We grow up – inevitably – with a strong attachment to a plan A, that is, an idea of how our lives will go and what we need to do to achieve our particular set of well-defined goals. For example, we'll do four years of law school, then move out west, buy a house and start a family. Or, we'll go to medical school for 7 years, then go to another country and train in our speciality of interest and hope to retire by 55. Or, we'll get married and raise two children with an emphasis on the outdoors and doing good in the world.

But then, for some of us and, at one level, all of us, life turns out to have made a few other plans. A sudden injury puts a certain career forever out of reach. We discover an infidelity or make a small but significant error which changes everything about how crucial other people view us.

And so, promptly, we find we have to give up on plan A altogether. The realisation can feel devastating. Sobbing or terrified, we wonder how things could have turned out this way. Who could have predicted that the lively and hopeful little boy or girl we once were would have to end up in such a forlorn and pitiful situation? We alternately weep and rage at the turn of events.

It is for such moments that we should, even when things appear calm and hopeful, consider one of life's most vital skills: that of developing a plan B.

The first element involves fully acknowledging that we are never cursed for having to make such a plan. Plan As simply don't work out all the time. No one gets through life with all their careful plan As intact. Something unexpected, shocking and abhorrent regularly comes along, not only to us, but to all human beings. We are simply too exposed to accident, too lacking in information, too frail in our capacities, to avoid some serious avalanches and traps.

The second point is to realise that we are eminently capable of developing very decent plan Bs. The reason why we often don't trust that we can is that children can't so easily – and childhood is where we have all, after all, come from and continue to be influenced by in ways it's hard to recognise. When children's plans go wrong, they can't do much in response: they have to stay at the same school, they can't divorce their parents, they can't move to another country or shift job. They're locked in and immobile.

But adults are not at all this way, a glorious fact which we need to keep refreshing in our minds and draw comfort from in anxious moments. We have enormous capacities to act and to adapt. One door may close, but there truly are many other entrances to try. We don't have only one way through this life, even if – at times – we cling very fervently to a picture of how everything should and must be.

We're a profoundly adaptable species. Perhaps we'll have to leave town forever, maybe we'll have to renounce an occupation we spent a decade nurturing, perhaps it will be impossible to remain with someone in whom we'd invested so much…. 

It can feel desperate – until we rediscover our latent plan B muscle. In reality, there would be a possibility to relocate, to find someone else, to navigate around the disastrous event. There was no one script written for us at our birth, and nor does there need to be only one going forward.

It helps, when flexing our plan B muscles, to acquaint ourselves with the lives of many others who had to throw away plan As and begin anew: the person who thought they'd be married forever, then suddenly wasn't – and coped; the person who was renowned for doing what they did, then had to start over in a dramatically different field – and found a way.

Amidst these stories, we're liable to discover a few people who will tell us, very sincerely, that their plan B ended up, eventually, superior to their plan A. They worked harder for it, they had to dig deeper to find it and it carried within it less vanity and fear.

Crucially, we don't need to know right now what our plan Bs might be. We don't need to ruminate on them all now or anticipate every frustration that might come our way; we should simply feel confident that, were the universe to command it, we would know how to find a very different path.