Taking Tazz' point further...
1. There is only a material universe, in which matter and energy are interchangeable.
2. Humans are only sentient species within quite a number of light years from this planet, and aliens (if they exist) are beyond feasible and rational distance to travel here (let alone then crash and be captured).
3. Any evidence to the contrary of the above 1 & 2 can be easily explained through the practices of science.
4. Believers in either psychic phenomenon or aliens wilfully ignore ample evidence to keep some invalid theory alive, and do not understand science well enough to apply it in those circumstances.
5. No repeatable, replicated, valid experiments or research has been conducted which has validated any such phenomenon. Any studies that purport otherwise are idiosyncratic.
If anyone has sufficient evidence, feel free to link (anecdotes are not sufficient evidence).
(NB - the views of this post do not necessarily reflect the views of the poster :p Otherwise, why would I even be on this site and practicing RV??? However, I do fully acknowledge that my beliefs and opinions, and the reasons for them, do not conform to the scientific method)