This is the first of a two-part column. The second part will be published Tuesday.What is meant by “total disability” and “residual disability” under disability insurance policies is often unclear. A recent federal court ruling from Washington state, Simmons v. Paul Revere Life Insurance Co., 2018 WL 558960 (W.D. Wash. Jan. 25, 2018), took a stab at offering to explain the difference. The case involved William Simmons, a 67-year-old dentist who practiced in Seattle and Bellevue, Wash., and who …