For this I'm going to need you to scoot up your chairs and read this sentence closely - how do I move chairs across the globe with my mind? Imagine this: there's a blueprint someone has made for a specific type of chair that someone is destined to build to exact specifications one day. Did that chair start existing from the point the blueprint was finished, or when the blueprint was first used? As a little thought experiment I'd like to explore the possibility of that chair existing at some capacity from the finishing of the blueprint. 

During the process of ideation and creation of a blueprint and the idea preceding it, if one were to follow Newtonian principles, there is a consistent equal and opposite transaction between the corporeal materials the human brain exhausts and the noncorporeal things that the human brain produces. This noncorporeal phenomena has precedent in interacting with the corporeal at various capacities which are most notably expressed in the placebo and nocebo effects. Chemicals in the brain are released and physical phenomena can be felt such as pain or pleasure. 

If you are the ruler of a country 1,000 years ago and an idea in a book convinces you into thinking you have ingested poison that will kill you in ten days...you will take drastic measures with what you order others to do. You may start to feel lightheaded and ask your concubines to fan you while you're shouting to request a medical professional; you may make a drastic tactical move in the war of conquest you're foreseeing so that the war may be over by the point your seemingly incompetent next of kin takes the throne; you may unwittingly ingest a real poison to counteract the symptoms you are experiencing. Now, picture there was a very cunning person behind the scenes who surmised this would happen if you were to read a book that they gave you. They know that you are superstitious, know your drinking tastes, and noticed that something that you might come in contact with is described in the book as extremely poisonous. It could be anything, like a common spice coming in contact with an ale. 

This entire diatribe started with a little magic trick that, depending on a few factors, might have worked. One of those factors is a phenomena called 'credibility' where the more there is, the more verisimilitude my expressions carry. So long as there is a sufficient appearance of being true or real tied with a sufficient charismatic call to action then magic is viable. Given that credibility relative to a source varies from subject to subject, there is an indefinite list of variables that is infinitely impossible to quantify that are relative to the production of credibility from situation to situation. I'll give you one example: I am 21 years old and I have no college degree. I work as a janitor at a psych hospital. If one were to know only that about me before going into this diatribe then I'd only have an estimatably small portion of credibility. For the most part it's my relative anonymity online that people can project upon which allows me room to be credible if I play my cards right enough that you only know the good fractions of my general character. If I were to, say, go to college and get a master's degree then start working as a professor, then I'd likely gain an estimatably sizeable amount of credibility. 

One common trick that is found often among people with antisocial personality disorders who don't feel like playing the educational credibility route is, well, starting a cult. These people generally need to have a lot of narcissistic traits to their character to be able to convincingly get others to believe that they are an important voice in the grand scheme of things. For instance: a man who, normally is just a cable guy, posits that he is the son of God and is here to save humanity from damnation. If this man were to surround himself with followers that are convinced of his claim, then he, for all intensive purposes, has found a cheat code to attaining credibility. The existence of people using these strategies have the ironic effect of making it nigh impossible for a hypothetical true child of God to see it as a viable tactic to expose that notion if they were simply born as just another human with no super powers or anything, but that's a whole other can of worms. Either way, the more saturated in cult starters humanity becomes, the harder it will be to gain credibility from both having a genuine claim and faking it. That being said, cult leaders who have successfully convinced others of their claim have an abnormally potent level of credibility. It would be safe to consider this type of exercising magic to be the black magic counterpart.

I wish I could go more in depth but I have fifteen minutes before I have to walk to work.