How is Naturalism displayed in Aldous Huxley's Brave New World?

As a belief that the world can be explained in scientific
terms without supernatural or spiritual explanations, Naturalism discounts the existence
of God.  Under the belief of Naturalism, it is man who makes prinicples, not any
deity.

In the New World of Aldous Huxley's Brave
New World, time is measured from the time that Henry Ford created the
assembly line for manufacturing the Model T Ford.  The sign of the T has
replaced the Christian sign of the cross.  Like Ford's assembly line, babies are
manufactured in the Central London Hatchery and Conditioning Centre; there is no need
for procreation sanctioned by any God because genetic engineering has taken its place. 
Hypnopoedia, or sleep conditioning, has replaced religious instruction; the Solidarity
Service serves as a parody of the Christian services as soma is
taken as communion; Obstacle Golf and other consumer activities have replaced any
activities connected to nature.  In short, everyone and everything is manufactured
scientifically.  And, when people die, they are recycled into
gases.

Ten World Controllers run the New World, and
science dictates the lives of the residents of this world.  They control this world with
the feelies, depression is controlled with soma, and the desire for
motherhood by artificial fertility. The advancement of science has affected all
humanity.