This is foolish idea, no doubt, so we'll say no more about it.
It is a foolish idea, no doubt, but it passes the time pleasantly.
This is certainly a foolish idea, and we needn't mention it anymore.
I had a foolish idea that I wanted to live forever, not because I was greedy, but because I missed it.
Put away those foolish ideas!
It's time to put away those foolish ideas.
We have to winnow out and punish these foolish ideas.
It's time to put away those foolish ideas and become serious.
Perhaps the most obvious reason why foolish ideas persist is that someone has an interest in defending or promoting them.
