D. A. Carson is a great blessing to the Christian church! He recently published another very important book titled The Intolerance of Tolerance.
In this significant work, Carson details the shift in meaning the word tolerance has undergone over the last century. Building from the work of S. D. Gaede, Carson distinguishes between the “Old tolerance” and “New tolerance.” Understanding the New tolerance is simpler if one understands how it departs from the Old tolerance.
The primary distinction between New and Old tolerance is the foundation (or lack thereof) for determining what ought to be tolerated. No one is purely tolerant. Even if there were someone whose laissez-faire approach to life would convince him to tolerate such evils as child abuse, wife-beating, airport bombing, and terrorist beheading—chances are, that same person would almost certainly not tolerate such behavior against himself. It may be okay to tolerate stealing in the culture at large, but it surely is inappropriate to steal from me. What’s the old saying? There’s honor even among thieves.
No one is purely tolerant (thank God!). Yet, tolerance as a theme permeates our culture. Carson shows how damaging the New tolerance definition is. As I said, the main distinction between the New tolerance and the Old tolerance is that the foundation of the Old tolerance appealed to truth obtained through reason and rationality. The New tolerance is based solely on its opposition to intolerance. Listen to Carson,
…The old tolerance draws its limits on the basis of substantive arguments about truth, goodness, doing harm, and protecting society and its victims, while the new tolerance draws its limits on the basis of what it judges to be intolerant, which has become the supreme vice.”
If Carson is right (and I do believe he is), then the new tolerance is nothing short of a thought police force. Those in power have the force to enforce what is tolerable and what is not. Carson goes on to explain how the New tolerance operates as a “defeater belief.” The New tolerance assumes that its definition of tolerance is good and right and, thus, superior to lesser beliefs about tolerance. If the New tolerance judges acceptance of gay marriage as the essence of tolerance, then any belief in opposition of gay marriage is automatically defeated as inferior. There is no appeal to truth and no reasoned argument necessary. The “superior” New tolerance by definition defeats the “inferior” (and thus intolerant) opposition.
The result is obviously a loss of harmony, a loss of community, a loss of dialog, and—ominously—a loss of the freedom to speak and even to think in ways contrary to the New tolerance. As Carson notes, the New tolerance tends to avoid serious engagement over difficult moral issues and simply excludes those moral opinions contrary to its own as non-virtuous and intolerant.
One need not think long about such an approach to see the danger lurking for Christians. The exclusivity of the way of Jesus Christ and the exacting nature of Christ’s commands for sexual purity will undoubtedly be expected to bow before the throne in allegiance to the New tolerance.
 D. A. Carson, The Intolerance of Tolerance (Grand Rapids: Eerdmans, 2012).
 Carson gives credit to Tim Keller for his use of the term defeater belief.