The essence of communication is the reduction of uncertainty. But uncertainty about the world can be reduced in two distinct ways: I can tell you something about the world so you better know what to expect, or I can change the world so that it better conforms to your expectations! The first corresponds to estimation, and is the basis of our usual hands-off information theory. The second corresponds to control, which is fundamentally a more hands-on business.

This talk will give some glimpses into this family of ideas, but you really should go to my student Se Yong's graduation day talk if you want to take the red pill and get a better sense of just how deep the rabbit hole goes....