Sola Scriptura

While browsing a few blogs this morning I was fascinated by this post at Higgaion, Grounds for Dismissal at Wheaton College . Here is what Chris Heard has to say about 'sola scriptura',

I'll say this as plainly and bluntly as I can: the doctrine of relying on "scripture alone" cannot be derived from scripture alone. That is, scripture itself does not promote the sola Scriptura principle

That is, the idea that scripture alone is the source of doctrine, is itself a tradition.