Imagine if you existed only as a non existent dream, cause after all dreams don't exist,
but if you existed only as a non existent dream you could dream up anything you choose. Anything at all! Anything you can think of. You have total control over those dreams. What's the first dream you would create?
Not existing is an eternal state. In other words, you'll spend eternity as this non existent dream. Your dreams are going to consist of opposites of what you already have/are. The opposite of eternal is "having limits". So your dreams are going to consist of worlds or universes with limits like these:
-Some things will be certain sizes and distances: The suns of the universes, in your dreams, can only come so close to certain life forms before it reacts them. 
-Some things will be certain colors: Things that are green will have a limit to how much blue is in them or they will change to a different color.
-Some things will react a certain way towards other things: like chemical reactions, or the sounds two hands make when clapped together.
There all limits
-The life forms you create in your dreams will have limits to how far they can reach and see, how fast they can move, etc.
-The things that make the life forms different from each other  will be limits on colors, sizes, opinions, etc. 

As a non existent dream you cannot feel, touch, taste, etc. You don't exist. To experience those physical impressions you have to dream up physical worlds and universes. 
So you create a world much like earth. This world has people on it much like earth. Each with their limitation. They can only reach so far, they can only hold their breath for so long, they can only live for so long, etc. But since you're the dreamer you can lift tall buildings and solve world hunger with the snap of a finger. Over the next however long you become the leader of the universe. You do everything there is to do in every way possible because you are the dreamer and it's your dream. Just like if you or I was to daydream right now. We'd have endless possibilities!

As a non existent dreamer you have no goal, or ambition. They don't exist in you because you don't exist. But in this "physical world" dream you've created there are only 2 things to do. 
1. Better yourself. Good will always be good in the name of progress. 
2. Make things worse. Bad will always be a destructive force that pulls your dreams toward ending sooner than later. 
Which is not what you want. You have eternity to just be a non existent dreamer. And if the only thing to do is dream, then you're gonna dream. And if you don't want the dreams to end sooner than later you'll choose progression over destruction. It only makes since!

So in this dream called "The Physical World" you're trying something new. Things that you don't really have. Ambitions, objectives, limitations. In one dream everyone can fly, in another only some can fly. In another only you can fly. And so on. You have infinite time to create infinite dreams. But there's one problem. In each dream you know the outcome. You have infinite powers to do anything you can think of and it eventually gets boring. How many times can you save the universe? 

Limitations make you want to push further because, as a dream, your true form is infinite/eternal. The limitations you create in your dreams cause a claustrophobic like feeling which leads to objectives, and purpose. When you start off the dream knowing the end there is no purpose. It's like playing basketball with a bunch of new borns. Yea you still gotta make the shots but it'll get old quickly. 
Knowing that you have the power to do or change anything by just thinking about it literally ruins every dream after you first think to yourself "this is getting old". And there's only one way to fix this problem. Create a dream where you don't know that you're the dreamer. In other words give yourself amnesia. Leave yourself hints, some extremely obvious if need be. This way as the dreamer you won't know the outcome. Everything will be mysteries that you solve. Everything will now have purpose. You'll develop a since of pride in your achievements. Now you really get to feel the feelings that you created for this particular dream. When you knew you had God like powers over your dream curing world hunger made you happy for a few seconds. "Post amnesia" you can save one person's life and the feeling that gives you will last a lifetime. 
Using this "amnesia" you have a new game. A game that you can play repeatedly for all eternity. Not only can you dream a life through every person in your physical world's shoes, but each person has around 60,000 thoughts per day. Each thought each person has spawns a new dream world, full of people, that takes over where that thought leaves off. And each thought those people have does the same in an infinite structure. Literally infinite dreams! Science calls them universes.

*Every religion, etc. all agree that we are all connected. All one. As a dreamer are we not one with every single thing that exist in our dreams?

*Infinite life: There will always be a "non existence". Everything that exist at one point didn't exist and at some point will return to not existing anymore. But the actual "realm of non existence" is definitely eternal. Think about it!

The Dream