Testing and experimentation would be the high bar of evidence. Then of course there are gradations below that. Observational studies, are just observations aft

Testing and experimentation would be the high bar of evidence. Then of course there are gradations below that. Observational studies, are just observations after all. But because I can say "there is 'no evidence' that there are no aliens" is then the lowest bar, it doesn't mean there 'are' aliens. But the point here is that 'no evidence' is being used as a rhetorical technique to promote actually false findings. Kind of along the lines of simply injecting doubt into a debate in order to detract from real evidence. Like what has been done for cigarettes, sugar, etc...