There are a number of problems with the idea that things move around in the syntax. As mentioned, a lot of people find it completely unbelievable. Matching, rather than movement, seems like a much more natural explanation in many cases. Also, some of the movement explanations are not very strong. Let us look at the following sentence again:
1. Which books do you know where Taro bought?
A lot of people think the sentence is all right. If it IS grammatical, the movement to special landing places (Spec CP) explanation seems a bit weak.
Also, consider the following sentences:
2. He isn’t the boss.
3. Isn’t he the boss?
In 2 and 3, we can just move the negative verb isn’t to make the question.
Now let’s see what happens if the verbal expression is am rather than is.
3. I am the boss.
4. Am I the boss?
We don’t seem to have any trouble moving the verbal expression am in 3 and 4. However, look what happens if the verbal element is a negative.
5. I am not the boss.
6. Am I not the boss?
7. I’m not the boss.
8. Aren’t I the boss?
9. *’m not I the boss?
10. *mn’t I the boss?
In 7, 8, 9, and 10 we can see a clear mismatch depending on the position of the verbal expression.
Anyway, here’s a link to my PowerPoint slides. Have fun!