The idea of “the magic circle” is a constant in historical magic. It’s used to delineate an operating area, used as a means for containment or protection for the magician, and the vast majority of magical designs feature the circle in some way or other.
I’ve been told the idea behind using a circle is an old superstition that spirits are compelled to follow lines whenever they find them; I’ve not yet corroborated this, however.
In my own work, I talk about the circle as a way to “mark out” the area but never tell the student he/she MUST use a physical circle as a means of protection or whatever.
My reason is simple: YOU. ARE. THE. CIRCLE.
Or more correctly put, you become the circle through training, discipline, and practice.
If it helps you to have a physical circle beneath your feet, then so be it; you’ll get no argument from me . . . and let’s face it, it looks cool. Yet I’d admonish against letting the circle become a “crutch” when it’s really nothing more than a tool.
Tools are useful, but always remember: part of your quest is to become proficient without the need for tools of any sort (you’ll notice I teach a system using very few tools, and even those are employed sparingly).
If the goal of the magician is to become “more than human,” then this can only be accomplished through training to increase one’s self-reliance, competence, and willpower spiritually as well as physically. Use tools for what they offer but don’t rely on them more than their necessary function (a chalice is necessary to hold wine, for example). The endgame is one of complete independence from anything and anyone who isn’t God Alone.
Remember always that the more dependent you become on a tool, or an entity, or any other thing as absolutely necessary to accomplish your goals, the more that you put in the way of your journey to lasting independence.
On this path, meditation on the Rosary’s Third Joyful, Second Sorrowful, and Second Glorious Mysteries’ spiritual fruits – indifference to our physical circumstances that we may overcome them, control of our physical urges that we may overcome our physical limitations, and a longing for heaven that we may overcome the limitations of the physical plane – can help show you the way.