“At my last school,” says Sophie, “my best teacher was Mr Bromley.” Pause. “I liked him ‘cos he didn’t have favourites.”

Now Sophie can be quite cunning for a nine-year-old. Surely, I think, there’s no hidden message here? Not for good old me, my self-image brimming over with fairness and equal opps for all? “Yes,” I say, “it’s important for teachers to be fair. I don’t have favourites either. Or do you think I do?”

“Well, yes, actually,” says Sophie. A second, quieter child nods agreement, then a third.

I am taken aback. I don’t have favourites. Never have done, through principle. Have never wanted to. Find the idea abhorrent. “SoI who do you think I favour then?”

“Samantha. And Gregory.” No hesitation.

Samantha and Gregory are pupils who always do their best work, who are quiet and attentive. Samantha lines up sensibly, considers others and is kind to animals. It’s just the way she has been engineered by nature and nurture. Gregory has learning difficulties, which he is overcoming through hard slog. He completes homework on time, and never tells tales. I’ve never had to admonish them, but if they were to behave as Joe, or Sanjit, or Charlotte sometimes do, I would try to modify their behaviour in the same way. But so far, they haven’t.

“You never tell them off,” says Sophie. I’ve been teaching for a long time and have come up against children’s logic before. In this case, it runs thus: Mrs B tells A off sometimes. She hasn’t told C off at all. So Mrs B likes C more than A. This argument requires the hidden premise that teachers only tell off people they don’t like. But that is false, isn’t it? There’s a confusion between the person, and the acts they commit. I tell Sophie we can use her ideas and feelings in a thinking skills lesson.

Then I’m suddenly reminded of something Martin said to me when he first came into my class last September. “Mr Green didn’t like me. He really told me off for...” (I forget the reason.) I’d dismissed this remark without a second thought. Now I’m giving it a third.

At home I tell my daughter that my class thinks I have favourites. She is considerably older than Sophie, but recalls being nine clearly. “I remember my teacher telling me off horribly about my writing because it didn’t lie all in one direction. She kept saying it spoilt my work - but I thought it was all right. I didn’t like her after that because she kept on pointing it out. I thought at the time she didn’t like me.”

So, tomorrow, I’m going to ask a few other pupils if they think teachers in general have favourites; if they think I have favourites and, if so, what makes them think that. I’m going to find out why you, Sophie, thought Mr Bromley didn’t have favourites. Then on to the big issue with the true premise: “Teachers correct pupils to help them with their learning or their social behaviour.”

Next, we’re going to add another true premise: “Mrs Bews is a teacher.”

Finally, we draw our valid (and true) conclusion: “If Mrs Bews corrects pupils, it is to help them with their learning or with their social behaviour.” But I realise Sophie has raised a whole lot of new questions for me.

Children’s names have been changed.Jean Bews teaches Year 4 at St Leonard’s primary school, Bridgnorth, Shropshire