LAST Sunday Pope Benedict XVI expressed regret that “a few passages” in his lecture at Regensburg had caused offence to Muslims — that is, his quotations from the medieval emperor Manuel II Paleologus, most notably the emperor’s remark that everything new in the teaching of Muhammad is “only evil and inhuman, such as his command to spread by the sword the faith he preached”. These quotations, the Pope assured us, “do not in any way express my personal thought”.

Let us assume that the Pope was offering a genuine apology, an admission of moral wrongdoing, rather than just expressing distress in the face of calamity, like “I’m ever so sorry to hear you have had a diagnosis of cancer”. Is there anything more that the Pope should apologise to Muslims for?

I believe there is. In fact, I believe that the Pope really ought to have apologised not for the quotations from Manuel II Paleologus but for his own words in the next paragraph, in which he says that “for Muslim teaching”, it is not contrary to God’s nature for us to act against reason.

This is to saddle all Muslims with a highly implausible theological view that is in no way essential to Islam, any more than it is to Christianity.

The view I have in mind is “moral fideism”. A fideist, basically, is a religious believer with too low an opinion of reason and too high an opinion of what s/he takes to be “the faith”. For the moral fideist, the evidence of reason is inadmissible when considering whether or not a particular kind of action is morally acceptable. Take an example — the Pope’s example, whether it is morally right to use violence or other means of coercion to convert unbelievers to your religion. Suppose that the world’s greatest moral philosophers, scrupulously following the highest standards of moral philosophy, unanimously concluded that this is wrong.

The moral fideist would say, “So what? Reason is a wholly unreliable guide in morality — you may as well read tea-leaves. What matters is what (insert name of preferred sacred text here) says.”

To be sure, both Christian and Islamic moral fideists have offered reasons for their view. One of these is the exclusively Christian claim, widespread in hardline Calvinist circles, that the Fall has so corrupted the image of God in human beings that our moral conscience is altogether untrustworthy.

Another is common to both religions: since God is omnipotent, there are no limits to what he can do, and therefore no limits to what he can command.

But, reasons or no reasons, moral fideism is, to say the least, exceedingly unattractive; and it is easy to see how it can lead to and rationalise all manner of religious fanaticism.

However, it is a grievous mistake to regard it as a “sixth pillar” of Islam, as integral to that religion as belief in one God. For centuries there have been two principal schools of kalam (theology) in Islam, the Mu’tazilites and the Ash’aris. The Mu’tazilites, the school of the majority of Muslim scholars, including all Shias, maintain that reason, so long as it remains consistent with the fundamental tenets of Islam, is an indispensable source of moral knowledge, and will lead the honest inquirer to faith in Allah. And although there have been moral fideists among the Ash’aris — such as Ibn Hazn, the figure cited in the Pope’s lecture — they are marginal thinkers even within that school.

Given, to put it mildly, the edginess of Muslim-Christian relations at present, anyone who feels moved to comment on sensitive matters in this area — not least Muslim doctrine on the legitimacy of violence as a way of spreading Islam — has a stringent duty to represent Islam accurately. As the facts I have rehearsed about Islam and moral fideism are readily accessible, especially to a world-renowned theologian with a vast network of other theologians among his advisers, it has to be said that the Pope is morally culpable for neglecting that duty.

If, however, the Pope were to issue an apology for that neglect, and assurances that he would henceforth respect that duty when commenting on Islam, he would have apologised for everything in his Regensburg speech that might give offence to a reasonable Muslim. Despite all the damage that his speech may have caused to inter-faith understanding between Christians and Muslims, such an apology would give all of us cause for great rejoicing. And there would be two further grounds for rejoicing greatly. Only the most ignorant, or the most cynical, could doubt Pope Benedict’s profound respect and esteem for Muslims, and his fervent desire, as he put it last Sunday, for “sincere dialogue, with great mutual respect”, between the two faiths. And that dialogue may proceed on the common recognition that moral fideism is a dreary and perilous delusion.

Timothy Bartel was a lecturer in the philosophy of religion at King’s College London