Can I commit the 'unpardonable sin' and not know I've done it?

Ted asks about the 'unpardonable sin' we read about in Luke 12:10. Rod talks about how little textual clarification we get about that verse, where Scripture talks about apostasy, the importance of the 'means of grace' in regard to 'God's answer to our fretting', and why it is important that it is the Object of our faith that saves, which is Christ, and what assurance and consolation we can get from that.