No doubt, the issues students select and the actions students take are (or should be) driven by values, but isn't a central idea a reasoned claim without attached values?
I was wondering the same on PYP Threads. And I quote myself:
This central idea issue troubled me , too.
It seems that all the inquiry that follows is a mere demonstration of what we, as teachers, had already asked the students to prove (regardless of how free they are in their personal inquiries or how well we differentiate instruction, they WILL eventually build up evidence to support OUR statement conveyed in CI).
On the other hand, if the CI would be too loose or "abstract", we wouldn't be able to plan activities or students to engage in an in-depth inquiry. I am still thinking...