Imagine you're a boxer and you get into fights all the time, outside as well as inside the ring. You only feel safe with your fists up, but you can't control your arms directly. They only go up when you're facing an opponent. Therefore you need to have an opponent at all times.

This is a metaphor, because real boxers obviously do control their arms.

But substitute certain emotions (e.g. anger, fear) for the arms, emotions with which one is strongly identified, the loss of which causes a greater fear (of disappearing, of death).

When the world around us appears to be that way for good reason (and not because of happenstance), we feel secure and validated.