Quote Originally Posted by nondescript View Post
Si and Ni are actually very similar. The only difference is that Si applies to sensual info(looks, shapes, colours etc) and Ni to "brainy" info(ideas, concepts etc). That's it-long story made very short.
The similarity lies in the fact both deal with internalized perceptions of the world; either the sensorial world, or the abstract world.
However, Si and Ni are still very different in other aspects. Saying Si and Ni are very similar is like saying Fi and Ti are very similar, aka Feeling and Thinking or Sensing and Intuition...
I don't think it is that easy. But for understanding Si and Ni, your simplified comparison may be sort of helpful to some.