The universe is very simple, it runs on potential vs actual.
If something is actual it has a limited lifespan
If something has potential it is immortal
If everything that has potential became actual the universe would cease to exist in a fixed amount of time
That fixed amount of time is set by how much potential the said object had before it became actual
Example: An egg can be anything but once it hatches and becomes a chicken it is set into an actual existence and therefore will expire. Before it was a chicken the egg could have been anything, including everything.
It is important to know this because you are the egg right now
Once you "hatch" you become finite
How you hatch is to lack potential to be something else
When you become fixed you no longer have potential
That includes everything in your life, mostly though for now, your thoughts
When you can not think outside of what you believe you have lost all potential
If you still have potential you understand you know no