Some people wear the "5 Sola's" as a badge of honor. Affiliating oneself with the Reformers, after all, is very much like asking to sit at the right and left hand of Jesus. It struck me (on the toilet, actually - how's that for affiliating myself with the Reformation) how absurd it is to pluralize the word "alone". Was there such a thing as math in 16th C. Western Europe? It seems like for the five affirmations to make any sense they would have to be punctuated by the word "or". Is it Scripture alone? Or is it Christ alone? Or is it grace alone? Or is it faith alone? Or is it only to God that the glory belongs?
Now, obviously these "alone's" aren't functioning the same way in each of these mottoes - Scripture alone is the rule of the Church's life while Jesus alone is the source of our salvation and grace alone is the ground of said salvation; faith alone is the only means by which it can be received and the credit for all of this can only be attributed to God. What those clarifications demonstrate, though, is just how insufficient the word "alone"really is to describe something as rich and complex as God's plan of salvation.
Each "sola" is so porous that they could never serve as firm doctrinal boundaries; a fact which is easily seen in the constant haggling in Reformed circles over whether one of the sola's has truly been transgressed or not. What does it even mean for God to receive all the glory? Don't believers share in that glory by virtue of our union with Christ? And what about "faith alone" and "grace alone"? The complex relationship between faith and works is almost universally described as involving some kind of necessary dependence (even if that dependence is the construal of works as the necessary outgrowth of faith) - so Lordship salvation somehow can be held without denying this sola while those who entirely stand on it can be soundly rejected. The role of the Scriptures as an authority has been the center of just as much controversy, since it's not clear exactly HOW Scripture should function as an authority (the regulative principle being one example of this question). Obviously countless examples could be given (does Wayne Grudem deny sola Scriptura in his view of prophecy?) - but I'm left wondering exactly what the practical value of these slogans are.