Too much import is invested in the physical, tangible circle, in the names and sigils and letters drawn around its borders. That is not where the protection comes from. Those things are a lens through which the magician can work, reflections of an understanding and a process of spiritual and magical connectivity that should have already happened. If it hasn't, the best circle in the world won't protect a one and if it has, then the physical accoutrements aren't necessary. Given the way I was taught, I'm very much of the school of "if you can't do it naked at 2am in an empty room you can't do it" mentality. This doesn't mean that i automatically dispensed with tools, rather it means i was forced to examine and study why we used them and what their real purpose was. What is the theory behind each tool? What is the magician trying to accomplish by its use? It's all too easy to get caught up in form and forget function. Nowhere is this more evident, at least in my opinion, than in circles of evocation.
The protective circle of the magician serves several purposes:
1. Protection: this probably sounds like a no-brainer but the circle itself isn't doing the protecting; rather it's a visible representation of an esoteric construct, an understanding, an access to lines of power that the magician should already have created. the real circle isn't contained within any chalk outline or colored cord, rather it's something the magician carries with him or her always. it's the lens through which he sees the world, the cosmology in which she is rooted. It's all the lines of power to which he has access and all the allies the magus has made. It's everything that informs their world and esoteric worldview. Two magicians, no matter how similarly they were trained will never (or should never) have the same protective circle. Their internal construction, their alliances, the way they access power will, at least in small ways, be different. A circle is a very, very personal thing. When I teach magic, I force my students to examine their world-views, their cosmologies, their unique way of looking at the world, and their unique relationships with the Powers. They have to work out for themselves what their best circle might be. I may shield someone within the scope of my circle, but that is a far thing from another magician trying to *work* with my construct. Circles are an expression of personal mastery and part of that is, as the oracle of Delphi cautioned: knowing thyself. Know yourself, your motivations, and what you truly believe about the world inside and out. The corollary to this, by the way, is that the circle will change and evolve as the magician does (or should).
For instance, when I initially trained, I was taught to use a full Solomonic circle yet I reject the Abrahamic worldview and very few of the Beings named in the crafting of the visual representation of the circle meant anything to me. It was very hard to invest with power. Once i thought about it and thought about what my personal cosmology was, and Whom I would call upon if I were ever in danger and threatened and needed to call upon a Power, i dispensed with the Solomonic circle and created my own, rooted in those places from which I draw my power. that is essential: the circle is a magnifier of one's personal power. It is the framework through which the magician can access her lines of power. If the names on the circle don't mean anything to you, it's not going to do that. It's especially not going to do that if the magician doesn't even really believe in the existence of the Powers upon which he 's calling for protection…and many of them don't.
2. Calling Card: The circle provides a snapshot, a slice of who you are, with Whom you're allied, to Whom you're in debt, and Who might owe you…all things by which many spirits define personhood. It's the equivalent of a business card, or the old fashioned name cards that a Regency era lady might leave when making the rounds of her neighbors on morning visits. It gives whatever you are summoning a means of identifying you. You don't just bring yourself into the circle; you bring an interlocking network of alliances that define you in esoteric reality. This is actually massive protection if you think about it: without the magician having done anything other than essentially show up, he or she has announced clearly his or her place in the hierarchy of power within which he or she is working. The magician has announced the Powers that may be called upon in an emergency and that may be vexed should harm come to their ally. The power and number of one's allies is a hint to the power and strength the magus too, something that isn't overlooked by many spirits.
3. Pomp and Circumstance: the care taken with the circle shows respect to the Beings that one is calling. If a magician doesn't know herself to the core, then there is no competent circle. This will become immediately apparent as an evocation progresses. By dotting one's i's and crossing one's t's, the magician is showing respect for the strength and danger of the Powers being called. It's like military pomp and circumstance: could the soldiers do their job without all the fuss? of course, but it is a matter of protocol and morale, acknowledgement of hierarchy, and respect. A properly crafted circle gives you life in the planes of magic. It demarcates each parties responsibilities and expectations. It makes you a player in a very, very ancient game of power. Part of power is knowing when formalities are essential and part of power lies in knowing to the -enth degree the limits of one's power. The arrogance that I see cultivated --undeservedly---by many Western magicians is not an expression of power. It's what they play with instead of power.
In the end, a truly skilled magician doesn't need to draw anything on the floor---no fancy diagrams, no elaborate circles, no embroidered regalia. The circle should be an integral part of him, something that can be called forth at a moments notice to redefine his world.