In the box was a cat.
Not that you would know it. As far as you can remember, before the box was sealed and the instruments were removed and the sensors and detectors and devices deactivated, a cat was placed into the box.
The theory goes on to state that due to the lack of observers of the box, you can never really tell if the cat is alive or not. Not you at least.
Bear with me.
In the box was a mouse.
And the mouse, of course, was delicious to the cat, and the cat, of course, would eventually go hungry. But as you can see neither, you can never really tell if the cat had eaten the mouse or not. Not you at least.
The only observers of such an event would be the cat and the mouse themselves. But should the cat eat the mouse, there would be no more observer of the cat itself, and so the cat would disappear into a foam of probability, both alive and dead.
On the other hand, so long as the mouse escapes the cat, the system remains entirely physical, entirely observable.
To the mouse, the only world that it can experience is the one where it is chased by the cat. Forever running, forever anxious, forever fearful, forever trapped. Forever chased by a fiend it cannot fathom, a creature it cannot conquer, an enemy it cannot escape. An inescapable probability.
Now imagine, for a moment, if the mouse could find sleep. Forever trapped in a state of anxiety and terror, and yet, its tormentor too, must sleep. And in its sleep it may find rest. And in its rest it may find dreams.
What would it dream about?
Dreams, perhaps, of a peaceful past, a placid perversion without predator present? Dreams of routine, of mundane, of bland, and of dreary? Perhaps a life within a life, a fantasy without a phantasm. An escape without a cage.
Perhaps, in that life, it is the box that is the haze, the cat that is unreal, the chase that is illusion.
As you can see from this thought experiment, Albert, this whole idea is absurd. Either the mouse lives on, forever, in an infinite nightmare, or the mouse and cat system becomes a meaningless cloud of probabilities. Whatever predictions we might make about the system - such as, in the case of a mouse, the recurring presence of nightmares where they are being chased by a creature it cannot escape - are purely theoretical and make no testable predictions about the physical world.