Don't just tell me what you'd like to be true.

This is from Greg Egan's 1999 novel Teranesia; since there are no hits for ‘Teranesia’ in the Google custom search, I'm inferring that it hasn't been posted before.

Here's a little background. This is a spoiler for some events early in the novel, but it is early; it's not a spoiler for the really big stuff (not even in this chapter). So Prabir lives alone with his father (‘Baba’) and mother (and baby sister Madhusree who is not in this scene), and their garden has been sown with mines for some very interesting reasons that needn't concern us, and Baba has discovered this by being blown up by one. But he's still alive, so mother and Prabir have laid a ladder atop some boxes across the garden, and she's crawled along the ladder to rescue Baba without setting off more mines. But this is harder than anticipated.

She turned to Prabir. “I'm going to try sitting down, so I can get Baba on to the ladder. But then I might not be able to stand up with him, to carry him. If I leave him on the ladder and walk back to my end, do you think the two of us could carry the ladder to the side of the garden with Baba on it—like a stretcher?”

Prabir replied instantly, “Yes, we can do it.”

His mother looked away, angry for a moment. She said, “I want you to think about it. Don't just tell me what you'd like to be true.”

Chastened, Prabir obeyed her. Half his father's weight. More than twice as much as Madhusree's. He believed he was strong enough. But if he was fooling himself, and dropped the ladder …

He said, “I'm not sure how far I could carry him without resting. But I could slide the crate along the ground with me—kick it along with one foot. Then if I had to stop, I could rest the ladder on it.”

His mother considered this. “All right. That's what we'll do.” She shot him a half-smile, shorthand for all the reassuring words that would have taken too long to speak.

(taken from the American hardback edition, pages 50&51)

[Edit: grammar in the text written by me]