Depending on the point of view, I think that you could also say that Moby Dick was also rooting out an evil, (Captain Ahab and the whalers who were trying to kill him), as well.
jbseth, you are correct. From the whale's point of view, it is the hunters who are evil. Here is a longer extract from "Cosmos and Psyche" by Richard Tarnas:
"One of the most remarkable sequences of synchronicities I have ever observed was a
dramatic convergence of events involving Melville, Moby Dick, and the two planetary cycles we
have been examining in this book. As we have seen, Melville was born in 1819 when Saturn and
Pluto were in conjunction, and also when the Uranus-Pluto square was occurring, which
corresponds to that powerful combination of conflicting complexes and impulses that we observed
in Marx, who was born during the same alignments, and in several especially critical historical
periods such as the mid-1960s and mid-1790s. In Melville and Moby Dick, we can recognize the
potent interaction between these two archetypal complexes: on the one hand, the Uranus-Pluto
themes of the awakening and eruption of nature’s forces in the whale, the unleashing of the
instinctual id in Ahab his act of titanic defiance and the titanic power and creative intensity of the
book Moby Dick itself; and on the other hand, the Saturn-Pluto themes of punitive retribution
against nature and relentless obsession with projected evil, the cauldron of the instincts within Ahab
driving his compulsion for vengeance with inexorable force.
Eleven days after Melville was born, in August 1919, the whaleship Essex departed from
Nantucket for the southern Pacific Ocean, where it was attacked by an eighty-foot whale and sunk.
According to the account later published by the Essex’s first mate, Owen Chase, the whale rammed
the ship deliberately and repeatedly with “fury and vengeance” until it had destroyed and sunk the
ship. The twenty surviving whalers were forced to spend the next ninety-three days unprotected and
starving in rowboats in the open ocean, where most of them eventually died. This fateful voyage,
from its departure through the ramming and sinking of the ship by the whale fifteen months later,
took place during the same Saturn-Pluto conjunction and Uranus-Pluto square of Melville’s birth.
The titanic forces of nature embodied in the whale, a vivid expression of the Plutonic principle of
nature’s elemental power, mass, and instinct, can here be seen as suddenly awakened and erupting
in a most unexpected manner, as is characteristic of the Uranus-Pluto complex.
Yet the whale that
turned upon and destroyed the Essex has also become, like both Moby Dick and Ahab, the
Saturnian agent of judgment, punishment, retribution, and death—precisely reflective of the Saturn-
Pluto complex.Growing up unaware of this dramatic event that occurred so near his birth, Melville in his
early twenties signed on to a three-year whaling voyage, which took him to the same area of the
South Pacific as the scene of the Essex’s sinking. While on that voyage, he happened to meet the
son of Owen Chase, the Essex’s first mate, who loaned him a copy of the father’s original narrative.
Melville was deeply affected by reading “the wondrous story upon the landless sea,” as he later
wrote, “and so close to the very latitude of the shipwreck.”
Exactly one full Saturn-Pluto cycle after Melville’s birth and the sinking of the Essex,
during the very next conjunction of those two planets in 1850–51, Melville wrote and published
Moby Dick. Amazingly, just as Melville was completing his book, in August 1851, with the Saturn-
Pluto conjunction within 4° of exact alignment, the whaleship Ann Alexander was rammed and sunk
by an enraged sperm whale it had been pursuing in the same waters in which the same fate had
befallen the Essex over thirty years earlier—to this day the only two well-documented cases of such
an event. Melville was stunned when he learned of the great coincidence."