What Has Existed before the Universe?
The Universe is all of space and time[a] and their contents, including planets, stars, galaxies, and all other forms of matter and energy. While the spatial size of the entire Universe is still unknown, it is possible to measure the observable universe. [From Wikipedia]
to have actual being; be:The world exists, whether you like it or not. [From Dictionary.com]
“The greatest teacher, failure is.”
So, you ask what existed before existence?
Guess what? Before existence, many imply non-existence (We have a 0 in our numbers, which is an empty collection, but this is simply conceptualizing). Though this is impossible, there was no ‘before’. This has nothing to do with the cause – effect state, but simply because we know things (though some have postulated ‘virtual particles’) don’t come INTO existence (again, this shows lack of understanding of logic and reality, as something coming IN would have to come ‘out’ of somewhere else. We know magic doesn’t exist and even if it did, it had to hold to the fabric of spacetime and thus the laws of physics).
To elaborate why there was no ‘before existence’:
Time is the only measurement to use in the ‘before and after’ setting (unless meant spatial, duh). But what is time…how do we actually experience time and how does time relate to anything humans don’t experience? Like the 13.8 billion years you didn’t exist (woah woah, you said nothing comes into existence and now I didn’t exist? Yes, exactly. Though all the material you are existed, you did not. Hold that thought, because it is imperative to understand the state of the universe). Time is the measurement between change.
From the very beginning of the current configuration of the universe (lets say ‘lifespan’), time has moved forward. BUT we know time doesn’t move at the same speed everywhere. We know that time moves faster where ‘gravity’ is higher. But what is gravity? Gravity is the movement (force/energy) of particles/waves that cause fields around it to move in a certain direction. So…the more matter, the more particles/waves that spin, the more inert energy, thus the more gravity. Because time is measured in change/movement (towards entropy), there is a requirement. There is a need for something to change, to have moments between one state to another. if there is no particle then there is no change, then there is little to no time (remember, light is energy/matter too). Imagine there is no matter/energy at all…what is there that would be able to change? To …be time? Nothing. So, they are implicitly connected. Without the universe, there is no time possible.
But…what is the situation with our universe and its ‘beginning’? Well…imagine that we know that change is what is happening from the very start of the universe. In our human words we say it was immeasurably hot. But what does that mean? That means that the frequency of energy was so high, it would burn anything we know to exist as matter. That is why there was no matter yet. But energy can not stay that state for long, so as it moved away from itself (I know, sounds weird), it slowed down and energy turned into matter. Very rudimentary, but as matter and energy meets and matter and matter meets, they form new complexity of elements. Like each element has a different charge/electron amount. Eventually atoms gained cohesion causing molecules of more complexity to exist.
Cool it, you are dead wrong
All the while the universe cooled down and the end state will be where there is no change anymore in the universe. Though I think this moment will only be a fraction of a …well…some length of time very short, causing all condensed cooled down matter to explode into another life…as such…you might consider the only thing that actually can really rebirth, is the universe. In that sense…before the universe (as we know it now) there was the universe.