Catholics — especially those engaged in apologetics, evangelization and catechesis — hear a lot about secularism.

There is the challenge of secularism, the spread of secularism, and the dangers of secularism. But what is secularism? If you had to sum up secularism in a single sentence, how would you define it? What are the essential features of secularism?

That’s asking quite a bit, especially when I won’t be able to fully answer those questions in a single column, let alone a sentence. In offering three brief observations about the nature of secularism, I will draw on the thought of three men: a Catholic philosopher, a Calvinist professor and a Russian Orthodox priest.

Charles Taylor is a Canadian philosopher whose 2007 book “A Secular Age” has been widely praised for its thought-provoking insights into secularism. Taylor is especially keen to challenge the “secularization theory” — the belief that as modernity and science spread, religious belief will decrease, eventually becoming either rare or extinct. This is a presuppositon of most so-called new atheists, who pit science against religion and reason against faith. This leads to secularism being understood as the absence of belief in God. Taylor, however, distinguishes between three sorts of “secular.” The first is the classical understanding, referring to the earthly, temporal order. The second is the widely accepted notion of the absence of religious belief and participation. The third is Taylor’s definition of secularism being “a move from a society where belief in God is unchallenged and indeed, unproblematic, to one in which it is understood to be one option among others, and frequently not the easiest to embrace.” This is unique to the modern era of human history, for people are now able to embrace “a purely self-sufficient humanism” aimed as material flourishing, without consideration of a transcedent order and reality.

James K.A. Smith is a professor of philosphy at Calvin College whose book “How (Not) to Be Secular” (2014) is a sort of CliffsNotes version of Taylor’s book. Smith, like Taylor, points out that “secular fundamentalists” often act as if their confident appeals to science and reason have adequately explained every aspect of reality. This, Smith argues, is only so much “secularist spin” that is, in fact, “the denial of contestability and thus the refusal to recognize secularity.”

Put another way, such secularists have simply created a narrative based on their materialist, scientistic assumptions, but without actually offering either real proof or satisfying explanations for a whole host of things. Among those is the deep sense of unease and malaise people feel or sense because, Smith notes, “our age is haunted,” bringing to mind the stories of Walker Percy and Flannery O’Connor. Percy, an agnostic as a youth, once wrote of his conversion to Catholicism: “This life is much too much trouble, far too strange, to arrive at the end of it and then be asked what you make of it and have to answer, ‘Scientific humanism.’ That won’t do. A poor show. Life is a mystery, love is a delight. Therefore, I take it as axiomatic that one should settle for nothing less than the infinite mystery and infinite delight.” Secular humanism simply does not satisfy hungry souls and searching hearts.

Father Alexander Schmemann was one of the greatest Eastern Orthodox thinkers of the past century. My favorite book of his is “For The Life of the World,” written just over 50 years ago, a profound study of worship and sacramentality. In the final chapter, “Worship In a Secular Age,” He states that he thinks most people have missed the essential core — or grave defect — of secularism. “Secularism, I submit, is above all a negation of worship…. If secularism in theological terms is a heresy, it is primarily a heresy about man. It is the negation of man as a worshiping being.” Father Schmemann points out that secularism is not the same as atheism; in fact, secularism does not try to eliminate God as much as completely change man’s relationship with God. Put very simply, God becomes a commodity for our use. Man was made to adore, but has chosen to be autonomous. And now man is haunted, trapped in his secularist cage.

Carl E. Olson is the editor of Ignatius Insight (www.ignatiusinsight.com) and writes from Oregon.