In Charlotte Mason’s Volume 2, Parents and Children, in Chapter 16, Discipline, she talks about the difference between a system and a method. She is presenting a method of education rather than a system. Here are some thoughts on the difference, from an online discussion of Volume 2.
Think of caring for babies. Some baby care manuals are systems, where you are given very specific instructions for exactly when to feed, diaper, play with, ignore, bathe, etc. the baby. Some baby care manuals are methods, where you are given some general principles but you have to use your own judgment to apply those principles to your specific baby. I’ve noticed that the systems are very popular, and I think in part that’s because they help us feel like we are doing the right thing when we don’t feel confident in our own judgment. What happens, though, if your baby has special needs or doesn’t fit the standard "baby mold" that the system expects? The system stops working. Some parents have the good sense to recognize this and adjust, while others don’t and face serious problems. Even for "normal babies" the system often needs tweaking, and if the tweaking doesn’t happen you can still face problems.
I hope that seems clear without stepping on toes. I am seeing, as I look at Charlotte Mason discussion and commentary on the web (and especially at commercial or almost-commercial sites), a distressing tendency to systematize her method. Instead of principles we’re given specific checklists. Instead of guidelines we’re given schedules. Schedules are good when used as a tool, and looking at others’ schedules can be very helpful, but having a "CM schedule" is not the same thing as applying her principles in the home. In some ways I think that the List of Attainments has become a systemization of CM for some of us as we work to check off the items on the list rather than focusing on applying the broader principles.