oh cool that helps me a lot 'cause I noticed the change in
  myself. I'm 43 - be 44 in a couple of weeks. I always tested
  REALLY close to the INFP / INTP line, but I've been finding I
  can more easily be totally INTP at times. I figured it was years
  and years of practicing managing inner turmoil. Not mastered but
  enough but I do better than I once did. === ?Infp and intp
  appear similar after 35-40 because they catch up with their
  inferior functions and the infp begins to display logic and the
  intp shares their Fe. The Scientist and The Philosopher are
  similar as one seeks Universal Laws and the other Universal
  Truths, but since both are closely connected it's the same path
  began in different directions"