03/17/2014 03:53 pm ET Updated May 17, 2014

Religions Can Criticize Each Other, so Why Isn't It OK for Atheists to Criticize Religion?

Nonbelief is on the rise in America and around the world, and with that rise we see more questioning of the core tenants of major religious traditions. But critical analysis of religious belief isn't something that people do only when leaving a faith. They also do it when trying to firm up and defend one, and when preparing challenges to competing religions.

Many Jews state their belief that Jesus Christ is not the messiah, just as many Christians dispute the holiness of Mohammed. While this difference of opinion has caused violence and oppression worldwide for as long as these faiths existed, there's a growing prevalence in modern cultures where religious people of one faith accept the fact that people of other faiths don't believe the same things they do. In fact, this disagreement about the validity of theological teachings hasn't stood in the way of increased interfaith cooperation, as witnessed by the recent outreach between the Jewish, Catholic, and Muslim communities.

By contrast, when humanists challenge these very same beliefs they are often viewed by the religious community as disrespectful and even outright hurtful. Why is this?

One explanation is that we're seeing religious people of all stripes on the defensive, circling their wagons around religious belief considering the strides being made by those whose morality doesn't come from faith.

Another explanation is that religious criticism from the inside preserves religion whereas such criticism from the outside diminishes it. While a given religion's criticism of competitors is aimed at supporting the critic's claim of being the one true religion, it isn't aimed at invalidating religion itself and putting the whole enterprise out of business. In this way, humanists might be seen as exploiting religious conflict for their own ends.

So while this practice of expressing disdain for humanism's critique of religion while tolerating similar criticism from religious allies is a double standard, the practice is more defensive than malicious. But it divides groups that might otherwise be powerful allies.

Such a divide is a tactical oversight by religious people, as there are many issues on which the nonreligious and religious communities can work together, such as the struggle against poverty and other social ills. While these communities may never agree about the existence of a deity or the value of the supernatural, they can agree that vulnerable people shouldn't starve or be oppressed and that all human beings have an obligation to help those in need.

Indeed, the discussion of these social and political issues is highly regarded in our society. Challenging ideas in this realm is considered fair game and is a regular feature of television shows like "Meet the Press" and "Hardball." So why shouldn't people be encouraged to discuss religion in the same way?

The humanist way forward is for religious people to recognize that those who challenge their beliefs are mostly curious individuals with legitimate questions, regardless of whether or not they happen to believe in a god or hold other supernatural beliefs. Such tolerance is, in fact, becoming more common. A recent survey by the Pew Research Center's Global Attitudes Project showed that nearly half of all Americans believe that a person doesn't have to believe in a god to have good values and be a moral person. Therefore, when religious leaders perpetuate a double standard that paints humanists as outliers, they do a disservice to all.