The worlds of science and medicine are packed with rules and laws.

Don’t worry. I’m not expecting you to remember all of them, or even be ready to explain Heisenberg’s uncertainty principle.

I am certain that I know absolutely zero about theoretical uncertainty principles in science, though – like all GPs – I know plenty about uncertainty in medicine.

Indeed, when it comes to medicine, the laws have fascinating relevance. For years we have been told about various 80/20 rules.

It seems that 20% of patients in any healthcare system account for 80% of the cost. In general practice 20% of our patients generate 80% of our work.

Julian Tudor Hart’s inverse care law sadly remains every bit as relevant today as it did when he first wrote about it back in 1971.

It states that the availability of good medical care tends to vary inversely with the need for it in the population served. 

However, the inverse care law is far from being the only medical law. A few years ago, Siddhartha Mukherjee, the author of the brilliant book on cancer The Emperor of All Maladies, wrote a short book describing three laws of medicine that all of us can identify with.

My favourite was ‘strong intuition is much more powerful than a weak test’ – something that every GP will recognise.

Indeed, our lives in general practice are absolutely littered with laws. Every GP knows that the nicest patients tend to have the worst illnesses.

We are all aware that there is an inverse law of complaints – those who complain the most will typically be the patients that you did the most for, while the ones who should complain almost certainly won’t.

We all know that when doing a home visit to a sick child, you will inevitably kneel on the wet patch by the sofa.

It’s not just medicine that is ruled by these laws. Everyone knows the queuing law that says that ‘the other queue always moves faster,’ and the driving law that says that wherever you want to go will be on the edge of the map – one law that modern technology, in the form of sat nav, may finally see off.

You’ve probably got your own favourite medical laws that you live by, but mine would include:

• Never arrange an investigation if you don’t know what you will do with the answer

• The most complex problem you see all week will be the final patient to attend on a Friday evening

• The effectiveness of a treatment for a disease is inversely proportional to the number of therapies available to treat it

• If the treatment you have given hasn’t worked, consider the likelihood that you’ve got the diagnosis wrong

If your career has got you involved in any sort of management, whether on a practice or a locality basis, you will have become aware of the law of committees that states that 'any simple problem can be made insoluble if enough meetings are held to discuss it'.

Of course, nothing can ever beat the truest law of all – Parkinson’s law – that states so simply, ‘work expands so as to fill the time available for its completion.’

If only it contracted in the same way, so that when time is short, there is less to do.