The confrontation between Sotillo and Hirsch is an exposure of the basest human
motives, greed and fear. Both characters have both qualities: the greed-motivated
Sotillo is also a coward, and the fear-motivated Hirsch is also greedy (as illustrated
by his conversation with Charles Gould in Chapter 2-5 ,
and the recurring ironic references to him as "merchant" in this scene).
The philosophy of Nostromo argues that this confrontation represents the
essence of the human condition: greed and fear brutally encountering each other
in pursuit of unavailable knowledge and unrealizable dreams.