3. it is always man who speaks with his body There is something that makes the body speak, that makes it produce what we call speech. Miller calls this thing "man" (again, a man in the universal embracing of all people sense of the word).

4. the body is thus the instrument Musical instruments don't play themselves. The human body does not speak by itself. In both cases, instrument and body, someone (man) needs to "play them" to make them make sounds.