I believe that somewhere in the universe there is another type of lifeform out there. The universe is too vast for there not to be. We don’t know much about the universe outside of the Milky Way. So there is no proof that there are other life forms but there is no evidence saying there aren’t. We are the main creature in our galaxy and there is little proof of anything else in our galaxy. But outside of our galaxy, there is definitely something out there. We could even assume those lifeforms may be similar to us because who's to say otherwise?

I don't think aliens exist, not how we think they do. If there is life out there, it probably isn't intelligent or not in the way we imagine they are. I think there are too many variables that have to line up to create intelligent life like we have on Earth. But if the universe is as expansive as we theorize it is I guess I'll eat my words.

Fermi's paradox... Since there **should** be alien life out there given the numbers and probabilities, it's precisely the fact that we haven't ever seen it that destabilises the original probability. https://en.wikipedia.org/wiki/Fermi_paradox

"There are more things in Heaven and Earth, Horatio..." Truly, there is no amount of theorising that can answer this age old question once and for all. The question that weighs most heavily is summarised in The Fermi Paradox- where are they? For all the vastness and age of the universe, the chances for life- why haven't we seen it?(1) It isn't implicit in this question that life in the universe doesn't exist outside of our planet. There is a strange sense of foreboding in it, though. In the 90s Robin Hanson put forth a theory called "The Great Filter" (2). It relies on at least one step between the formation of the right star system and the ability for space colonisation exploration being incredibly improbable. The threshold for success is high, the civilisations that pass it are low and the odds of them finding us are lower. Although assuming we last infinitely as a species, it'll happen one day. That's quite a big assumption and it's worth pointing out that we've only taken baby steps into space exploration...there is plenty of time for us to realise that improbability. It's much more fun not to, though. 1.https://www.space.com/25325-fermi-paradox.html 2.https://astronomy.com/news/2020/11/the-great-filter-a-possible-solution-to-the-fermi-paradox

It would be monumentally arrogant to suppose life is exclusive to our planet. We can plainly see that we are made up of VERY common ingredients, which are spread all throughout the universe.

Surely even anything living on another planet for example flora would be classified as an "alien" so I believe one is naive to think that they don't exist anywhere in the universe

Anything alive on another planet is an alien. And although the universe is not infinite, we comprehend it as such because its impossible for us to understand a size that big. So if the universe is infinite that means that everything that can happen has happened an infinite amount of times. Obviously the universe is not infinite and we don't know the probability of life developing on a planet so its impossible for us to know without seeing it, but I think there are bacteria in one or two of Saturn or Jupiter's moons.

They exist, whether it is in the past, present or future.