Have you seen inception? That.
Being honest now existence is a really large subject. I mean are you talking the moment of creation, the meaning of existence, how we exist, do we exist, and so on? I noticed a lot of Christian shit. Firstly i'm not ready to bash anyone's beliefs... *puts bashing gloves on*. Ok now I am. Christianity is complete bullshit. I believe Jesus existed, but there are some major errors in Christian thinking. But thats not what this topic is about. PM me and I'll go more into it, I spent the past 3 years studying this stuff, among other things. I spend a lot of time researching random stuff....
Back to the topic
But my beliefs on existence, so far, are more a collections of random thoughts. I believe that ours is probably not the only universe, and that we are no different or more special, or even more random an occurance than any other thing out there. I also don't feel that analyzing existence is really possible as the number of variables is incomprehensible, even creationism, the simplest explanation, does not cover all bases. And the idea of existence vs the idea of non-existence in which we exist in an ethereal spirit form which is dreaming or controlling us like a puppet show is basically the same thing on different levels, so proving one does not disprove the others. Also you have the radical theories, such as where we access a living body in a different universe when we dream, and that our lives are a dream. I don't believe this however, for obvious reasons which you should be able to figure out that I don't feel like writing. Scientific theories, such as string theory, and even theories about creation, such as the big bang theory, deserve recognition in this discussion even though I don't adhere to them (except the big bang theory, but I have other thoughts on that as well that are off topic and this is long enough). Science, I believe, is incapable of grasping any kind of understanding of existence by its very nature. The theories out there are more explanations for atomic/ subatomic action and movement than an explanation of consciousness, which is more pertinent to our understanding of existence of ourselves. A little fun fact is there is a theory that you don't exist unless you think you exist, which is bullshit to say the least, as a rock does not think it exists but can still fall on your head and crush you in fun, exciting ways. By the way, if you read this far, good for you. Basically this whole thing was me saying I have no idea and neither does anyone else, but hats off to those who try.
I definitely have more to say on this subject but I got bored at this point so I'm just going to sign off here.