So much has been written about Jung, so in this section we have tried as far as possible to let the great man speak for himself.
It is not the purpose of a psychological typology to classify human beings into categories - this in itself would be pretty pointless. First and foremost, it is a critical tool for the research worker, who needs definite points of view and guidelines if he is to reduce the chaotic profusion of individual experiences to any kind of order. Secondly, a typology is a great help in understanding the wide variations that occur among individuals. CJ Jung
Cognition is a general term defining the processing of information and applying knowledge and the functions involved in synthesising information for example, perception (seeing, hearing, and so on), attention, memory, and reasoning. Its Latin root is 'cognoscere,' which means 'to know' or 'to recognise.'
Whilst Freud’s focus was on his patients’ orientation to the external world, and Adler’s focus on his patients’ world in determining their behaviours; Jung saw this polarity and created his basic concepts of extraverted and introverted attitudes. Some people orient themselves primarily to the world outside themselves, drawing energy from their external environment of people and situations and are thus extraverted by nature. Other people however orient themselves more readily to the internal world within themselves and are therefore introverted by nature and so draw their energies from within their internal environment and thus energised by more solitary, reflective activities.
Jung also discovered that it wasn't just an orientation to the inner world or outer world that made people different from each other, but just as important were the mental activities they were engaging in whilst in those worlds. He called these mental activities functions, based on the 'function' being performed, and these are now often referred to as mental or cognitive processes. Jung described four cognitive processes and said that every mental act consists of using at least one of these four cognitive processes. Furthermore, these cognitive processes are used in either an extraverted or introverted way. He also noticed that there are two major kinds of mental processes and so he classified the functions into two primary groups: Perception and Judging.