Sister Carrie best embodies Theodore Dreiser's naturalistic belief. How do you understand that?

Sister Carrie best embodies Theodore Dreiser's naturalistic belief. How do you understand that?

Sister Carrie best embodies Dreiser's naturalistic belief that while men are controlled and conditioned by heredity, instinct and chance, a few extraordinary and unsophisticated human beings refuse to accept their fate wordlessly and instead strive, unsuccessfully, to find meaning and purpose for their existence.
Carrie, as one of such, senses that she is merely a cipher in an uncaring world yet seeks to grasp the mysteries of life and thereby satisfies her desires for social status
and material comfort.