Hello!
Dialogue is the term when two characters converse.
Hope it helps!
Answer:
It's to support subject/verb inversion (as in "neither do I" or "so do we"). So 'does' is standing in for the main verb, 'discover' because modern English avoids inverting except with auxiliary verbs such as do, can, will. Without 'does', you'd have to say 'Only by ... views of others DISCOVERS ONE ...' which isn't done in modern English.
The weather makes the ship too unruly