In a recent stream-of-consciousness speech by Donald Trump at a weekend event in Iowa, he affirmed that he was a Presbyterian, and then he added, "Boy, that's down the middle of the road, folks, in all fairness. I mean, Seventh-day Adventist, I don't know about. I just don't know about."

His comment was obviously a verbal dart at presidential candidate Ben Carson, who, according to some polls, has surpassed Trump's standing among likely Republican voters in Iowa. Iowa Republicans, of course, are a heavily evangelical crowd, and some Iowans question whether Seventh-day Adventism, Carson's denomination, is inside or outside traditional Christian orthodoxy.

In the last few days, the media has focused on whether Trump was insulting Carson's faith in order to sink his popularity among evangelicals. Trump claims he was not and that he was merely stating his ignorance of the faith.

Taking Trump at his word, it is decent of him to acknowledge that it would have been uncouth to "insult" Ben Carson in this way. Personal insults are the lowest form of political rhetoric. However, Trump overcompensated when he stated in his clarification that he would "never say bad about any religion."

Here, Trump appears to be confusing two things – the criticism of people and the criticism of ideas. While it is certainly wrongheaded to insult Carson personally, it is entirely justified to interrogate Carson's religious beliefs. As Sam Harris and Maajid Nawaz have put it in their dialogue over Islam and tolerance, "no idea can be above scrutiny, just as no people should be beneath dignity."

The Privacy and Liberty Fallacies

Dr. Carson has already addressed the concern about whether he would allow his religious beliefs to affect his governance. On Meet the Press, he said, "I do not believe that religious beliefs should dictate one's public policy and stances."

With this response, he appeared to be reinforcing that cherished secular value in American politics: the separation of church and state. Yet while seemingly sensible and even principled, this statement is as fallacious as it is impractical.

First, it is fallacious because the separation of church and state says nothing about whether voters or public officials should allow their religious beliefs to inform their thinking. The freedom of conscience protects the entire spectrum of religious and philosophical thought, and there is no way – nor can there or should there be a way – to prevent citizens from injecting their beliefs, whatever they may be, into the political process.

Second, Carson's pledge that his beliefs would not affect his public stances is impractical. His claim about keeping his private and public beliefs separate is contradicted by his previous statement during his 

Meet the Press interview, when he said that "a person's religious beliefs are the things that make them who they are – give them a direction in their life."

Indeed, this impracticality is evident in Dr. Carson's own avowed stances, as his private beliefs have very much influenced his positions on public policy. Does anyone doubt, for instance, that his positions on the morality and legality of abortion and same-sex marriage are grounded in his conservative Christian values?

Again, to be clear, allowing his Seventh-day Adventist beliefs to determine his policy stances is entirely legitimate. Philosopher Austin Dacey coined the term "the Privacy Fallacy" to describe the notion that, in an open society, citizens ought to exclude their beliefs from the public sphere.

However, Dacey adds that there is another faulty assumption that plagues our political discourse. He uses the term "the Liberty Fallacy" to describe the contention that religious beliefs should not be criticized, since they are – given their private nature – "beyond evaluation by reason, truth and objective standards of right and wrong" (to quote a précis from the New York Times). It was precisely this fallacy that Trump committed when he declared, in an unusual display of political correctness, that he would "never say bad about any religion."

In short, while Carson is entitled to let his religious beliefs influence his political positions, the public is entitled to question, scrutinize, and criticize them.

Private Beliefs, Public and Foreign Policy

Voters often say that they will vote for a candidate of any religion so long as his or her faith does not affect the candidate's policymaking, but not only is that expectation unreasonable (as explained above), but it is also ahistorical. There are plenty of examples of elected and unelected officials enacting public and foreign policy on the basis of their religious beliefs.

Consider, for example, the Child Abuse Protection and Treatment Act (CAPTA), passed in 1974. At the behest of President Nixon's top aides, John Ehrlichman and H.R. Haldeman, the law contained an added stipulation requiring states that received federal funding to create a religious exemption. This exemption protected parents who relied on "spiritual means," including prayer, to treat their children – including those suffering from life-threatening ailments.

In this case, the private religious beliefs of Ehrlichman and Haldeman – both Christian Scientists who believed in the healing power of prayer – were instrumental in shaping public policy. Such religious exemptions still exist in many states, and, as scientist and religion critic Jerry Coyne pointed out, they have led to the preventable deaths of over 100 children.

Consider, as well, the case of Ronald Reagan, who subscribed to apocalyptic views not entirely different from those of Seventh-day Adventists. (William Miller, whose preachings spawned various strains of Adventism, predicted the return of Jesus Christ in 1844: today, the Seventh-day Adventist Church believes that "Christ’s coming is near.")

 State Senator James Mills at a banquet that "or the first time ever, everything is in place for the battle of Armageddon and the Second Coming of Christ,"

While Reagan was not elected president until 1980, his fascination with the end times was evident during his tenure as governor of California. In 1971, he toldadding, "Ezekiel says that fire and brimstone will be rained upon the enemies of God’s people. That must mean that they’ll be destroyed by nuclear weapons."

Reagan carried this obsession with the apocalypse and nuclear weapons with him to the White House: he had the discredited prophesizer Hal Lindsey brief the Pentagon on nuclear war with the Soviet Union, and he embarked on his famously expensive and wasteful "Star Wars" missile defense system to prepare for the possibility of a nuclear exchange.

Commenting on the president's justification for the program, then-National Secular Advisor Robert McFarlane said that "Reagan's interest in antimissile defense was the product of his interest in Armageddon. Reagan's director of Arms Control and Disarmament, Eugene Rostow – noticing the uptick in U.S.-Soviet tensions following the American military's readiness drills – remarked that, in part because of the president's policies, the world was living in "pre-war" times.

Finally, consider the bans on government funding for research on embryonic stem cells, from state and congressional laws all the way up to the decision-making of President George W. Bush – acts that collectively have impeded perhaps the most promising path toward discovering a plethora of medical treatments. The rationale for these bans, of course, has consistently been a senseless religious-based objection to the destruction of pre-conscious human life.

These examples reveal the price that the country pays by not subjecting religious beliefs to the same scrutiny that other kinds of beliefs – such as those concerning history and economics – are normally and regularly subjected to.

The Necessity of Scrutinizing Religious Beliefs

It is for these reasons that it is entirely justified to question Ben Carson on his religious beliefs and how they influence his positions on matters like abortion, same-sex marriage, and even the proximity of the end times.

Moreover, it is not enough for Carson or his supporters to convince the public that his faith is simply part of mainstream Christianity, as Mitt Romney attempted to do regarding Mormonism: there is much to criticize in the historical foundations and ethical implications of Christian theology (to be fair, all candidates, Christian and otherwise, should expect questions about their deepest beliefs and values).

In addition to learning more about Carson's stances on these issues, such scrutiny will also reveal the nature of his critical thinking – that is, how he collects and evaluates evidence. Carson holds some, at the very least, dubious beliefs about cosmology, evolution, and even basic science (thoughtfully dissected by physicist Lawrence Krauss).

Whatever compartmental expertise Carson has in medicine, it in no way validates his beliefs on these particular topics. Scrutinizing Carson's faith and beliefs is not only justified, it may even be necessary.

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