Why is there something as opposed to nothing? Science answers questions concerning the interaction of things. It does not propose a theory for why things exist.
Things come into being for a reason, but it is the reason that is the mystery.
Sometimes I ask myself why existence has had to be THIS way.
I can explain existence. The question is, “is existence understandable and are the explanations of it satisfactory to the particular listener?”
didn’t the guy in your avatar say not to ask meaningless questions? 
Wouldn’t this mean that the reason would need the power to create something out of nothing? And wouldn’t this power in turn need something to create it? This makes as much sense to me as saying something came out of nothing.
Existence precedes essence!
Then you may want to think what do we think as existence (or something).
I think we are generally too sure of too many things, including existence and “something”, whatever it is.
What the hell is “existence”?
Personally, I don’t know.
For a specific object to exist, it seems we need time-space field (or potential), and maybe we are talking about this time-space thing when we think about existence.
But what the hell is time-space?
Some people think everything is illusion.
But what the hell is “illusion”? And how can it be?
To have illusion (or virtual experience), I guess we need some infrastructure.
We need observer and we need projection mechanism of some sort.
But what the hell is “observer (and observing)” and how this projection mechanism can be in place?
Illusion can simply mean that you can’t extricate yourself from the equation - that there is no objective or unchanging foundation for knowledge.
For instance, “why is there something rather than nothing?” is predicated on your own conception of what “something” and “nothing” mean. I could just as easily ask “why is there nothing rather than something?” You can’t, ultimately, get out of your own way with that approach. The ocean doesn’t fit into a spoon.
Well, I think what we are to ask here is about something that isn’t necessarily permanent.
And why the hell there seems to be the equation? How can it be possible?
Why the hell conception is possible?
To identify and classify information, we need memory.
To have memory, we need some sort of mechanism, and time-space or something that host the mechanism, most probably.
Why the hell these things seems to be there? How can it be possible?
Personally, I don’t know. And I’m not going to pretend to know with whatever the theory that isn’t logically valid.
I think we can get a hint by more or less mystical method, by going back and forth different state of awareness, especially very slightly before it vanishes out into the void, so to say. But it’s not easy because it requires utmost precision and stability in the formation of awareness. Otherwise we would be too quickly pushed away from the zone back into “existence” side or sucked into the void.
Wondering and moving around the zone very often and very slowly seem to be the key.
What gives something existence is its ability to be percieved and verified by other people. This is why hallucinations don’t have existence. Although percieved by someone they can not be verified by other people. So there is no reality independent of a particular group of people that agree on what they call reality.
So, the existence depends of perception, and other people.
Now, hallucination can have existence in your perspective.
One day, I had a dream about my friend watching TV. And I woke up with a phone call - from the friend - and when I told him I was seeing him watching certain TV program, and he told me he was actually watching the program. I perceived something and it was verified by others (my friend and his girl friend). And it brings this dream (hallucination) into existence, according to your definition.
Also, how do you verify the perception of others.
I mean, you might be hallucinating others verifying and agreeing with you. 
And what is the minimum number of person to be considered as a group? 2? 3? 5? 7? 9? 13? 42?
Does it mean you don’t have existence if you were left alone on a remote island?
As you can see, it’s NOT that easy to settle this kind of thing.
Your dream only exists in a very superficial sense. Many of the details of what your friend was watching was probably left out of your dream. Such as what was happening on the particular TV show at a particular time.
You can’t verify the perception of others. You can’t know what is going on in the mind of others. You couldn’t be hallucinating if others were to agree with your perception.
A group has two or more of something.
You still have existence on a remote island because existence is the ability to be percieved and verified by others. Someone could take a boat to the island.
We are to ask these type of questions here…rather then someplace else.
Now there shouldn’t be a reason to ask. For we are here, and no other place.
I too had found myself, also asking, yet what good does it do to ask? There’s something and something else…not to acknowledge both is simply someone being unaware.
It’s no wonder how that happen (something) it’s no wonder how that happen (nothing) and it’s not like we’re talking quantum physics here.
