Polar Opposites in the same way that yellow and purple are. Without the other, each is sociopathic. Faith without Reason is incapable of change, it clings ironcladly to ideas that may or may not be obviously false to everyone else. Lacking Reason, one is utterly insane. Reason without Faith is incapable of action, it clings ironcladly to the pursuit of proof that may or may not be obviously sufficient to everyone else. Lacking Faith, one is utterly insane.