It depends how you define it, but “experience” probably needs to play more of a role in theology than it does. How can it not? Taken at its broadest, “experience” simply means everything that happens, all that occurs, as it enters the field of human awareness. Thus, revelation itself is one particular form of experience–the experience of God showing himself; the reading of Scripture is an experience; praying, being baptized, and thinking about the Trinity are all experiences in this sense.
Typically, experience gets slagged, I think, because of two fears. They are two narrowings of the notion of experience. The first is the fear that granting “experience” a role means granting that an individual’s experiences shape their theology. But of course the individual–along with their experiences–shapes their theology: the real question is whether they are going to shape it apart from Scripture (and the Church and its tradition). So bad theology takes the form: “God for me is more like…” Good theology proceeds in the light of revelation, in the form given to it by particular individuals.
The second fear, closely related to the first, is that “experience” will form some kind of second (or third or fourth) source after and potentially against Scripture. It can. But it doesn’t have to. Certain forms of feminism want to leverage women’s experience against parts of Scripture. But if reading Scripture is itself an experience, then their relationship is a bit more complex. Experience is properly the all-encompassing web–from the human side, for experience too is a creature–within which the reading of Scripture is an event, a particular experience. And further, we should not assume we know what we are experiencing. Only after the resurrection, and then sometimes only gradually, did the apostles discover what they had experienced (John 2:22). Note the past tense. Put starkly, the unbeliever thinks they are experiencing life, but the Christian understands it is really death they know (1 Tim 5:6).
All this is to say: spiritual theology is important. And how did we get here? Well, any spiritual writer worth their salt–Augustine, Merton, those collected in the Philokalia–knows that we are often willing to deceive ourselves about what we experience. We only know in part the realities of which the Bible speaks (1 Cor 13:12). As Merton puts it, “Yet we act as if we understood sin and as if we were really aware of the love of God when we have never deeply experienced the meaning of either one” (A Search for Solitude, 23). And sometimes we know them plain wrongly: in 1966, Merton had an affair with a nurse. At the time he talked of the “mysterious, transcendent presence of her essential self,” but later he was able to see it as “incredible stupidity” (The Intimate Merton, 297, 336). The deception is not always so severe, and sometimes, when we are given the grace, we are able to see with gratitude-inducing clarity the traces of God’s work in our lives.
“Experience,” then, is not something that has to be excluded from theology; rather, it has only to be named. And it can be named as limited, healthy, destructive–more theologically, as “sin” or as “grace,” as “death” or as “life.” Indeed, so objective a thinker as Aquinas can say, that “anyone may know,” at least “conjecturally,” that “he has grace, when he is conscious of delighting in God, and of despising worldly things” (ST I-II Q112 A5). A theologian who does not experience the realities of which he speaks, who is not “delighting in God,” will write a theology that at best sounds oddly hollow, and at worst is false and destructive of faith.
But we must trust that Paul’s prayer is for us as well: “I keep asking that the God of our Lord Jesus Christ, the glorious Father, may give you the Spirit of wisdom and revelation, so that you may know him better. I pray that the eyes of your heart may be enlightened in order that you may know the hope to which he has called you, the riches of his glorious inheritance in his people, and his incomparably great power for us who believe” (Eph 1:17-19a).