heresy

Although many will criticize you for "heresy hunting," you're either going to be orthodox or heretical. As a disciple, you need to know and understand the difference. This multi-page article gives good guidelines: A Biblical Guide To Orthodoxy And Heresy

Carl Trueman, Why and How I Teach Heresy:

And we learn from heresies not simply by refuting them but also by first of all asking the critical question, `Is there a legitimate concern which underlies or drives this particular heresy?’ In almost every case, the answer is yes, and the orthodox can learn from the question as a means of critiquing, refining, and strengthening their own doctrinal understanding and commitment.