Ok, I got your point. Given there is no beginning or end of time, single-celled organisms should not have existed in the first place. But since we know this is false, advanced life forms must have always existed.

I know this is a bit hard to wrap around your brain but it is the same as asking "What was God doing before creation?" We mortals will never be able to grasp this with our limited minds and this is where atheism fails.

Sorry, deleted my reply because I was wrong. Checked up an article on Raëlism and saw that they really do believe in an endless chain of advanced aliens.

Thanks, @Michael for your understanding. If you further read the article on Wikipedia, you will realize that in the name of Elohim (who they believe are the aliens), they are trying to hasten the coming of the Anti-Christ (or Dajjal as believed by Muslims).

"Raël stated that humanity has to build an embassy for the Elohim prior to their arrival on Earth and that it must include a landing pad for their spaceship. He stated that it needed to be located on internationally recognized neutral territory so as not to indicate favour towards any one particular nation-state. Initially, Raël sought permission to build it in Israel, explaining this by reference to how the ancient Israelites were once in contact with the Elohim. He also stated that this embassy would constitute the "Third Temple" referred to in Jewish prophecy."

https://en.m.wikipedia.org/wiki/Ra%C3%ABlism

PS: I like how they are so advanced and intelligent that they decided to create mankind and in turn, are visiting us to witness our stupidity."

I wasn't familiar with the set of beliefs until I looked at your link, but I am aware of others who spoke of the Elohim. There is a whole tradition of thinking about aliens who were involved in the creation of the world, ranging from Zechariah Sitchkin and Erich von Daniken.

Personally, I am inclined more towards Jung's perspective of alien encounters. In his book, 'Flying Saucers: A Modern Myth of Things Seen in the Sky', he offers a psychological interpretation. He sees such encounters as visionary experience and as being the equivalent to figures in the secular age, whereas in more religious times, human beings often reported encounters with angels and demons. So, I think that the question which I see is whether aliens, as reported in stories of alien abduction, exist in the external world, or are the manifestations of psychic reality?