Intention has no 'from' clause. You express the intent as "I want this guy's hours to be 8." It doesn't matter if the UI shows 5, and another mechanism has cha

Intention has no 'from' clause. You express the intent as "I want this guy's hours to be 8." It doesn't matter if the UI shows 5, and another mechanism has changed the value to 9 in the background, your intent to set the value to 8 is unaffected. If, however, you assume the "from" clause and do a +3 instead of =8, you get a new invalid state 12. Encoding intent implies declarative statements as apposed to impaitive statements.