Many anti-evolutionist authors have erroneously concluded that vestigial structures do not exist. They reason that either (1) vestigial organs are actually functional or (2) it is theoretically impossible to demonstrate that a structure has no function (for example, see Ham et al . 1990 ; Batten and Sarfati 2003 ; Bergman and Howe 1990 ; Morris 1986 ). This latter argument is based upon the false premise that negative results are used to demonstrate a lack of function, and that negative evidence is unscientific. These arguments are faulty for three reasons, each discussed below.