Too much is ill, mis or uninformed, and often from people who ought to know better. There’s a rush to present simplified answers, to try to clear everything up with a couple of soundbites and a nod to popular opinion.

But it’s not simple.

People say 'oh, it’s not rocket science'. As these things go, rocket science is actually a comparatively simple bunch of equations. Rocket engineering on the other hand, now that’s difficult. Any 6th form physics student can (or at least, should be able to) do the theoretical calculations on how much fuel you need to get a given payload to escape velocity. But actually designing the pumps, tanks & nozzles to get the stuff to burn, let alone actually building them (hands up anyone with the knowledge of metallurgy to understand precisely which alloys you should be using where?) is a different matter, and only the most gifted and dedicated of amateurs have even a hope of getting a rocket to actually work (and even then they’d be the first to admit their debt to the professionals who build the parts).

Tax is much the same. Should everyone pay a fair amount of tax? Well that’s so trite it barely even deserves to be a question.

What is a fair amount of tax? You might as well ask what’s the right shade of blue, or how tall should a politician be.

Laws are the next best proxy we have to fairness when it comes to tax. But then the laws are (to put it mildly) complicated. And Professor Brian Cox can point to planetary movements, reel off the equations, and explain what’s happened. When someone asks why a baseball pitch doesn’t work the same way, that’s easy – baseballs are operating in an atmosphere, and under another heavy gravitational field. And there’s no real mileage in trying to establish the physics of what would happen to a baseball in space, or a planet in the earth’s atmosphere and gravity, because the two scenarios are implausible. And there’s no need to worry about how a watermelon would operate at high altitude, or a whale sized object on the edge of the atmosphere, because such things don’t exist. There is no gentle graded curve between the tiny everyday objects that we all handle and work with and the vast numbers and forces which operate in astronomical models. There’s a clear break between them; no need for complex transitional calculations.

But tax isn’t like that. There’s no legal difference between the structure your window cleaner can set up to run his business and the one that a multinational might use to handle its international treasury function. There’s no difference in principle between the calculations that a business handling nuclear waste reprocessing does to work out its tax liability and those that a corner shop might do. And the tax system isn’t just trying to run one set of equations at once; it’s got two or three sets to cope with (companies, partnerships, limited vs unlimited liability variants, sole traders – they’re all valid forms of business, and it’s open to business to mix and match the legal forms to get itself the best result.) So it’s a bit like having planets that can behave like baseballs if they want to.

And the best bit is that the tax system isn’t like physics, which gets done to us and we just have to try to work it out from the evidence. The international tax system is something we’ve done to ourselves (albeit perhaps indirectly, in that it’s actually the work of elected politicians).

Now, I have to say that if we were in a position to be able to revise the equations that govern the temperature that the sun burns at, or the force exerted by gravity, I’d probably advise caution in the choice of those writing the new rules. I’d certainly want them to have a pretty firm grasp of astrophysics; a background in marketing or even an advanced degree in economics just wouldn’t quite be what I was hoping for.

But when it comes to the tax rules, there is a nasty tendency for the value of knowledge and experience to be ignored. I’m sure it would be terribly helpful to have the sun coming out at night instead, when the light would be more useful. Clearly weakening the force of gravity would make us all lighter and put diet clubs out of business overnight. Spinning the plant’s axis of rotation through 90 degrees would put London in the tropics and make for much warner winters; bound to be a good thing.

It’s fairly obvious that actually none of those would be terribly good ideas, and no half-sane scientist would ever fall for them. But of course that’s another advantage the physicists have; they can be reasonably certain that their system works and they’re not at serious risk of breaking it. Tax systems aren’t like that. The British one was described this week as “complex, confused, irrational, punitive and in urgent need of root and branch reform”. And that got it a rating of 21st out of 34; quite what they’d have to say about the US system (33) or the French (34) is anybody’s guess. And yet unsound proposals get put forward for tax all the time in the comments columns of the internet, and explaining why they won’t work can require a degree of engagement and willingness to learn that all too few seem prepared to put in. I’d love to help more people understand the basics of tax system design, it’s really important stuff. I’ve tried to do some of it in my report Simplicity in tax.

But please, don’t ask me to condense 746 pages of BEPS documentation into 140 characters. It’d be about as much use as posting  and if you know what that means, you don’t need me to explain it.

(It’s the Tsiolkivsky Rocket equation, for which I must thank Randall Munroe, of XKCD)

*This post was originally written in 2014 and as well as understating the difficulty of what Professor Brian Cox does, predates the OECD BEPS project and Covid-19.