Bursting-bubble theory refers to a legal principle rebutting a presumption. Under this theory, a presumption disappears when the presumed facts have been contradicted by credible evidence. Bursting-bubble theory requires the opponent of the presumption to introduce only that evidence which is sufficient to support a contrary to the presumption. In addition, there must be substantial and believable evidence contrary to the presumed intent. However, the most difficult aspect of the operation of the bursting-bubble theory of presumptions in civil cases is the question of the quantum of evidence necessary to negate the presumption. [Idleman v. Raymer, 183 Ill. App. 3d 938, 942 (Ill. App. Ct. 4th Dist. 1989)].