الساكت متكلم، والمتكلم ليس بساكت
A silent person is a speaker, and a speaker is not silent.
The first “speaker” may mean someone able to speak, while the second means someone currently speaking. Equating them yields the absurd conclusion that a silent person is not silent.
The remedy is to distinguish the two predicates explicitly: “A silent person may be capable of speech,” and “A person speaking at this moment is not silent at that moment.” Both may be true because they concern different respects.