well. Of course, it may take decades to make real progress on these problems, and I suspect this is where some of the attitude Dave refers to comes from – a feeling that the grass is greener on the biological side.

My second set of reasons are more applied, although I suspect they will greatly impact the fundamental questions as well:

  • Nanotech. Yes, there’s lots of hype. My guess is that in the short run, this will turn out to have been over-the-top, but in the long run, it’ll seem incredibly restrained. A self-replicating assembler, even one with extremely limited capabilities, is likely to have astonishing consequences.
  • Complex quantum systems. I think we’ll see a revolution as people assimilate the idea that whole new types of complexity can arise in quantum systems, going entirely beyond what is possible in conventional classical systems. My guess is that phenomena like superconductivity and the fractional quantum Hall effect are the tip of the iceberg.
  • Quantum nanoscience and quantum information. These are really two sides of the same coin: leveraging the power of complex quantum systems to accomplish tasks (either material tasks, or information processing) impossible or impractical in the classical world.

I could, of course, easily be wrong about any of these things, and there’s undoubtedly a lot that I’m missing. But these are all reasons why I’m very optimistic about the role physics will play in twenty-first century science.

From → General

  1. Another reason I think biologists say they will be the next century’s physics is that they are collecting an unbelievable amount of data which has no good theoretical basis. Sort of like seeing the particle explosion in physics where there was no idea how to explain what was going on, but lots of robust data. Of course the “biology problem” is much more complex, but the search for universals among these mounds of data really does remind me of the 60s and 70s.

    And it’s also true that while physicists who say biology will be the next physics are often jealous of the field, I think biologists who say it are also playing the “physics envy” card. Quite a success, that 20th century physics, no?

  2. Rodney Polkinghorne permalink

    Biology won’t be the physics of the 21st century, but the study of self-replicating assemblers and complex systems will be? I must be missing something.

  3. Rodney: I’m not sure what you’re saying. I can think of at least two completely different interpretations of your remarks.

  4. agm permalink

    Mr. Polkinghorne refers to one of the main gee-whiz goals of the nanotech field. It may or may not be a pipe dream, but it will be heavily influenced by the strong push into nanoscale systems and the convergence of that work with biological systems. My money is on when nano people and biophysicists start really talking to each other, or when biologists start learning some serious physics, neither of which am I aware of happening to a great extent just yet.

  5. agm permalink

    Oh, and pretty…

  6. agm: That was one of my two interpretations of Rodney’s post. Over the short-run (next 20 years) I agree that bio and nano are likely to be strongly interlinked. Over the long run, though, I think humanity’s nanotech will be a great deal better than “biological nanotech”, and the two fields will only incidentally be related, mostly at the level of applications.

    My other interpretation of his post was that it was a skeptical remark about the feasability of nanotech.

  7. Rodney Polkinghorne permalink

    The point I was trying to make is that biologists study self-replicating
    machines (which they call life), the methods by which they do so are
    quite different from those we use to study physics, and I don’t see
    any reason to think ours would work better. If we start producing
    complicated nanosystems, I think the way we reason about them will be
    more like biology than physics.

    Unlike Michael, I’m not convinced that design can do a better job than
    evolution in this context. I suspect it’s similar to the planned vs
    market economy thing, in that the environment is so complex that any
    planner is bound to neglect something big. You would think that having
    your nanomachines produce oxygen as a byproduct was a trivial issue,
    wouldn’t you?

  8. For one example where current nanoengineering is a lot better than biology (and which is based on physics), consider the modern semiconductor industry. I expect we’ll see a lot more examples like this.

    I also think that the market versus planned economy analogy is flawed, because economic circumstances are always changing. Nanomachines present a design problem, where you can simply accumulate improvements in the design. You’d be very surprised if this year’s DVD players were worse than last year’s, yet this year’s budget could easily be worse than last year’s, because improvements are not cumulative in the same way.

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