The claim central to the position of advocates of the ET hypothesis is that aliens are(/were) visiting the Earth. To prove this, they must disprove the null hypothesis that aliens are(/were) not visiting the Earth. That is to say, they must produce something that can only be explained in terms of alien visitations, like an alien, or an artifact with extraterrestrial isotope ratios. Positivists say that the invisible and the non-existant look very much alike. Much as aliens and indisputable evidence of aliens. So how useful is non-supernatural intelligent design(alien version) as a probative tool? Can non-supernatural intelligent design theory(alien version) ever be considered an Epistomology so long as indesputable evidence that supports it's claim(s) remains absent?