Sdwings really answered his own question in his first post by mentioning the arrow shot backwards.
Theoretically, if a normal arrow was fired backwards very accurately it would continue in a straight line. But if there was the tiniest displacement at the tail, the aerodynamic force at the tail feathers (now at the front) would become greater with a greater displacement until the arrow “flipped” over the C of G. From then onwards, the aerodynamic forces would reduce until the arrow flew straight as it was really designed to do.
An aircraft needs to be stable in all axes to some extent but unlike an arrow it needs to fly at various all up masses, in other than a straight line, ie have manoeuvrability. The centre of lift and the C of G are therefore placed relatively close together to find a safe compromise between outright stability and reasonable manoeuvrability. To prevent it “flipping” like the arrow fired backwards (a theoretical extreme only mentioned to illustrate the point) the designer works out the safe C of G envelope, which must be adhered to if the aircraft is to stay in full control.