I need to learn how to speak INTPese.Discussions like this are why naming categories for the different process tandems is useful, as I suggest here: http://www.typologycentral.com/forum...dem-names.html
Aside from the common dominant extraversion, both types are similar from having a "systemic" "arm" judgment. Fe and Ti work together in creating "systems" in different ways. You decide what is important, and then go and build upon it in the outer world. (Fe/Ti are more about harmony, either interpersonal or logical). Since Fi is the preferred end of the "arm", both types are informing and motive focused, which tends to be the most friendly (least directive) on the surface. The common Interaction Style is Get Things Going or Sanguine, so on the surface social skills level, they will appear very similar.
Both types "judge" things the same way, though they "see things differently". Ne/Si is more what I call "circumspective", meaning that their perception tends to "look around"; Ne, at past, present and future possibilities, and Si focusing more on the past. Ni and Se deal more with the present, and "moving forth" into the future, from there. We could call this "aspective", meaning simply "to see". (here and now, or ahead).