I've never managed to make it work with an actual rubber duck. Talking to an inanimate object doesn't make me think any differently, but there's something in trying to formulate things to get the LLM to "understand" my problem that triggers the same brain mechanisms I get when explaining it to a real person.
That's a key difference between advice and instruction.
The advice giver cannot know the seeker's situation completely, nor can the advice seeker know the giver's.
An AI cannot be trusted to give The Answer. But you can use AI to explore other perspectives and critique your thoughts—not that its critiques will be correct either. Nonetheless it can help get you on different thinking paths that your normal thought patterns wouldn't guide you on.
But AI? I can ask LLMs questions like:
"A couple is buying a house in Germany. What questions do they typically forget to ask, which they regret not asking, and often wish later that someone had told them to ask?"
And it can fill in the gaps better than when I ask a human the same kind of question.
I don't expect it to be perfect, this could well be a half-arsed boilerplate, but the actual humans who I asked this of, mostly responded "Huh? I don't understand?"
https://chat.openai.com/share/f17b013e-6b24-4b49-9986-78a5e4...
(Note this chat had been given custom instructions, that's why it's responding with this unusual pattern).
What it does probably isn't "comprehension", but we also have no idea what comprehension is so it's not a very good target.