QUESTION: Why do so many people insist that there must be one truth, or one right way of doing things?
ANSWER: Because the human conscious mind gets confused by too many different points of view, or too many things to do, or too many different ways of doing the same thing. And the more insecure a person feels, the less he or she can tolerate differences.
Normally, most people are most able to deal with two things at the same time, and three or four things in sequence. Four in particular is a comfortable number, which is why so many important things in our lives are divided into four categories. There are four seasons, usually four choices in multiple-choice questions, four major psychological types in a lot of systems, four major world religions in books on religion, and on and on.
Large numbers are frequently handled by dividing them into groups of three or four. The twelve months of the year are often divided into thirds or quarters. The incredibly complex variety of biological life on earth is divided into eight categories: Domain; Kingdom; Phylum; Class; Order; Family; Genus; Species; with the last four more commonly referred to, and the last two most commonly used.
So, even in a universe of infinite possibilities our human nature likes to organize experience for the purpose of efficiency, effectiveness, and primarily comfort. And the more insecure--meaning disconnected--we feel, the more simple we like that organization to be. This is what gives rise to ideas and desires for one truth, one life, one government, one leader, one language, one path, and one right way of doing things.