I write as an active Christian, and also as a spokesperson for psychological science as found in most North American universities and colleges, in national psychology exams, and in introductory psychology texts, including my own. I’m sometimes asked how I reconcile my simultaneous commitment to both biblical faith and psychological science, to which I give several answers.

First, faith and science happily co-exist. As the origins of modern science make plain, a humble faith, with its awareness of human fallibility, motivates open-minded, rigorous scientific inquiry. If nature is God’s orderly and intelligible creation, then let us, as rational creatures made in God’s image, explore this handiwork and discover the divine laws. We glimpse this idea in both the Psalms (“the sky above proclaims his handiwork” [Psalm 19:1]) and Paul (“[God’s] invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made” [Romans 1:20]).

So let us observe and experiment, believing that whatever God found worth creating, we should find worth studying, mindful that our ultimate allegiance is not to any human authority or human doctrine, but to God alone. In checking our personal opinions and biases against reality we emulate the empiricism of Moses: “When a prophet speaks in the name of the Lord, if the word does not come to pass or come true, that is a word that the Lord has not spoken.” As Paul advised the Thessalonians: “Test everything; hold fast what is good.”

Second, psychological science supports Christian wisdom. Whether viewed through the lens of ancient biblical wisdom or contemporary science, human nature looks much the same. Four examples:

1. 1. The unity of mind and body: In Hebrew-Christian tradition humans are embodied creatures, not Plato’s immortal souls. Even the vision of afterlife is of a resurrected body. In keeping with this tradition (but not with New Age dualism), today’s cognitive neuroscience is ever tightening the links between mind and brain.

1. 1. Pride: In Christian tradition, pride is the fundamental sin. Its counterpart in today’s psychological science is “self-serving bias”—a powerful and often perilous tendency to perceive and present oneself as better than others.

1. 1. Rationality and fallibility: According to biblical teaching, humans are made in the divine image, yet they are finite and error-prone. In recent psychological science, the emerging human image similarly combines remarkable cognitive capacities and illusory thinking.

1. Behaviour and belief: Faith predisposes action, Christian thinkers have often reminded us, yet it also grows through obedient action. Amen, say social psychologists: attitudes influence behaviour, and attitudes follow behaviour (as illustrated by racial attitudes changing after changed interracial behaviour).

Psychological science offers practical wisdom. Psychology’s research-rooted theories offer principles that we can apply in the construction of memorable and persuasive messages, in reconciliation and peacemaking, and in supporting those who are marrying, separating or grieving. As fallible, ever-reforming people, our understandings about hot-button issues, such as sexual orientation, can be informed by psychological science.

Psychological science refutes the new atheist assertion that religion is toxic and dangerous. Massive evidence reveals that religiously engaged people are much likelier than irreligious people to report being “very happy,” to not be divorced, to be nonsmokers, to have never been arrested and to be generous with their time and money.

Others will remind us that psychologists’ worldviews, values and biases subtly penetrate their theorizing and research (a point made not only by Christian critics of psychology, but also by feminists and Marxists). Should we therefore replace a psychology that aims to be value-free with a psychology that expresses our own values and assumptions—with, say, a Christian psychology? The late British neuropsychologist Donald MacKay worried about those who are eager to inject an ideology, even a Christian one, into psychology. He argued that the Christian psychologist’s obligation is to “tell it like it is,” knowing that the author of the world is at our elbow, a silent judge of the accuracy with which we claim to describe the world he has created. In this sense our goal is objective, value-free knowledge. If our limitations, both intellectual and moral, predictably limit our achievement of this ideal, this is something not to be gloried in but to be acknowledged in a spirit of repentance. Any idea that it could justify a dismissal of the ideal of value-free knowledge as a “myth” would be as irrational—and as irreligious—as to dismiss the idea of righteousness as a “myth” on the grounds that we can never perfectly attain that.

For MacKay and others of us, a Christian psychology is one that is faithful to reality. If God has written the book of nature, it becomes our calling to read it as clearly as we can, remembering that we are humble stewards of the creation, answerable to the giver of all data for the accuracy of our observations. Indeed, it is precisely because all our ideas are vulnerable to error and bias—including our biblical and theological interpretations as well as our scientific concepts—that we must be wary of absolutizing any of our theological or scientific ideas.

Sidebar: My Assumptions

As a Christian monotheist and a psychological scientist, I approach life and work with two unoriginal assumptions:

1. There is a God.

2. It’s not me (and it’s also not you).

Together these axioms imply my surest conviction: Some of my beliefs (like yours) contain error. We are finite and fallible. We have dignity but not deity.

This biblical understanding is why I further believe that we should hold our own untested beliefs tentatively, assess others’ ideas with open-minded skepticism, and, when appropriate, use observation and experimentation to winnow error from truth.

This ideal of faith-supported humility and skepticism, arising from a religious tradition that calls itself “Reformed and ever-reforming,” has helped motivate my own research and science writing. Truth cannot be found merely by searching our own small minds; there is not enough there. So we put our ideas to the test. If they survive, so much the better for them. If they crash against a wall of evidence, it is time to rethink. “All truth is God’s truth,” we’re fond of saying. So let the chips fall as they may.

Within psychological science, this ever-reforming process has many times changed my mind, leading me now to believe that newborns are not the blank slates I once presumed, that electroconvulsive therapy often alleviates intractable depression, that America’s economic growth has not improved our morale, that the automatic unconscious mind dwarfs the conscious mind, that personality is unrelated to birth order, [and] that traumatic experiences rarely get repressed . . .

Excerpted from A Friendly Letter to Skeptics and Atheists, by David G. Myers (Jossey-Bass/Wiley, 2008), used with permission.