How in the red badge of courage how naturalism is related to the theme?

Naturalism is the belief that nothing happens according to science or anyone's concious decisions but for instincts. It also syas that everything is controlled by nature.

In The red badge of courage, Henry Fleming is an inexperienced soldier who discovers in the events of the war not only his courage but the meaning of life and death.

One example of it is showed when his regiment finds in their path a dead soldier, the majority of the soldiers avoid the corpse, but Henry tries to find in the dead eyes an answer to the question "what happens when you die", and he has conceived that death is simply death, and it is nothing but rest.

This is the way the author leans toward Naturalism, as it is to him, a natural belief that it is not something to flee from or to challenge.