For Calvin philosophy professor James K.A. Smith the key question for Christians to consider comes from the New Testament book of John when Jesus, writes Smith, wheels around on two would-be disciples and asks them: “What do you want?”

It’s a question Christ followers still have to wrestle with two millennia after Jesus asked it, Smith says, and to wrestle with it means grappling with a whole host of other questions. To be human, Smith asserts, is to have a heart, so it’s not a matter of whether or not we will love something as ultimate. Rather the question is what you will love. And you are what you love.

The implications of this are at the heart of Smith’s new book—released in April 2016 and titled You Are What You Love: The Spiritual Power of Habit

Sprinkled throughout are folksy anecdotes about Smith’s own life as a father, husband, teacher, struggling runner, coffee drinker and more. He recounts his own transition from eating a Costco hot dog while reading Wendell Berry’s Bringing It to the Table, a book of essays on farming and food that encourages a different approach to eating. It’s an example, he says, of trying to think his way to a new approach while his behavior remained the same. 

Smith writes: “You can’t just think your way to new hungers.” Instead he had to take those “epiphanies of insight” and translate them into new practices. The same is true, he says, for spiritual hungers. “I can’t ‘know’ my way to new habits.”

Such sentiments may seem surprising, coming from a college professor, one who also is editor-in-chief of Comment, holds the Gary and Henrietta Byker Chair in Applied Reformed Theology and Worldview, and is a senior fellow with the Cardus think tank. 

But he says it is exactly that background that makes him most wary of the tendency, even in North American Christianity, to reduce all that we do to the rational, what he calls Descartes’ definition of humans as thinking things. Descartes said, “I think therefore I am,” and that, Smith says, reduces human beings to “brains on a stick.”

You Are What You Love seeks to expand that definition of humans. Knowledge is not unimportant, Smith is quick to note. But it’s not enough. “You can’t think your way to holiness,” he says.

He adds, too, that philosophy, his vocation for almost three decades, has helped him think about the very notion of “pursuing” God.

The ultimate aim of this pursuit, Smith says, is to know that all the while God was attracting us. The heart, he notes, is both an engine and a compass and, as one hymn poetically puts it, we seek God and afterward we know that it was God all along who moved our souls in such a pursuit.