Good question! It doesn't seem one might make a living talking about God. Most theologians have a day job teaching at universities. Yet their vocation remains to pursue "the science of God." These studies aren't merely academic. Theologians invest in the work of understanding as believers themselves, and for the sake of believers everywhere.
Fourth-century Augustine urged seekers of truth to "believe that you may understand." Later Archbishop Anselm of Canterbury coined a phrase from this idea, "faith seeking understanding," to describe the task of theology. Needless to say, theologians don't make stuff up, spinning theories about divinity from their imaginations or faculties of reason. Scripture and tradition are the central tools of the theologian's trade. Whatever they propose must be grounded in these primary foundations.
In addition, theologians may use methodologies from philosophy, history, and science to stretch toward new horizons of thought, to take in advancements in human learning. Many theologians specialize in certain approaches or subjects. Systematic theology, for example, explores motifs of church dogma: Trinity, Creation, or Incarnation, say. Soteriology is concerned with the workings of grace and the meaning of salvation. Moral theology examines how to discern value choices. Christology meditates on the mystery of Jesus as both human and divine. Ecclesiology studies the church in its mission, governance, and future directions. Pastoral theology considers how preaching, teaching, and liturgy promote the gospel and connect with the lived situations of real people.
I like Jesuit J.J. Mueller's listing of four major influences shaping the path of contemporary theology. The first is the renewed appreciation for Scripture's privileged role in any conversation about God: not the Bible taken literally and fundamentalistically, yet still embraced foundationally. Secondly is historical consciousness: ways of viewing and valuing the past as central or irrelevant, ongoing or finished business. Next is the opening of new avenues of interpretation: feminist, black, LGBTQ+, and liberation readings, among many others. Finally, we have to be mindful of the quickening of global interconnectedness and the responsibility to make theology universally applicable and respectful.
I also love Mueller's acknowledgment that theology isn't the exclusive domain of theologians. We all participate in God Talk with family, friends, coworkers, and in the public sphere of politics and the marketplace. What we say to each other, to children, and to the wider world with our values and decisions is part of the greater work of seeking, understanding, and teaching what we believe.
Scripture: Psalm 119; Wisdom 1:1-7; John 1:1-18; Romans 5:1-11; 1 Corinthians 2:1-16; 2 Timothy 3:10-17; 1 John 1:1-4; 2:7-11
Books: Theological Foundations: Concepts and Methods for Understanding Christian Faith, by J.J. Mueller, SJ. et.al. (St. Mary's Press, 2007)
World Christianity: History, Methodologies, Horizons, by Jehu J. Hanciles (Orbis Books, 2021)