الْجَامِعُ
The connecting relation that groups expressions together.
The common link may be rational, associative in conception, or imaginative through recalled conjunction. A rational link rests on a shared intelligible category; another link rests on notions that the mind sets together by relation or contrast; an imaginative link arises when experiences have repeatedly associated two images.
The purpose of this classification is to prevent the superficial idea that joined clauses must share vocabulary. Coordination is justified by an intelligible relationship among their meanings, not merely by a repeated word.
KindBasis of associationTypical form
RationalShared conceptual categoryGenus or relation
AssociativeMental pairing or oppositionBenefit and harm
ImaginativeHabitual co-occurrence in memoryFrequently paired images