Originally Posted by JayUtah

I would define "definitive" evidence as that which can be answered by one conclusion only and represents the essence of the proposal. "I saw a light in the sky," is an observation that can have many interpretations and causes. Therefore it cannot be considered definitive evidence for any one of them. The scientific method endeavors to construct empirical experiences that reveal definitive evidence -- usually better than evidence in previous studies, which was once defensibly believed to be definitive, but turned out not to be.