What are the 'Four Functional Types' within Carl Jung's theory?

intuition, sensation, feeling, and thinking:

is the answer.

The four functions are somewhat like the four points of the compass; they are just as arbitrary and just as indispensable. Nothing prevents our shifting the cardinal points as many degrees as we like in one direction or the other, or giving them different names…but the one thing I must confess: I would not for anything dispense with this compass on my psychological voyages of discovery.

--------------------------------------------------C.G. Jung, Psychological

• Sensing Perception – The process of collecting concrete data through using our five senses
• Intuitive Perception – The process by which we make connections and infer meanings beyond sensory data

Jung also coined two opposite mental functions that we use to evaluate information or make decisions; ways to Judge, or the Judging functions of Thinking and Feeling:

• Thinking Judgment – The process we use for evaluating information by applying objective and logical criteria
• Feeling Judgment – The process we use for evaluating information by considering what is important to me and you