Modern Physics and Scientific Thinking

Yesterday’s big post on why I think people should embrace scientific thinking in a more conscious way than they do already (because my claim is that most people already use scientific thinking, they’re just not aware that they’re doing it) is clearly a kind of explanation of the reason behind my next book, but what about the previous two? How does teaching people about modern physics through imaginary conversations with my dog serve the general goal of getting people to think more scientifically?

The following is a bit of a retcon– after all, the proximate cause of my writing those books was that an agent contacted me and suggested I could get paid to write such a book. And the proximate cause of that was the fact that I think modern physics is the coolest thing ever, and would happily write about it just on the basis of general enthusiasm for the subject.

There are a couple of reasons, though, why I think modern physics is particularly useful for teaching people about the power of scientific thinking, in the sense of yesterday’s post. That might seem counter-intuitive, because modern physics is, well, counter-intuitive. Relativity and quantum mechanics are famously weird and surprising, which is why talking to the dog about them is helpful in the first place. Given that, then, how can I claim that these are a particularly good introduction to scientific thinking in general?

For one thing, physics is exceptionally clean and uncomplicated. It’s highly mathematical, sure, but the effects that we measure are usually completely unambiguous. Yeah, the idea that material objects like electrons behave as waves is strange. But if you want proof of it, just look at the “Featured Image” at the top of this post, taken from this new paper on double-slit diffraction (freely available in the open-access New Journal of Physics). There’s really no question that those electrons are producing an interference pattern, exactly as quantum mechanics predicts. The experiment is simple enough, and the results are visually very striking, in a way that doesn’t require complex analysis to be convincing.

There’s also a level of certainty and robustness to a lot of physics results that is unmatched in other sciences. Every couple of weeks there’s another flurry of posts in the life-science blogosphere about results that were statistically significant at the 0.05 level turning out to be false positives. This is one of the reasons particle physicists tend to look down on those stamp collecting biomedical types– the threshold for claiming a new result in particle physics is several orders of magnitude greater, a degree of statistical certainty that you’ll never match in any trial with a finite number of human subjects. Even relatively recent discoveries in physics are solid in a way that most other sciences can’t hope to match.

The other factor that makes modern physics well suited to demonstrating the power of scientific thinking is the very fact that it is so weird and esoteric. We’re talking about single systems at incredibly tiny scales– the nucleus of an atom is roughly 0.000000000000001m across, and quarks and electrons are many times smaller than that. And yet, we have a very good handle on how physics works at those scales, thanks to the power of scientific thinking. You need to be really clever to get information about these systems out, but it can be done by thinking carefully about what our models of the universe predict in different circumstances, and checking those predictions against experimental data.

When we do that, we have to invoke some awfully weird stuff– material objects behaving like waves, virtual particles popping out of nothing and behaving in strange ways, non-local correlations between pieces of an entangled quantum system. None of this is stuff that you would immediately guess, but all of it is absolutely and incontrovertibly real, as demonstrated by the clear and unambiguous results of any number of experiments. We can use quantum electrodynamics, with all its bizarre elements, to predict certain quantities to 14 decimal places, and those predictions agree perfectly with the experimental measurements.

This is one of the things I tried to emphasize in the books: all of this stuff is true, and grounded in experiment. Electrons are unquestionably waves– we’ve got the pictures. EPR-type entanglement is absolutely real, and defies classical common sense– we’ve seen this with photons and even atoms. Motion and gravity make clocks run slow– we have the measurements to prove it. There are clear and unambiguous experimental demonstration of all the weird aspects of modern physics.

So, in those respects, as strange as it may seem, modern physics is a fantastic way to demonstrate the power of scientific thinking. If we can use the look-think-test-tell procedure to unambiguously demonstrate the validity of something like QED, there’s no reason why it can’t be applied to more readily accessible systems on everyday scales.