The Archbishop's Donald Rumsfeld Questions

In this ongoing spirit of avoiding unclarities (note the use of a double negative here) here are some questions regarding the Anglican Communion:

1. What don't Anglicans know that they can disagree about?
2. What don't Anglicans know that they must agree about?
3. What do Anglicans know that they can disagree about?
4. What do Anglicans know that they must agree about?

• The first is an unknown unknown
• The second is an unknown known
• The third is an known unknown
• The fourth is a known known

Answers with explanations in your own heads, or to me via any means, or specifically add a comment regarding any or all questions. Note that the difference is between what Anglicans must agree about and what they can disagree about. You must present what is unknown first in each case of it being unknown and known (although you can do it in whatever order you like in rough). Show your working - but, I hasten to add, not show you're working.

The best one of those giving a decent response beyond their own heads (the work has to be a known known) gets a prize. The prize is that you can select a Rowan Williams speech or lecture and I'll rewrite it according the Sir Winston Method or similar, so long as I am directed to an electronic version of the original.

By the way, I used to be as unclear as the Archbishop, so, although the pot might be calling the kettle black, I did receive quite a bit of scrubbing and cleaning using bleach, biological powder, detergent, other substances and steel wool some years ago, and my Fog Index did turn into mist.