It’s quite obvious and simply shown to the eye. To explain it methodically, we must know that things are too, there! There’s no question “why or how did they come into effect?” Always there will be something, and nothing to explain how things come to pass, only thought of…and questions can clarify and analyze. Things came into being existible so they now exist. It’s wild but can be explained easily if perceived well enough.
Scientist had made it clear how the creation of this universe came into existence though. The “big bang” I’ll never get though…
Personally, I don’t think your definition of “existence” is useful/usable.
As it depends on the perception of others which we can’t verify (according to you).
Others can lie, make mistake, hallucinate, as well.
Also, your existence require the existence of others and their ability to perceive and communicate.
So, I think you need to explain about these ( the existence of others and their ability to perceive and communicate), now, in turn, if you still think the definition is usable.
In thinking about it intersubjective confirmation isn’t necessary for existence. Conciousness seems to be the criteria. I know conciousness exists because I am experiencing conciousness and can tell that it is not a lack of conciousness. I must also say that any other conciousness of which I am not conciously aware of must also exist because I have defined my existence based upon my own conciousness. Any other thing could also use conciousness to show existence by noting that they are concious. Since conciousness is all I acknowledge that I know I can not talk of any other existence which I am not aware.
I like this one a little better than the version that requires the agreement of others.
Now, in this version, you need to clear up things like “I”, “knowing”, “consciousness”. “experiencing”, first.
I don’t think it’s going to be easy, though.
Then, you may need to clear up the next part “any other conciousness of which I am not conciously aware of must also exist”, as I don’t think the reasoning you provided is sufficient or clear enough.
And then, you may want to think about the existence of things that do not demonstrate consciousness.
For example, rocks do not seem to demonstrate their consciousness, much, although I do not deny the possibility that they might be showing off their consciousness by their subtle change in size, shape, temperature, etc, through the short or long long very long duration of time.
Rocks react to their environment but a reaction isn’t consciousness. The brain reacts to stimulus as well. Consciousness although associated with areas of blood flow, chemical concentrations and other “physical” aspects of the brain is not conciousness. “Physical” states are observations which is a type of consciousness. Sleeping when not dreaming is the closest I have experienced to a lack of consciousness. Anything but a deep sleep is consciousness(existence). Noticing the distinction in ones mind between consciousness and a lack of consciousness is all that is needed to understand existence. Understanding that there is no physical world is necessary to understand this. The physical world is the collection of what our senses gives us. If there was a physical world it would be lacking in consciousness. Such a world would need consciousness to understand the way in which it exists. A world lacking in consciousness wouldn’t be able to communicate with consciousness. It doesn’t exist in itself. Since lacking consciousness it has no concept of its existence.
I’m not 100% sure of that. I mean, by measuring very subtle pressure/electronic reaction in rocks for long long time, we might find out there are intricate patterns that is similar to “brain wave”.
Probably, it’s not so likely, but I would not shut out this and other possibility that we may find out about the “consciousness” of rocks, one day.
But let’s leave it as I don’t think this is the central point (unless you want to continue).
It’s getting interesting.
Now, how do we know (by ourselves, subjectively) the sleeping state?
I mean, I do have the memory of my consciousness waking up and going into sleep, in different ways.
But I cannot claim that I have the memory of the lack of consciousness.
Do you think we can know (or we can retain the memory of) the lack of consciousness, somehow?
Or are we simply guessing by projecting the tendency observed in our memory of wakung/fading consciousness?
If we cannot recognize the lack of consciousness (because of the very lack of the consciousness) in real-time and if we cannot have the memory of the lack of consciousness, how can we make the distinction of consciousness and the lack of it (again, other than projecting the tendencies we might see in the memory of waking/fading consciousness)?
I think I vaguely understand what you want to say, and probably I won’t agree with it.
And let’s see your take on “the lack of consciousness”, first, since other notions partly depends on that.
In a deep sleep the perceptions that we do have are very faint. Faint perceptions as opposed to lucid ones are closer to nothingness which is the lack of all perceptions. This is an approximation of nothingness. I think we can retain an approximation of nothingness. You can’t remember nothingness as there is nothing to remember. Nothingness has no characteristics and therefore can’t theoretically be experienced.