[He sort of understands anyway. He doesn't really have an answer, but he knows the question isn't literal. He's quiet for a moment before he just sighs softly, shrugging slightly helplessly]

It made sense at the time...

[The logic had seemed so clear to him before, now he just felt like a fool.]

I wish I could give you a better answer. Admitting I just made a mistake isn't very... satisfying to hear, I realise.