Empiricism can be defined as that philosophical movement that restricts reality to what can be proven to be in the world. ('Proof' residing within a narrow set of criteria.) Theory, from this angle, has no take on reality. The religious parallel is those who restrict the 'stuff' of faith to experience, exclusive of theologising. This tendency can be observed among those particularly struck by a spiritual experience, often restricted to an emotional experience or, at least, an emotional response to the experience concerned. I think here of some of the excesses of the charismatic and pentecostal movements. And, surprisingly, it is to be found among the liberal wing of the church whose theology too often appears as a thin veneer easily peeled away from the rock of experience (experience often couched in psychological terms or a broad, inchoate spiritualism). And then there are, of course, those utterly obsessed with a personal relationship with Jesus (again, narrowly defined).
Perhaps this goes back to the split between theology and spirituality that occurred in the West a thousand years ago or more, and is still so evident today in the progressive wing of the church. In earlier times spirituality and theology were not seen as separate but were united in true theologia. Why exclude theology (in the narrow sense) from our total religious experience? Let the barriers between spirituality and theology soften a bit, and let 'doing theology' be the religious experience (understood in a very broad sense) it so obviously is. It would seem to me that those who do theology well are those for whom theology is a religious experience, breaking down the narrow understanding of religious empiricism. If we were to do this, it would then be possible to reclaim our Christian heritage that understood the doctrine of the Trinity to be the ground for Christian mysticism (rather than some kind of general sense of the incomprehensibility of God being the foundation of mysticism). Theology could then take its place as a language of mysticism. (E.g. the doctrine of the Trinity)