The alphabet is not long enough to contain the numbers required.
  Nth degree? Zth degree? Are these temperatures? Dimensions?
  Angles?

  My insight is a metaphor for my visual systems. Where is the
  "in"? What is this "sight without eyes"?

  It's not.

  It's entirely different, only loosely related to my ability to
  perceive the world with my eyes, as an educational tool to help
  comprehend the nature of understanding.   Latin: In - Upon
  Latin: tueri - To Look

  Ah. I see it now. Observables. Yet not "in" but upon.
  Hm.[1]sight-vs-insight

References

  Visible links
  1. http://icopiedyou.com/wp-content/uploads/2015/08/sight-vs-insight.png