Also, Mercury opposed Jupiter is a very significant aspect.
Rudhyar wrote about Jupiter being the higher octave of mercury. and that they were a cosmic duo which combine to create 'the intellect.'
"Then tribal religion is superseded by universal religion. Jupiter becomes the truly expansive power which sends men upon the quest for a universal — and at the same time a "personal" because immanent — God; or else upon the quest for gold, wealth, and markets ever expanding. Jupiter, the tribal High Priest, becomes then the conquistador and the imperialist, the colonizer and builder of empire. Mercury follows the lead, for he weaves patterns of relationship as Jupiter bids him do so.
Jupiter is first the power of organization of functions; then the power of expansion and assimilation. Therefore Mercury, being the servant or messenger of Jupiter, is first the power of organic inter-relationship, which means the power to receive impressions or sensations and to transmit them through the entire organism by means of the afferent and efferent nerves. At a later stage of evolution, Mercury becomes the power of thought-association and generalization; the substance of the activity of the mind. Through the agency of the mind, man expands his range of activity..."
So Mercury is seen as the 'servant or messenger' of Jupiter. They are a team.
When you see them in opposition, they can be enhanced or debilitated. Or a bit of both..
I have Mercury exactly opposed my Jupiter in Taurus. The opposition is angular, on the Asc/Desc axis. So I have thought a lot about the meaning of Mercury/Jupiter oppositions.
I think that having this opposition in Gemini/Sag is a positive thing. It creates a nice mutual reception and it places the planetary duo in home field advantage.
When this opposition is working well, and being productive, the native will exhibit sound common sense, the optimum in skills of perception and communication, and exude optimism and faith that can inspire and uplift others.
There may be an amazing ability to take the most lofty of higher educational /spiritual concepts and documents and be able to reduce them to their simplest , most basic precepts and communicate them to friends/neighbors and the community. A great teacher/orator/mentor.
But when this opposition is not working effectively, problems may occur. Mercury can be overwhelmed by facts/data/info that brings confusion, overload.
Mercury is met with the task of organizing, processing, communicating, disseminating the information coming from Jupiter. If it cannot keep up, there can be anxiety, disorganization, shutdown in system.
Sometimes people with Mercury opposed Jupiter take shortcuts, get sloppy, exaggerate, but they do tell a good story...