The Fermi Paradox postulates that while mathematically there should be a very high probability of extraterrestrial civilizations, the existence and lack of contact with such civilizations is a contradiction – to which there are a wide multitude of different postulated solutions as to why these civilizations either cannot or choose not to be contacted.
One such solution to this is the 'happiness box' theory:
POSTULATE: A cognizant is a brain and only its brain. When the brain terminates function, the cognizant dies and stops perceiving the universe which likewise ceases to perceive the cognizant. The cognizance's feelings, thoughts and personality disappear and they vanish from the universe forever, recoverable only as a pattern of probability through artificial means.
RESULT: All reality is for a cognizant, the electrical currents feeding it information through the brain
RESULT: For the cognizant, a sufficiently accurate simulated reality is absolutely and precisely impermeable as different or unreal from reality
FACT: A reality thus generated in a cognizant's brain by a computer can be anything a cognizant wants. The cognizant will always be in complete control and so the cognizant can tell the computer to create conditions which satisfy it better than reality is able to, for all of time, forever. In this sense, the reality generated by reality outside of the simulation by the universe itself is NOT in the cognizant's control and can create very uncomfortable or hellish conditions.
FACT: It is hypothetically capable that any cognizance capable of experiencing pleasure and pain would prefer the more rewarding environment. This artificial environment may interact on some limited basis with reality as a sort of interface layer to serve the needs of the cognizant but ultimately, the cognizant's experiences come entirely from the simulation if inside a 'happiness box'.
RESULT: A reality generated by a computer is according to neurological rules of function for a cognizant or all sentient species in the universe is preferable to reality: It would not be strange to enter the computer generated reality and never return.