/mbti/

>What the hell is Si
Introverted sensing, much like Se it perceives the world according to the sensory informations your body gives you, but unlike Se which focuses on the sensory stimuli directly from the outside world, Si focuses on those you have already internalized and are accessible through your memories
In short, it's the function that makes you value remembrance and past experiences
>What's the difference between Ti and Ni?
They're very different, one is a judging function and the other is a perceiving one, for instance
Ti is you analytical function, it makes you use the information you get to come up with your personal system and to compel you to understand the primal reason of why things are the way they are, you'l often hear that Ti makes you ask "why", as opposed to Te which makes you ask "how"
Ni is close to what we refer to as intuition is everyday language, it's about your gut feeling and spontaneous idea of what things are or are going to be, which you may act upon with whatever judging function you have