As I read Madeleine L'Engle's endearing novel, A Wrinkle in Time, I was captured by the idea of "IT." What exactly is "IT"? Where did "IT" come from? What set Meg apart from everyone else as being able to beat "IT"? Finally, how does this make her heroic?
As I turned these questions over in my mind, I realized that "IT" does not necessarily represent one specific evil. Although it would be easy to say that "IT" is hate (the obvious archenemy of the love that Meg uses to defeat "IT") I do not believe this is the case. "IT," in my opinion, is the culmination of aging, cynicism, and fear.
In the nature in which many grow up, they develop a defeatist attitude, much like that which Charles Wallace seems to possess after being hypnotized by "IT." The idea of the cynicism being a young person's greatest fear would make sense as a metaphor, because once "IT" gets them, they feel helpless, like there is no hope. They are blind to any other schools of thought--just hopelessness.
When Charles Wallace repeats, "You've got nothing IT hasn't got," he is expressing the idea of many adults that over-thinking and rationalizing everything is the superior method. When a person disengages from emotions in this way, they are devoid of the will-power necessary to overcome emotional challenges, and thus they feel that they have no ammunition to defeat their problems.
This way of thinking--over-rationalization--robs a person of their ability to experience and express their feelings, leaving the person robotic and diabolical, compact with bottled up emotions. As Meg defeats "IT" with love, "IT" being cynicism, L'Engle is making a statement about how easy it is to be taken by age and to forget that love and care is the most important thing. "IT" must be broken down with a childlike, boundless regard for truth and genuine will-power--the will-power that can only come from love--as opposed to a cynical person's approach. The cynical will always be forced to cower in fear.