An objection observes that knowing the meanings of words does not ensure identical speed of comprehension. Repetition, familiarity, strength of memory, and habitual association can make one word easier to retrieve than another.
A speaker might know the dictionary meanings of two synonyms yet recognize the everyday term instantly and pause before retrieving the rarer term. The difference in processing speed is real, and simply stating that both meanings are known does not eliminate it.
The reply distinguishes the logical character of the assigned relation from the psychological ease of recalling that relation. Keeping these levels separate clarifies what conventional and inferential indication each contributes to bayān.