Person A: (mumbling) "If I could only remember the quadratic equation."
Person B: "What was that?"
Person A: "Nothing. I was just talking out loud."
I heard a version of this today. I've said it myself. But it's screwy. Of course person A was talking out loud - that's what talking is - it's out loud.
People used to say: "I was just thinking out loud." That made more sense.
Idioms run ahead of words,
Racing past the apparent absurd.