(But what about giving an account of the roles themselves: pain, alertness, distress?)
Why? Consider pain. For a to be in pain is for there to be x, y, z such that: T(x,y,z) and a is in x. But if TR is false then there are no x, y, z such that T(x,y,z), so there are no x, y, z such that T(x,y,z) and a is in x. So a is not in pain.