originally posted at Homebrewed Christianity
I come from a Methodist tradition that looks to John Wesley as its founder. Wesley utilized a famous quadrilateral to talk about how we do theology.
The four elements were Scripture, Tradition, Reason, and Experience.
I love the quad! I am a proud descendant of Wesley and I still find it quite helpful to utilize the same quad. Here is why I find each element so valuable.
Scripture: No matter how fancy we want to get with our theology (I am looking at you Tillich) or whatever else we want to do (Griffin), it must account for the scriptural witness . I am not saying that we must always begin with scripture (like neo-Orthodox or Open folks) nor am I saying that we must only do scripture – but any 21st century theology must account for it. The Gutenberg and Missionary eras have reinforced a global importance and influence that must be acknowledged for any theology to carry weight. There is just no sense in having a theology that is not thoroughly scriptural if you want it to count widely.
Tradition: I grew up evangelical and developed a disdain for tradition. It was a bad word to me – like religion. It meant thoughtless, empty ritual done on autopilot in rote repetition. I see things a little differently now. Back then, I actually thought that we were free to do whatever we wanted as long as it was meaningful and effective for accomplishing the goal – which was to bring people into a deeper relationship with the living God. Now, I understand that we are all socially conditioned into elaborate human constructions. These constructs (like language or religion) are part and parcel of both the communal/social order and the religious tradition. Tradition and community must be recognized and honored since all theology is contextual theology.
Reason: I loved quoting Colossians 2:8 when I was an evangelist and someone would ask me a better question than I had an answer to
See to it that no one takes you captive through hollow and deceptive philosophy, which depends on human tradition and the elemental spiritual forces[a] of this world rather than on Christ.
It was the deceptive word play that depended on human thinking that was so dangerous to my Josh McDowell faith. I had evidence that demanded a verdict and you had tricky mental gymnastics and endless questions. I had never heard of Neoplatonism and why did I need to? I had Paul and the Epistle to the Hebrews! … Which is to say that I had never encountered the philosophical underpinnings of the New Testament writers nor of my Protestant declarations of faith.
Experience: I know that part of my fascination comes my charistmatic-evangelical roots. I know that part of it is my American protestant upbringing and that it is reinforced by my personality. But I find it on the pages of the New Testament, and I am simply uninterested a religion that is all in the head and not in the heart. I want a full body religious experience. Nice words are fine (and OH how I love nice words) but we have to walk the walk (as they say) and not just talk the talk. Theology must be validated by the community’s experience. 
I always attempt to frame things in the positive. In this case, I will also attempt to reinforce the need for all four by allowing myself to state them in the negative as well.
Scripture: I am not interested in a Christianity that does not engage scripture or does not seek to be faithful to those initial witnesses. We can update, renovate, adapt, evolve and reinterpret … but we must always interact with scripture. It is scripture that we update and reinterpret.
Tradition: Let me say first that I loath tradition for tradition’s sake. It makes be somewhere between vomitous and irate – which is not pretty. But in our global context you can’t just ‘do theology’ as if it were in a vacuum or you were starting from scratch. We are not starting with a blank slate! I did not write the Bible, I am not the first to read the Bible – it was handed to me, was given to me and it is that ‘givenness’ that must be absorbed.
Reason: who wants a faith the un-reasonable? Not me. Plenty of other people do. In fact, this is really in vogue right now. Lots of conservative folks are retreating into their orthodoxy silo and playing their own isolated word games. That is a theological dead-end for the faith. It is a desperate remnant of Christendom monopoly and wholly counter to the very impetuous of the gospel they so proudly claim to defend.
Experience: I am as uninterested in a theology that is not experienced as I am in a faith that is unreasonable.
I have been reading a lot of theology lately in preparation for the 2012 Emergent Theological Conversation. Much of it has been philosophical 20th century theology, some of it has been early century and reformation era. At the end of the day, I keep coming back to the Wesleyan quadrilateral as a framework that works for the inter-active, cross-cultural, multi-voiced engagement of the 21st century.
Bo Sanders: Public Theology 