The ideas in this book are very controversial.

In your thinking, I see only chaos.

A: Are all these ideas your own?
B: More or less.

He treated my idea as one—i.e., an idea—that creates a problem.
(He treated my idea as though it created a problem.)

When one has no useful thoughts, the ability to close one's mouth is important.

an empty/dumb idea

You shouldn't abandon your original idea.
(Here the meaning is that your very first idea is better than the current one.)

You shouldn't abandon your original idea.
(The meaning here is that you came up with a new and unique idea that you shouldn't abandon.)

You're right. I had a similar idea.

(Great minds think alike.)

He's continuing to hide the idea.
(He's keeping his idea a secret.)

I dispute the idea that the Skypeople are all demons.

Your idea about the Sky People is very interesting to me (because it seems unusual)

deep thoughts