Almost every scientific explanation that I read about how memory works seems to me like benign guesswork.

The explanations use our current understanding of anatomy and physiology which will one day be seen to be as simplistic as the descriptions of the vascular system before Harvey’s discovery of the circulation.

That’s nobody’s fault. We only know what we know, and one day we will know much more, but it still leaves me massively mystified by so many aspects of our use of memory.

For instance, why is it that an aroma can instantly take you back to a time and place that you may not have thought about for decades?

Some time ago I was doing some DIY, and while drilling a piece of timber the warm smell that wafted as the bit turned in the wood instantly took me back to the age of six, watching my dad doing carpentry in his workshop.

I hadn’t thought about that workshop for more than 50 years. I couldn’t have begun to describe it to you, but the olfactory trigger from my drilling instantly brought everything back, the cobwebs in the corner, and the tobacco tins full of screws.

Those memories must have been sitting in some unused corner of my brain, just waiting for the right trigger. It’s fascinating, and it’s a total puzzle.

Why do certain patients, or certain consultations, stay with you when countless others fade away? Sometimes it may simply be because they are so unusual.

I will never forget a patient, now long dead, who consulted me with a painful distressing condition that I had never heard of.

A few minutes searching and I discovered that there had only ever been seven cases of this particular syndrome ever reported in the medical literature. It’s little wonder that I’ve never forgotten her.

What about those bizarre moments when you are struggling to reach a diagnosis and a metaphorical bell rings in some distant corner of your brain to flag up a new diagnostic possibility?

I had many occasions when my attempt at reaching a differential diagnosis unexpectedly triggered memories of a condition that a few minutes earlier I would have completely denied any knowledge of. It’s almost certainly happened to you too.

Why is it that you can always remember the name of some of your patients, and inevitably forget others? There’s something particularly challenging about being consulted by a patient whom you may have known for several years and yet about whom you can remember absolutely nothing. This is a particular risk if the computer is down, and no records are accessible.

Equally strangely, why is it that being able to glance at even just a few words on a summary record can be enough to trigger a detailed memory?

You read a couple of words – maybe diabetes, divorce – and are instantly able to recall the complexity of all the previous consultations.

Indeed, if I could have my life as a GP all over again, and could be granted just one additional skill, it would be a much better ability to link faces and names.

Living and working in a small community, I lost count of the times I would meet someone in the street, and have an entirely unproductive discussion, simply because I hadn’t the least clue who they were. It was even worse when they wanted to tell me about their grandmother or some other relative, and I had no possible useful response.

Or that might just be how I remember it. Who knows?