In the beginning of the story when rainsford tells Whitney to be a realist what does he mean?

Rainsford is imparting his belief that humans are superior to animals..... that animals don't know fear...... that they have no feelings. Whitney, however, believes that anilmals do know fear. Shortly after this conversation, Rainsford will learn that his belief in two distinct classes, the hunter and the hunted, isn't as cut and dry as he believed. Becoming the hunted gives him an entirely different perspective.