And you have yet to give me a good reason why it isn`t possible for a more advanced lifeform to exist. Because sorry to say this, but I've looked literally everywhere for aliens, I really have. I haven't found any evidence to counter my belief is not a correct reason either. That doesn`t proof you are right, it just proof that there is no proof you are wrong.
Yes, it is a perfectly valid justification. If your theory is based on a solid reason, say that we have absolutely no evidence for the existence of aliens, and you literally cannot disprove your theory in any way, then there's a very good chance that it is true.
Whereas if your belief is based on a remote possibility that something exists in a part of the universe that even you admit we literally have no information on, and it is easily disprovable.. Well, The former is obviously a better belief to hold.
We have hypothesized it, thats exactly why we think nobody can ever leave their local group.
Until this hypothesis is tested, which it isn't yet, we'll just have to see. However as of now this isn't an official limit of technology, and it's definitely not a universally held idea.
I`ve already said we don`t know. He just keeps on saying my reasoning is wrong and then continues to reason in the same way. Thats what I`m trying to make him aware of.
I've already acknowledged that we don't know as well, and In fact I've also acknowledged that there is a possibility that you are right. However, your reasoning is less valuable than mine, since it's based on the possibility that something may exist in a part of the universe that we have literally no information about.
To put it more simply, it's not that "we know that aliens exist" or that "we know that aliens don't exist", or even that "we don't know if they exist". The current state of affairs is that "we don't know of any that exist, and there is a possibility that there are some that we don't know about which do exist".
Edited 5/14/2016 16:37:36