When I was growing up, I thought of faith and belief as synonymous. I never had the difference explained to me by a respected authority, and I’m not sure how much a religious education would have helped. When I was younger, I was usually sure of my beliefs, but I’ve had to mature quite a bit to comprehend what faith really means. In the process, I’ve found that the right image can ground me in a deeper understanding of the difference in these two words.

What we translate as “faith” in the New Testament comes from the Greek word pistis, meaning trust. “Belief,” originally referring to trust, had by the sixteenth century come to mean mental acceptance. Belief in something means our mind and imagination can make sense of it, while faith often goes beyond our ability to conceptualize. Faith is an experiential knowing, a sense of connectedness with one’s true nature.

The ineffable quality of faith reminds me of how art functions when it transports viewers beyond what it describes. If both belief and faith can be expressed visually, finding the right images could help us understand the meaning of each more powerfully. We might think of institutional propaganda as the classic example of asserting belief through images. But how exactly can one picture faith?

In John 20, Thomas the Apostle doubts Jesus’ resurrection until he can see and touch him in the flesh. This is the scene of Michelangelo Merisi da Caravaggio’s The Incredulity of Saint Thomas (1601–02), a painting that, unlike others on the same subject, does more than merely illustrate a lesson or support religious doctrine. The artist’s unconventional approach to his subject matter depicts the way faith manifests itself in our own lives. It is a representation of the “unknowing” that is necessary to faith, unlike belief.

This difference lies in the fact that belief is an intellectual assent, where faith is an ongoing act of trust. Faith doesn’t exist outside of life as a framing device. Instead it is a daily commitment, often silent and unnoticed. It’s a fitting description for what we see occurring in the painting. Caravaggio’s version of the Doubting Thomas story is a modest interpretation: the holy nature of the event is not presented in a grandiose manner. Christ’s face is diminished in shadow and the three apostles (Thomas, Peter, and John) appear in a non-idealized way, with signs of age and poverty. Their status is not evident in the way they are dressed, nor do they possess any recognizable attributes. The scene becomes more real with their expressive faces and body language, and the lack of an identifiable setting adds to the feeling that this could be happening anywhere and at any time. As is typical of Caravaggio’s work, the religious figures are humanized, making them more accessible to viewers, and the overall scene is detached from anything that would appear supernatural. Thomas examines a wound rendered with tactile realism like a curious scientist searching for empirical evidence.

If we understand faith not as a proposition to be accepted or rejected but as an invitation, we may begin to participate in a dynamic process of unity. This movement deeper into self and presence becomes a relational experience with God. Caravaggio’s painting reproduces this dynamic in the arrangement of the figures as well as their relationship to us. We are brought into the scene by both our proximity to the figures and their life-size scale. Jesus makes himself vulnerable, answering Thomas’s need (as God answers ours in faith) by guiding the disciple’s hand into his wound as Peter and John are invited to look on. The figures are grouped in an arc and joined as one, their heads united to form a diamond at the top center of the picture plane. The intimacy of faith is heightened by the huddled bodies and attentive faces. The painting is an invitation to the viewer to step into transformation through surrender and love.

Each of us holds a set of beliefs and these color how we see life. Like lenses for different situations, our beliefs help us make sense of things. But faith lights our path with a living quality that guides us to our deepest selves. Once there, we must willingly surrender to what is. Similarly, when we enter the space of the painting, we are invited to participate in a unique moment of transformation. This is partly the result of the artist’s use of co-extensive space, which we stand in as a fourth observer of the wound. Free of distractions, we witness the singularity of the moment. Instead of the clear, even light of belief, Caravaggio employs his famous tenebroso technique to paint the illumination of consciousness as a mysterious light. Jesus and his wounded side seem to be its source, into which the disciples have just stepped. They are poised in mid-movement, emerging from the shadows of ignorance into awareness. When we practice this kind of faith, every moment has the potential for what the Greeks called ecstasis, a stepping out of oneself into the light of our true selves, illuminated by a higher consciousness.

The Incredulity of Saint Thomas presents faith as an intimacy with the body of Christ. As Thomas’s finger enters the wound, the blunt physicality points to the human dimension of resurrection. Witnessing and participating in Thomas’s recognition, we return to our own experience inspired to touch the source of life through our own faith. Belief may sometimes be a necessary starting point. Yet only when we leave behind our limited mental constructs are we free enough to recognize the holy—as Caravaggio did in the messy lives of the people of his day—glowing in beautiful ways.