THE GOD ARGUMENT: The Case Against Religion and for Humanism. By A.C. Grayling. Bloomsbury. 258 pages. $26.

In “The God Argument,” A.C. Grayling takes on a very old debate, but one that remains as freshly provocative, some would say, explosive, as it was in the days when heretics and martyrs were burned at the stake for their beliefs.

He makes no bones about his own position. Religion should be deprived of its privileged place as a guiding force in society. Humanism, the secular philosophy based on empathy and tolerance, is by far a better alternative.

As for those who may aspire to a more comfortable spot in the middle, the author offers no compromise. One cannot practice both. They are irrevocably at odds.

Grayling, professor of philosophy and master of the New College of the Humanities, London, defines religion as “a set of belief and practices focused on a god or gods.” Religion, he avers, originated in the stories and myths early man developed as a means of explaining what he could not understand, the sun and moon, weather, the growth of vegetation. Later, as it became more formalized, religion was used by temporal leaders, in conjunction with priests, as a means of social control. While Grayling allows that religion has produced much that is good, particularly in the arts, painting, architecture, music, as well as spiritual succor for those in need, it has largely worked in a coercive manner. Its history is rife with war, torture, the degradation and mutilation of women, homosexuals and, indeed, anyone who dared to offer a challenge to its authority.

Humanism, on the other hand, can be traced back to pre-Judeo-Christian and Islamic times, to the Greek idea of the Good and the search for the best way to live, especially in relationship to others. The definition was widened in the 17th and 18th centuries with the growth of scientific inquiry and the concomitant re-interpretation of humanism, according to Grayling, as, “an attitude to ethics that is based on observation and the responsible use of reason.”

Grayling makes the traditional assertion that the existence of “a god or gods” cannot be proven by strictly scientific means. Indeed, that remains as defensible as the idea that to be “good” because one fears the wrath of an unseen deity is less “moral” than doing so minus the prospect of any punishment or reward. However, Grayling’s contention, based on the thinking of fellow author W.K. Clifford, that it is “wrong, always, everywhere and for anyone to believe anything upon insufficient evidence” sounds as offputtingly strident, and simplistic, as any pronouncement from al-Qaida or the Medieval Roman Catholic Church.

It is a question of degree and tone. Grayling spends a great deal of time talking about the horrors of religious extremism, most of which can hardly be exaggerated or more in need of mitigating. He spends no time at all on the gentler, more privately spiritual forms of belief, a premier one being the deliberately vague “higher power” of all 12-step programs.

His insistence, in a tsunami of dense philosophical verbiage, on trying to fit all searches for a supernatural being into a scientific paradigm comes off as someone trying to violently push a square peg into a round hole. Many readers will agree with Grayling’s basic arguments, but they also may be discomfited by phrases like “the dead hand of religion,” and “we are created diseased by a certain doctor ... and only this doctor has the cure.”

The book is much stronger in its presentation of the modern state of the religion/humanist discussion. Grayling maintains that there are three questions in play. The first is, what or what does not exist? The second, what is the place and volume of the religious voice in the public square? The third, does morality come from a “transcendent source such as divine command, or does it arise from our own reflection on human realities and relationships?”

These points, though hardly groundbreaking, provide an opening for more profitably debatable topics such as the teaching of Intelligent Design in schools. Put bluntly, it remains, for instance, very difficult, beyond ultimately inconclusive questions of probability and logic, to prove the non-existence of “a god or god,” but the story of how the earth developed is infinitely amenable to straightforward scientific investigation. Which battle is it more “rational” to fight?

Grayling’s exploration of the history of both religion and humanistic thought is enlightening and challenging. However, in his characterization of religion, he seems to be exhibiting an emotionalism no real scientist would be comfortable with and no open-minded humanist would find acceptable. Sadly, if Grayling truly wants to change hearts and influence opinion, this approach ensures failure. Those on the humanist side will hear nothing new, and religious “apologists” will be inspired to fight another day.

Reviewer Rosemary Michaud is a writer in Charleston.