Rule 660 The presumptions established by this article, and all other rebuttable presumptions established by law that fall within the criteria of Section 605, a…

When a court case involves certain legal presumptions, one side starts with an advantage. The law assumes something is true, and the other side must prove it is not true.

These are called "presumptions affecting the burden of proof." This means if you want to challenge one of these assumptions, the responsibility falls on you to bring enough evidence to overcome it. Simply disagreeing is not enough.