[T]he thing which in eminent instances signalizes so exceptional a nature is this: though the man’s even temper and discreet bearing would seem to intimate a mind peculiarly subject to the law of reason, not the less in his heart he would seem to riot in complete exemption from that law, having apparently little to do with reason further than to employ it as an ambidexter implement for effecting the irrational. That is to say: Toward the accomplishment of an aim which in wantonness of malignity would seem to partake of the insane, he will direct a cool judgement sagacious and sound. These men are true madmen, and of the most dangerous sort, for their lunacy is not continuous but occasional, evoked by some special object; it is probably secretive, which is as much to say it is self-contained, so that when moreover, most active, it is to the average mind not distinguishable from sanity, and for the reason above suggested that whatever its aims may be–and the aim is never declared–the method and the outward proceeding are always perfectly rational.
This is an acute observation by Melville, for the personality type he describes here is indeed ‘the most dangerous sort.’ Its tokens conform outwardly to social and moral expectations at all times even as they reserve their malignancy for occasional and pointed demonstrations, which continue to don the cover of ostensibly reasonable behavior. (Indeed, their general conformance to normative standards earns them the indulgence of others, who are then ready to forgive what may come to seem like only an occasional aberration; the pattern in these aberrations may not be visible unless it is too late. ) These agents know how to commit unpardonable acts under the cover of legality; they are adept at picking and choosing among the offerings of the reasonable and civilized, looking for those rhetorical and argumentative maneuvers that will give their actions the best veneer of respectability. (Perhaps they should remind us–via an inexact analogy–of Nietzsche’s ‘educated philistines;’ outwardly sophisticated but lacking in inner culture.)
Unfortunately for this world, Melville’s ‘most dangerous sort’ is a little too common. Its most devastating and dangerous exemplars are found in the political sphere–like those who commit war crimes while proceeding according to some impeccable logic of statescraft–but the skepticism of their opponents may ensure that their cover is easily blown. Matters are far harder in the domain of personal relationships, especially abusive ones. There, in the private sphere, away from prying eyes, the abuser can concentrate on his ‘special object,’ the abused. Their ‘sanity’ may bring the abused to the edge of insanity; their weapon of choice is very often the questioning of the mental competence of their partner. Their long and intimate relationship with their target has granted them access to weaknesses, secrets, chinks in the armor; these are now mercilessly and ruthlessly exploited by language and action which is artfully cloaked by reason and respectability.
Beware the superficial moral and intellectual education; for its most dangerous effect is to produce precisely the type Melville warns us against.