posted December 29, 2012 03:02 AM
If we're talking about an intellectual understanding between shared experiences, and ideas between people... I think you want to see how strong Mercury is and where/how many aspects it makes in the synastry you have with another. In particular I would look for connections between Mercury and Venus or Neptune...
If we're looking at the emotional understanding we have with one another, yes... then that would fall under Mercury and the Moon, Venus/Neptune and the Moon connections. (preferably conjunctions, maybe trines so long as the aspects are tight).
For purely psychological, logical understandings not always empathetic but sympathetic in nature...
I suspect there'd be connections/strong aspects with Mercury and Uranus.
I would also imagine people who have connections on the nodal axes, and to the IC/MC as well...
maybe more so important in Composite... I think we'd find that these combinations with strong Libra and Sagittarius placements would be more in tune with what has or is happening to one another... based on these two signs being associated with justice, law, and pursuits of harmony, although in different ways... I think looking for strong Cancer, and possibly Aquarian, Scorpion, and Pisces (water especially) would open each other to deeper understanding overall) And, of course houses, like the 4th house, rulers, and those aspects, 3rd, 9th, and 12th house... rulers, aspects... and in particular with regard to the natural rulers of these... not just where they are personally for each party.
I could be way off... but, this is kinda' my feeling... just my 2bits...