Symbolism, Imagery, Allegory
Dillard divides Pilgrim at Tinker Creek into two halves, the via positiva and the via negativa. She symbolizes each section with a different kind of sacrificial offering, though she doesn't come right out and say as much, and she doesn't mention either offering until the last chapter of the book.
Say what? Don't worry, we'll break it down for you—we're Shmoop, and that's what we do.
The offering that symbolizes the via positiva is the wave breast, and the one that symbolizes the via negativa is the heave shoulder. But let's recap, shall we?
There is the wave breast of thanksgiving—a catching God's eye with the easy motions of praise—and a time for it. In ancient Israel's rites for a voluntary offering of thanksgiving, the priest comes before the altar in clean linen, empty-handed. Into his hands is placed the breast of the slain unblemished ram of consecration: and he waves it as a wave offering before the Lord. (14.52)
Nice, normal offering, huh? Thanks for the lamb/cow/ram, God. Now let's take a look at the other kind:
In addition to the wave breast of thanksgiving, there is the heave shoulder. The wave breast is waved before the altar of the Lord; the heave shoulder is heaved […] This heave is a violent, desperate way of catching God's eye. […] God look at what you've done to this creature, look at the sorrow, the cruelty, the long damned waste! (15.13)
If the first offering is a simple display of gratitude, the second form—the heave shoulder—feels more like a calling out of God, an insistence that he witness the perverseness of his own creative habit. The wave breast says thanks, while the heave shoulder laments.
In describing the choice to divide the book the way she did, Dillard says in the afterward, "Philosophers on the via positiva assert that God is omnipotent, omniscient, etc; that God possesses all positive attributes. I found the via negativa more congenial […] anything we may say of God is untrue, as we can know only creaturely attributes, which do not apply to God." The wave breast, then, is an offering to a God whose omnipotence is good and light; the heave shoulder is an offering to one whose omnipotence is baffling and dark.
Importantly, though, both are offerings, and—as we see throughout the book—they represent a duality. Considered together, what becomes clear is that you don't have to unconditionally approve of something in order to respect and revere it.