Security is Both a Feeling and a Reality
When people think of security, they may think about risks. Risks associated with break-ins, theft, burglary, assault, etc. How vulnerable are you to these things?
Looking at probabilities of risks makes up the reality of security. You want to minimize your vulnerability to bad things happening. Because in reality, these things do happen to people. Security is a calculation of how likely these things can happen. And weighing risks and taking measures to decrease those risks is what security is all about.
Right? Well, partly.
Security is also very much a psychological reaction to risk and to measures taken to minimize that risk. A sense of well-being comes with the thought that everything is in order and that everybody is safe. Safety and security being one of the fundamental needs of humans, such a psychological reaction can not be understated.
As complex human beings, we need to understand how a security system wards off risky situations so that we have that sense of well-being.