School leaders have two obsessions: potential, and why your students are not achieving theirs. The most important thing about potential is that it is a lie. Young people will never achieve their potential, because by telling them that they have it - and that it can be measured in grades - we destroy any hope that they had. The whole concept is a myth. The students we teach have no potential: they will achieve only what they work for.

We are often given lists of students with more “potential” than others and we look upon them as special. What we forget is that they are on these lists only because, in all probability, they have a small genetic mutation that allows them to think in a way that is slightly different from other students their age.

This does not mean they will succeed; this does not mean they are destined for greatness. The only factor that determines whether or not they will achieve anything is the amount of effort they put in.

Sadly, our schools cannot help students enough. Let me explain in simple terms: a school is a big box where children go in and adults, hopefully, come out. During the maturation period, the children are showered with knowledge in the hope that some of it will stick. The deciding factor for its absorption is, fundamentally, how porous the children choose to make themselves. Some are sponges, some are pebbles.

Unfortunately, the world outside the learning box is an ugly and pessimistic place. It expects nothing more of these new adults than that they wait behind the counter, desk or forecourt of another fetid, dead-end job as they pale into insignificance waiting to have children or die, or to have children and die.

This means, perversely, that these young people are totally free. They are free to do exactly what they want, and therefore they are wonderfully free to fail.

The most important thing that students can be taught is to embrace failure. Let’s teach them to walk hand in hand with defeat into the darkness. Teach them that if a man keeps fishing with the same equipment, he will keep catching the same fish. If he does not catch a fish, he should build a new rod. Or he should work hard to get a better job so he can pay someone to fish for him.

This is not a new idea but it is often forgotten: we assume that bestowing the badge of “gifted and talented” on a child means they will instantly become prime minister material. But what the badge does not do is give a sense of what success is and how to get it.

A really exceptional student will bother to hunt out things that they find difficult because they enjoy the pursuit of knowledge. They see success not as something that can be achieved, but a continuing journey. A mission. Students need to understand that success is not a moment. It is not a letter on a piece of paper, or a pay packet, or a brand new television. Tell them the truth: success is a lifetime.

If you want to distil success into a single moment then it is the last living moment. It is the smile on your face as you lie in your hospital bed at the end, surrounded by your loved ones. Success is in that moment when you look back and see all the things you did, and all that you tried to do. You do not even need to congratulate yourself, because you know.

We don’t encourage young people to go out into the world and find out about things that they, not we, find interesting. When was the last time you were taught something by a student? We are afraid of our subject knowledge being challenged, but we are fallible. We are not perfect. We should know this and allow ourselves to be educated by our students. It does not matter what they are interested in or what they teach you. It just matters that they are exploring something; it matters that they care. So encourage them. When you ask them to teach you, they might not be able to. But as with all tasks that fail in the first instance, that defeat is more important than any success.

Shun targets. Tell your students to think about what it is they care about. Tell them to go and be masters of their own futures. To follow their interests. To find things to pursue, fail at and eventually succeed at. Do not tell them that they are potentially C-grade students. Tell them that it doesn’t matter if they are not able to do it now, or do not understand it yet. Tell them off if they find something easy. Get them to go out and find something that they cannot do instead.

Because it is not “I can’t do this”. It is never “I can’t do this”. It is always “I can’t do this yet”.

Calum Mittie is a pseudonym. He blogs at calamityteacher.blogspot.co.uk