One likes mental relations and responds to ideas. One's partners will tend to be intellectual, communicative, and youthful. One learns from others especially through conversation and give and take. Mercury in the eighth house focuses the mind in research, investigation, diagnosis, sex, legacies, and death. One likes to perceive and even manipulate motivations.
Relationship often involve mental work, and one can learn from the values of others.
One may be interested in psychic, occult, and mystical things. Mercury in the ninth house is in detriment focusing the mind on higher education, intellectual pursuits, travel, and foreign countries. One may be a teacher or like to learn from teachers. The mind likes to explore philosophy, religion, and diverse cultures. Changes in travel may stimulate learning and growth.