Thomas Aquinas questioned Muhammad’s credentials to speak for God. His question remains uncomfortably relevant. Viewed as a philosopher, Thomas Aquinas is a foundational figure of modern thought. Aquinas asked, what evidence entitles a man to claim that God speaks through him? That’s not an unreasonable question. I would argue it’s an indispensable one — especially in 2026.

As Islam seeks to spread its tentacles across Europe and beyond, Westerners are reluctant to critique it. Instead, the modern instinct is to treat every religious tradition as equally mysterious, equally profound, and equally beyond criticism. But Italian philosopher and theologian Thomas Aquinas had no such inhibitions. Writing 600 years after Muhammad claimed to have received God’s final and ultimate revelation for mankind, Thomas Aquinas dared to ask what credentials the Arab had to speak for God.

Conquest Is Not a Credential

Aquinas’s first question concerned divine authentication. Christianity, as Aquinas understood it, was not simply a collection of moral teachings attributed to a charismatic founder. The claims of Jesus were accompanied by miracles and supernatural signs, understood as evidence that His message originated with God.

Aquinas, therefore, asked a rather awkward question: where were the comparable signs establishing Muhammad’s prophetic authority? His answer was devastatingly blunt. Muhammad advanced his cause through force. Aquinas’s observation that military strength is hardly a divine credential is difficult to dismiss. Robbers have weapons. Tyrants have armies. Conquerors have empires.

That hardly makes them messengers of God!

Desire, Discipline, and the Two Faiths

Aquinas was equally pointed about morality. Aquinas argued that Muhammad’s teaching accommodated bodily desire and offered promises of sensual pleasure. Christianity, by contrast, demands the disciplining of appetite and the elevation of the spiritual life above the gratification of the flesh.

Aquinas, therefore, saw a revealing difference in the two systems: Christianity asks man to master his desires; Islam gives those desires considerably more room to manoeuvre — a point well made by French author Michel Houellebecq in his excellent novel Submission. Houellebecq, who had to go into hiding after his book was published, imagined that French men might easily convert to Islam after discovering how generously it catered to their desires.

Truth, Fable, and the Courage to Question

Aquinas third insight concerned truth. He did not claim that Muhammad taught nothing true. His criticism was subtler: he argued that truths were mixed with fables and serious falsehoods in order to create what we now call Islam. That mixture matters because divine revelation ought to possess an authority and coherence that does not depend upon convenient additions from human imagination. Finally, Aquinas questioned the circumstances surrounding Muhammad’s earliest followers and the subsequent expansion of Islam. He contrasted Christianity’s dependence upon preaching, miracles and spiritual conviction with a movement that, as history records, employed military force to secure submission.

In my opinion, Aquinas was very much on point in his critique of Islam. He refused to confuse popularity with truth, conquest with revelation, or desire with virtue. And perhaps that is the lesson we most need to recover in 2026. A society that is frightened to question religious claims is not tolerant; it is intellectually timid.

Respect for individuals does not require surrendering our capacity to examine ideas, doctrines and claims to divine authority. Aquinas understood something that we seem increasingly determined to forget: truth does not become true because millions believe it, because a movement expands, or because criticism makes us uncomfortable.

Religious claims, precisely because they purport to speak with the authority of God, deserve scrutiny rather than exemption from it. We should be capable of critiquing Islam without hatred toward Muslims or contempt for their dignity. But intellectual charity does not mean intellectual surrender. A free society must be able to distinguish between respecting a person and accepting his theology. And Muslims should be able to handle criticism of Islam without resorting to threats or violence.

The veracity — or otherwise — of Islam is not a medieval question. It’s an urgent question for those of us living in 2026. But I fear, a question the West is much too afraid to ask.

Taken from an article by the same name by James McPherson, journalist and a host on Sky News.