What is a Rebuttable Presumption?
A rebuttable presumption is a detail that the law presumes to be true and fact, unless and until someone proves the presumption wrong. Rebuttable presumptions are most prevalent in case (“common”) law, and are often necessary to protect the rights of certain people while simultaneously allowing claims that might otherwise impede those rights. The most common example of a rebuttable presumption is the concept that suspects charged with a crime in the United States is innocent until proven guilty.
The converse to the rebuttable presumption is irrebuttable presumption.
Presumption of Fitness
The presumption of fitness assumes that every single parent is fit to raise and care for his or her child by default. In order to impede that presumption -- for example, to remove a minor child from an abusive home -- a person or agency must first disprove the presumption. Because the law automatically presumes the parents are fit, the burden of proof is to prove, beyond a reasonable doubt, that the child’s parents are unfit. If a person or agency can successfully do so, they effectively rebut the presumption and can legally interfere with the parents’ rights on a child’s behalf without actually violating the parents’ rights.
Presumption of Capacity
A presumption of capacity is the presumption that every adult is capable of entering into an agreement or giving consent. The presumption assumes that an adult entering into a contract or other arrangement -- including intercourse -- is of sound mind to do so. To disprove capacity, one would have to demonstrate the individual lacked mental capacity due to mental defect, insanity, dementia; being under the influence of alcohol or drugs would also preclude capacity.
Conversely, there is a presumption of incapacity for children. By default, any minor child (under the age of 18) is automatically presumed incapable of giving consent or entering into an agreement. While this presumption is irrebuttable in some instances -- for example, a child can never be found capable of engaging in a sexual relationship with an adult -- there are some circumstances under which the presumption is rebuttable.
Presumption of Innocence
Arguably the most well known rebuttable presumption is the presumption of innocence, which holds that every individual charged with a crime is innocent of that crime unless the state can prove otherwise. The presumption of innocence is perhaps the most difficult presumption to rebut, because the state is charged with the responsibility of proving that a suspect is guilty not only to the judge, but to a jury of 12 peers. The presumption of innocence is so strong that if even one out of 12 jurors doubts a suspect’s innocence, the suspect cannot be declared guilty of the crime with which he was charged.