In researching my earlier post about Machen I ran across a talk given by John Piper in 1993 about Machen’s Response to Modernism. He quotes an address by Benjamin Warfield given in 1909 at the 400th anniversary of Jon Calvin’s birth.
Calvinism is not a specific variety of theistic thought, religious experience, [or] evangelical faith; but just the perfect manifestation of these things. The difference between it and other forms of theism, religion, [and] evangelicalism is difference not of kind but of degree … it does not take its position then by the side of other types of things; it takes its place over all else that claims to be these things, as embodying all that they ought to be.
Piper goes on to summarize:
So he says Lutheranism is “its sister type of Protestantism” and Arminianism is “its own rebellious daughter”. Calvinism’s grasp of the supremacy of God in all of life enabled Machen to see that other forms of evangelicalism were all stages of grasping God which are yet in process of coming ot a full and pure appreciation of his total God-centeredness.
Piper near the end of the Q&A session on the mp3 recording says that those who have errors in their doctrine, who do not hold to the reformed faith, are not heretics but simply ‘defective’, though I would reverse his response and say that it is his baptistic views that are defective. :)