Quote Originally Posted by machintruc
If you look at the Enneagram types' and the Socionics types' motivations, rather than their behavior, it is clear that some combinations make no sense since they are contradictory.
This is possibly because Socionic types are actually not inborn, but generated by Enneagram types...
I was thinking along the same lines - Socionics Type represents a social role we adopt (within the 'Socion'). Within a culture, certain roles afford certain rewards, therefore different Enneagram Types will be attracted to different roles based on those rewards and hence some role/Type combinations will be less common than others.