The use of the word 'dialectical' in anything to do with evangelical theology is liable to raise some alarm bells for "real" conservative evangelicals. Dialectical theology is something associated with Karl Barth and Emil Brunner, and Karl Barth is often described as 'neo-orthodox' which seems to be a quasi-heterodox rather than truly orthodox position in the eyes of some! (As a matter of fact, reading Barth rather than reading about Barth one cannot help recognising how he strives to be orthodox by constantly grounding his proposals in theologians such as Calvin and Luther). However, at least for the time being, I am goign to stick with 'dialectical' in this particular exploration of the relationship between hermeneutics and evangelical theology.
Nevertheless I recognise the potential for an embedded problem with 'dialectical hermeneutics' namely that if this means 'continuous dialogue' between text, theology and readers of Scripture, does one/the church ever reach a conclusion? After all, not reaching a conclusion, always being on the journey and exalting it as better than the destination is (sometimes) the strategy of liberal theologians and ecclesiastics as they seek to avoid settling on an orthodoxy at odds with this or that particular view they wish the whole church would agree to.
However I do not think a continuous, non-conclusive dialogue is a necessary feature of dialectical hermeneutics. We do not start with a blank sheet of theological paper. Theology is already formed in the church. Orthodoxy is established even if it is also being critiqued and reviewed. Dialectical hermeneutics is (I suggest) about an ongoing dialogue in which the conclusions of orthodox theology are refined and deepened through engagement with Scripture, and our understanding of Scripture is shaped and sharpened through interaction with orthodoxy.