If Richard Dawkins had been smacked around the head with the double-slit experiment at an age when his skull was soft enough for him to feel the pain, he wouldn't be suffused with such luminous certainty about how the world works.

Evolution, the fundamental theory of biology, is tough for some folk to swallow. But that’s because a bunch of old bearded guys wrote something different a long time ago – and because the intuitions of an animal that lives for 70 years can’t handle what complex systems can get up to in 4.5 billion.

But unlike quantum theory, evolution has nothing mind-warpingly weird about it. So the nature of the real world seems obvious to an evolutionary biologist.

We physicists know from bitter experience that it isn’t obvious at all, and there are quite a few prominent physicists who believe in something beyond the material world. John Polkinghorne is an Anglican. Jocelyn Bell-Burnell is a Quaker. Stanley Jaki is a Benedictine priest …

So when a young theoretical physicist starts claiming that something spiritual is “obviously nonsense”, as Bee has been doing over at Cosmic Variance, I start getting uncomfortable.

Referring to research done at the Maharishi University of Management, she says they give their theories an “appearance of similarity to established theories” by writing down “fancy Lagrangians”. Then she goes on: “Though to us this is obviously nonsense…”

And I start to wonder. Who is this “us"? And how obvious is it?

Nonsense it may be, but obvious nonsense is not the same thing as nonsense. Even in mathematics what is obvious is not always apparent – as the GH Hardy story demonstrates.

When it comes to the real world, a sure way to go broke is by betting on the truth of statements that seem obvious.

Like most physicists I first realised the world was far from obvious when they battered me with quantum mechanics at university. It took months of wrestling with Einstein, Rosen and Podolsky before I realised I didn’t need to make sense of this stuff, just use it to solve problems.

I could do that whether my brain was an array of particles, a superposition of waves, or a bit of both depending on what I was using to look at it at the time. Figuring out what it all meant, if anything, could come later.

Of course later never came, not for me and not for many another physicist – Neils Bohr and David Deutsch being obvious exceptions.

If the science of transcendental meditation were “obviously nonsense”, it would hardly merit 20,000 words of fascinating discussion from guys who are just as capable as Bee of stringing together rational thought. Would it?

Well maybe it would. Generating the appearance of dispute is what the tobacco companies, the climate change deniers and the intelligent designers do best – even using the same PR consultants sometimes to sow their seeds of confusion. But this looks different to me.

It wasn't however what started me thinking about what is obvious and what is nonsense. That was something much simpler - or apparently so.

A couple of weeks ago scientists at Queen’s University, Belfast announced the first discovery of the YORP effect in the solar system. In trying to figure out the science for a website of school teaching resources, I began thinking about Crookes' Radiometer, in which the properties of photons also have surprisingly macroscopic effects.

This radiometer is a little physics toy made of four small silver and black blades mounted on a pivot inside an evacuated glass chamber. I had first come across it at university but, unlike quantum mechanics, the science seemed obvious to me.

It was only when I was looking into it again, for instructive parallels with the physics of YORP - there aren't many - that I discovered that my “obvious explanation” was nonsense.

But I'm not alone. The explanation in Encyclopaedia Britannica is also nonsense. In fact more nonsense has been talked by competent scientists about Crookes' radiometer than about transcendental meditation.

The science seemed obvious to them, as it did to me, so they didn’t bother doing the hard sums.

Two physicists who didn’t make that mistake were Einstein and Maxwell, both of whom explored the dynamics of the little system in considerable detail. (No doubt Newton would also have done so, if he hadn’t been dead at the time.)

Science is a balancing act between creativity and analysis, between openness to new ideas and rejection of “obvious nonsense”. I visited a school this week where the headteacher was trying to foster creativity in every subject. A science teacher wasn't having any:

“We try to get the creativity out of the kids by teaching them the scientific method.”

That teacher had lost his balance.

It’s very easy to do.