The characters in the story are unable to understand or explain humans and how they think and speak. Why do you think people fear the unknown?

People fear the unknown because they have a love of and feel a need to be in control. They want to hold something in their grasp, they want to plan their life. For example having a five year plan, this is not a bad thing to have but sometimes people need to learn to let go. The unknown can be scary and good. It comes with blessings but it also comes with risks. You do not know what is coming next and you worry because you don't know what to expect. Though it is like an adventure you can't read ahead in the book because this is life and it is scary. With feelings of needing control people fear the unknown because they have no control over it, they can't understand it until it comes and they can't plan ahead because it is not known what is coming.

Explanation:

You mention a story and I don't know what story you mean but here is why I believe people fear the unknown.

in this text, paine use the word “ye” several times in order to  capture  the  attention of the colonists who   haven't understand the   importance and urgency of his cause. the word "ye" that is the plural of   "thou" is used to call the colonists attention and make the fight for the cause.