This chart is a model of the relation between Christian theological sources as they function specifically in the Seventh-day Adventist Church. It expresses an ideal, but was conceived while reflecting on how Adventists have actually done theology in the framework of the Wesleyan Quadrilateral. It is not definitive, but rather invitation to discussion.
This Adventist Quadrilateral is intended to be presented in two stages. In stage one, the second tier, the "Spirit of Prophecy," is absent, leaving the original four sources of the Wesleyan Quadrilateral. Stage one is, therefore, a Christian Quadrilateral, since more or less all Christian groups use these sources, though they may differ on how the sources relate to one another.
In this model, Scripture stands alone as the most authoritative theological source, because it is understood to be the product of special Divine revelation expressed by prophets under the inspiration of the Holy Spirit. For the purpose of this model, tradition is understood to be the voice of the church, now and in ages past. Because the Holy Spirit is active in guiding the church into all truth, tradition is also a theological source.
The Holy Spirit is active in shaping the experience and reason of individual Christians, and therefore these must be considered theological sources. But individual reason and experience do not have normative authority because Christians are not to judge one another but submit to one another. It is this mutual submission to the work of the Holy Spirit in each other that allows the corporate Body of Christ to have normative authority.
However, the authority of the church is not absolute, but may be appealed by individuals on the basis of Scripture, which judges tradition. Yet, Scripture, the most authoritative source, must be interpreted on the basis of tradition (i.e. "How do other Christians interpret this?"), reason (i.e. "Does this interpretation make sense?"), and experience ("Does this interpretation make a positive difference?"). Therefore, this model posits a circular process of interpretation and evaluation during which theology is constantly growing.
These four sources work fine on their own, but only if you don't want to have a visible church. The model requires theology to be in a state of flux, and therefore on the basis of the four sources alone it is difficult to get individuals, much less congregations, to come together as a church with common beliefs. The model is essentially a protestant one, and protestants are the most fragmented wing of Christianity.
That's where the fifth source of an Adventist Quadrilateral, the Spirit of Prophecy comes in. The Spirit of Prophecy is the second tier source, between Scripture and the other three. Therefore, it is the Adventist iteration of what I have chosen to call a 'theological mediator,' the category that is the the topic of my next post.