What is a syllabus?

Is it the skeleton of the course, that structure upon which the flesh and musculature of the days and weeks will rest?

Is it a promise?

Is it a contract? a recipe? an agenda, a calendar, a game plan?

Is it a sketch, preliminary to the painting that will emerge? A musical score, which the class and I will perform?

What I'm really asking is, can I just call what I have good enough, and let it go? or do I have to keep working on it?