Truth, in all of its forms, must be the primary goal of a person's life. The pursuit of truth often ends up being the pursuit of God. But when people prefer lying to the truth, things go downhill quickly.
From the book "Strangers in a Strange Land" by Charles J. Chaput:
Over the course of decades, Dr. Peck met patients who didn't fit a standard diagnosis but thad certain recurring traits. These persons showed chronic disregard for the good of others to the point of causing grave psychological harm. They were subtly but pervasively self-centered. Their symptoms were broader than narcissistic personality disorder, but they weren't sociopaths. They knew right from wrong.
But their main shared trait was the habit of lying. They al lied constantly and effortlessly about everything--especially about themselves, to themselves. As such, they were opaque even to highly trained therapists. More important, they were opaque to themselves. For Peck, the "layer upon layer of self-deception" that "people of the lie" build up insulates them so thoroughly from truth that they no longer recognize it. Their own irreproachability is their only truth.
Peck didn't mince words. He calls such persons evil. While he fleshes out his use of that word in his book, he never backs away from it. Peck's "evil" people erect so many defenses against self-examination and repentance that these become almost impossible without a miracle of grace.
"People of the lie" embody Aristotle's teaching on the formation of character. They don't wake up one morning and decide to be cruel. Rather, they accumulate years of decisions to ignore the true good in favor of their own apparent good, until they fully identify their own will with what's genuinely good.
As Peck notes, this reveals itself as a preoccupation with appearances. "While they seem to lack any motivation to be good, they intensely desire to appear good. Their 'goodness' is all on a level of pretense. It is, in effect, a lie". The evasion of truth soon makes their entire lives little more than an intricate ruse.
For these morally crippled creatures, the pretense of goodness salves the scares of conscience that do exist, but have been routinely ignored and abused. "The central defect of the evil [person] is not the sin but the refusal to acknowledge it." We all sin, of course, but the unwillingness to take any responsibility for our sins implies a more deeply damaged spirit. And so the evil person doubles down on his or her lies by cultivating false appearances and scapegoating the innocent.
As Peck puts it, "We become evil by attempting to hide from ourselves. The wickedness of the evil is not committed directly, but indirectly as part of [the] cover-up process. Evil originates not in the absence of guilt but in the effort to escape it."
Strangers in a Strange Land
"Living the Catholic Faith in a Post-Christian World"
by Charles J. Chaput
Published by St. Martin's Griffin
ISBN: 978-1-250-15962-5 (trade paperback)
pg. 113-114