What is the conflict between Rainsford and Whitney?

The conflict between Rainsford and Whitney rests in how they view the world. In "The Most Dangerous Game," both men disagree about how the act of hunting affects the hunted. Rainsford argues that the world is divided into two groups: the hunters and the hunted. He maintains that animals (the hunted) have little conception of how the hunt invigorates hunters like himself. Rainsford is convinced that animals do not possess emotional intelligence.
For his part, Whitney disagrees. He maintains that animals do fear pain and death; furthermore, they cherish their own survival. 
Rainsford soon discovers that there is truth in Whitney's words when he becomes "the hunted" on Ship-Trap Island. The island belongs to General Zaroff, who hunts men for sport. Like Rainsford, the General believes that "Life is for the strong, to be lived by the strong, and, if needs be, taken by the strong." General Zaroff basically believes that the weak exist for the pleasure of the strong. Rainsford is, of course, thoroughly scandalized by the General's life philosophy, particularly since he puts men in the place of animals.
Eventually, Rainsford expresses his desire to leave the island, but he is constrained by General Zaroff. The latter proclaims that Rainsford must participate in a three-day hunt. This is how Rainsford becomes "the hunted" and experiences the truth of Whitney's words. He learns that "the hunted" (whether man or beast) fears pain and death and desires to survive above all.