What happens to your beliefs when information changes or prevailing views shift? Do you change your mind or do you accommodate it? Or do you stick with what you always thought – it was good enough then so it’s good enough now?

That’s the attitude a lot of people take, but it simply makes no sense. We know people generally dislike change, at least when they’re not in control of it. But look, the whole of scientific progress relies on modifying or even scrapping theories when new data comes along that overrides it. Newton’s theory of gravity was good enough until Einstein pointed out that it only went so far.

And it’s not just science this applies to. Take social attitudes. When I was young, western attitudes to race, sexuality, women were very different from what they are now. If everyone insisted on sticking with the prejudices they grew up with, things would change even more slowly than they do. And not because the idea everyone first thought of was unassailably right. The reason society’s outlook has changed is not only because the younger generation takes a more egalitarian view, but because many older people also adjusted their thinking as they went along. They were persuaded by the arguments they heard and the attitudes they witnessed and the people they met, and were broad-minded enough to recognise that their old ways of thinking were out of date. Shame even more of them didn’t join in.

Social attitudes change very gradually. And unless things are going at such a slow rate you hardly notice your ideas changing, most people tend not to change their minds once they’re set. I’m not just talking about long-term attitudes, but about supporting more immediate arguments. Once you’ve decided that you definitely need to move house, or launch this product line, or set up a local women’s football team, or become vegan, or drop your prices, it’s easy to fix that belief in your mind. You may have considered it closely when you were still deciding, but now you close off your thinking. It’s a done deal. Time to stop thinking, lock down your decision and get on with it.

Um … who said you have to stop thinking just because you’re doing? These kinds of ideas shouldn’t be set in stone. That makes no sense. If new information comes along, why wouldn’t you reconsider – and perhaps revise – your view? People used to think smoking was good for you, especially if your lungs were bad (which they very possibly were if you smoked). Then scientists produced new information to show that actually smoking was very unhealthy. Do you think existing smokers should have ignored this new information? Of course you don’t.

You decide to move house. Now suppose you take a big financial hit, or your adult son wants to move back in with you, or the housing market changes unexpectedly. It only makes sense to reconsider your decision. You might stick with it or you might not, but you need to be open to change. So never be sure of anything – or at least only until new information comes along. Then double-check whether your view is still valid.