Sigmund Freud (1856-1939)
Freud used a psycho-dynamic approach to prove that our upbringing defines the people we become. For instance, children are a product of their parents' treatment of them, not any divine causes.
The conscience as described by Kant, is in fact a product of the unconscious mind, instead of being from God.
Freud coined the term 'ego' to describe the conscious self, which is the personality of a person which everyone can see.
Freud described the concept of the 'super-ego' as a subconscious set of moral controls given to us by outside influences. We learn societal and moral rules through being praised and punished.
These two aspects of psychological activity represent the moral decision making mechanisms.
Moral values are not objective, as Kant claimed, but instead come from our super-ego.
Although we have the freedom to choose how we behave, the super-ego acts as an inner parent, or moral policeman, which rewards good behaviour and punishes the bad. Acting in accordance with the super-ego makes us feel virtuous, and disobeying it makes us feel guilty.
The conscience is the result of the super-ego.
Freud sees the super-ego as existing independently of our basic wants or desires, and sometimes at odds with rational thought.
Freud explained what influenced the super-ego, but not where it comes from.