they couldn't have their own discernment

a) They/their (plural) contradicts ones (singular) self discernment.

b) Separation (Latin discernere) implies within motion, hence during change...which cannot be owned/possessed/held onto by one being (life) moved (inception towards death).

empty vessel

a) There's no lack (empty) within whole (all perceivable) for each partial (ones perception)...unless one chooses to ignore all (perceivable) for one another (suggested).

b) For a vessel (life) within sea (inception towards death) to be able to float it has to be buoyant... https://webstersdictionary1828.com/Dictionary/Buoyant

c) Ones mind/memory becomes an empty vessel for the suggested information by others IF one ignores perceivable inspiration (sound) moving through by consenting to hold onto suggested information (words).

downloading propaganda

Aka downloading (consent) propaganda (suggested information) into an empty (ignorant) vessel (mind).

use their own minds to see

Seeing implies ones sight within all...focusing on something owned/held onto mentally tempts one to ignore that.