‘It’s called high place phenomenon,’ she continues, clearly unfazed by the fact that I haven’t said anything yet. ‘A scientist called Jennifer Hames interviewed a group of students at Florida State University and found that, for the most part anyway, thinking stuff like that is pretty normal.’

How is that normal?

‘It means that you have a healthy will to live.’

‘How does thinking about jumping off a bridge mean you have a healthy will to live?’ I say at last.

Her eyes brighten at the challenge.

‘Cognitive dissonance.’ I like the way she says it, like she doesn’t assume I don’t know what it means. ‘When you’re standing on a bridge you’re not actually in any danger, are you? Not unless someone comes along and pushes you, which isn’t likely, is it?’

I think of Dan then and quickly conclude that I wouldn’t like to be alone on a bridge with him.

‘It’s all in your head.’ She takes her hand out of her pocket and taps her temple with her finger. ‘When you’re on a bridge, your brain sees the edge and tells you that you’re in danger. So you get scared, but you shouldn’t be scared because you weren’t in any danger, were you?’

I nod, fingers tightening around my phone as the boat jerks suddenly.

‘So later, when you’re trying to rationalise why you were scared, you conclude that it must have been because you wanted to jump, even though you had no desire to.’ She puts her hand back in her pocket and shrugs again. ‘It just means that you’re sensitive to internal cues of danger, which reaffirms your will to live.’

I have no idea what she’s on about, but I like listening to her. She doesn’t talk like anyone I know. She’s not scared if there are a few beats of silence. She just leaves them there.

‘You don’t want to jump. It’s just your brain playing tricks on you. Like now.’ She nods at the sea. ‘Being on this boat is making you think that you’re going to throw up when you don’t actually want to.’

‘I still might.’

She throws her head back and laughs and it’s the most beautiful thing I’ve ever heard. This delicate shiver, like the sound my grandmother’s gold bangles make when she’s clapping roti, that grows and grows until it’s so loud – I can feel it in my bones.

I don’t want her to stop, and try to think of something else to say to make her do it again, but then her chin drops and when she looks at me, smiling at me in that same slow way she did when she asked me if I wanted to jump, it’s as though she’s struck a match and set me alight.