What did Freud say about the rational and irrational?

Sigmund Freud is credited with the discovery of the
unconscious mind that if allowed, would cause people to participate in activities that
are considered to be against the natural social order, for instance, murder. With this
discovery, Freud dismissed the idea that man has a fully rational
mind. He further suggested that human behavior is a product of the
interaction between the rational and irrational processes conceived by our mind. This
led to his definition of the three aspects of personality; Id, Ego, and the
Superego.

The Id embodies the
irrational part of the mind and forms the driving force behind what we want and the
pleasure that comes with the satisfaction of those particular wants. The
Ego, on the other hand, represents the rational part of the
mind and forms the driving force behind the reality that we can’t always have what we
want. The Superego, which develops last, is the part of the
mind that records and stores values learned from the environment. It functions by
attempting to enforce the rules learned.

Freud asserted
that the Rational (Ego) and Superego function in the conscious while the irrational
(Id), functions in the unconscious.