Mental Sense-Objects and the Five Sense-Objects Exist Simultaneously

Material sense-objects and mental sense-objects together constitute material form (rūpa); the two are simultaneously produced and manifested by the tathāgatagarbha and are inseparable. If the two were not together, but were separated, then the trichiliocosm would be nothing but a field of color, without shape or substance, without content; then all material forms would be indistinguishable from one another, there would be no trichiliocosm, no existence of material form, and eye-consciousness could not arise either.

If the external world contained only the colors of manifest color, and the mental sense-object were created separately within the supreme faculty based on the material sense-object and the four great elements of the supreme faculty, then the external world would no longer qualify as an external world, and material forms would have no boundaries. Therefore, it is said that the mental sense-object and the material sense-object arise simultaneously and undergo arising, ceasing, and change together; they are created simultaneously by the tathāgatagarbha using the seeds of the four great elements.

By the same reasoning, the mental sense-object and sound, the mental sense-object and scent, the mental sense-object and taste, and the mental sense-object and tangibility are all produced simultaneously and undergo arising, ceasing, and change together; they cannot be separated.