Developments such as these had a tremendous effect on Freud's thoughts, yet the German, Helmholtz, was probably the person who had the greatest influence on Freud's way of thinking by drawing up the law of preservation of energy. This discovery is most likely the reason Freud started looking at people as a closed system of psychic energy that is floating between the conscious and the unconscious part of the human spirit.
Freud explained these concepts by comparing the human spirit to an iceberg. The visible part of the iceberg (spirit) is the conscious part, which consists of everything we know and remember and the thinking processes through which we function.
The unconscious part is made up of everything we have ever learned or experienced, including that which has been "forgotten". A part of these forgotten things are really gone, but the largest part of the unconscious has just been shut out, because it would be annoying to be consciously reminded of it.
The influences of Helmholtz are also visible at other points. According to Freud, the material in the unconscious contains psychic energy. This psychic energy is constantly trying to get into the conscious part, while the conscious part keeps using energy to suppress undesirable discoveries. An expression of unknown powers is, for example, slips of the tongue. These expressions show that our unconscious was not strong enough to keep these powers outside the conscious part.
Id, Ego and Superego
Now we are going back to the theory of the id, the ego and the superego. The spirit of a newborn child just has an id, the instinctive incentives and reflexes that the human beings have developed during the last centuries. The only function of the id is to respond to the incentives. The ego develops itself from the id and from the discovery that the behavior of the id can have tedious results. The superego, a result of a person's socialization, is basically just the conscience, which mediates between needs of the id and the ego. When you are getting older, you start to develop more and more values.