The MBTI code is meant to be a short hand method of indicating a personality type’s top two functions. The best way to understand a personality type is to understand their use of cognitive functions, and in order to see these, one may have to decode them from their MBTI.
We will take INTP as our example for this exercise. The first thing we can see is this type is an introverted type, this means that this types’ dominant function must be an introverted function. The J and P dichotomy refers to whether the judgment and perception located in your top two functions are extroverted or not. Therefore, if you have an extroverted perception function in your top two, then you are a P, and if you have an extroverted judgment function in your top two, you are a J. The INTP is a P, that means that their base form of perception must be extroverted, and from the N and S dichotomy, we can see if the person gathers their information from the Senses or Intuition. Thus, at this point we know that the INTP must using Ne in their top two functions. From the T and F dichotomy we can see if a person’s base form of judgment is thinking or feeling, the INTP is a T, and since the INTP already has an extroverted function in their top two, their Thinking function must be Introverted. Going back to knowing that their introverted function is dominant, we can conclude that there dominant and Auxiliary functions are Ti and Ne, respectively. The tertiary function will always be the suppression function of the Auxiliary, and for Ne, it must be Si. The Inferior function will always be the Suppression function of the Dominant, and for Ti, it must be Fe. Therefore, the INTP’s top four cognitive functions hierarchy is Ti-Ne:Si-Fe.