Magic 201: Belief
Reminder: not only do you need a teacher, you need a LOT of structured personal work in order to have the will necessary for belief to matter in the astral or spiritual planes. You cannot get to this stage without a teacher.
I’ve said that the magician contributes to what they see in the astral or spiritual planes, and they do—we can see what we can see—but whether or not a situation is dangerous to the magician does not depend on the magician’s perception. This distinction is important: a tiger trap is still dangerous, even if the person walking on the trail does not notice it. In fact, the trap is more dangerous for not being noticed.
A magician also contributes to any harm they take as a result of interacting with something in the astral or spiritual planes. I mean this several ways: I mean that discourtesy, ignorance, foolishness, or defects of character, wisdom, etc strongly contribute to the amount of trouble you can get into. Wisdom will generally allow you to avoid common mistakes, and will often prevent you from the kind of weakness that pride (or a lack of humility) introduces.
A lack of humility, an inaccurate sense of who you are, will always provide an entity in the astral or spiritual planes an opportunity to attack. It will also always blind you. You will not understand the messages you receive, including those which signal the existence of those tiger traps.
A magician also contributes to any harm they take in the sense that a part of those confrontations concerns the will and belief of the magician. If a magician has reached the point, through the structured personal work and study necessary to have free will, that their belief is able to be under their control, the magician has reached the point where their will is useful in the astral or spiritual spaces. They can, in essence, prevent harm through the exercise of will and belief.
Their “no” actually does something, which is something an astral or spiritual entity will quickly discover when they attempt to overcome the magician. If a magician’s “no” is not effective, their will can and will overrule the magicians’ will, causing the magician to take harm using the magician’s will and belief.
The ability to have an effective “no” is not the common case, nor is it a state everyone can reach, even with a teacher and structured study. It comes rather later in the course of lives spent learning and requires enough force to do magic. Despite this, a teacher (if they have reached that point), can get you a lot closer than you will ever get alone.