Think of it as splitting events into 2 categories:
1. Events that can be controlled.
2. Events that cannot.
For events that cannot be controlled, they are further divided by asking, not what, but "who" is in control? I use that word specifically because it characterizes an inherent tendency in people to anthropomorphize the universe. That perception of control, in most people, is often described with words like "The Universe," "God," "The World," or even "Society."
Internal Locus: I observed a property of the universe.
External Locus: The universe revealed something to me.
Undefined: I happened to be in a position to observe something the universe did.
Internal Locus: I misplaced my car keys.
External Locus: I couldn't find my car keys.
Undefined: I couldn't remember where I put my car keys.
This is important because how we perceive phenomena and events influences how we understand and explain things.
For instance, "How does water know which direction to flow?"
Water doesn't "know" anything. It has no intelligence. It has no mechanism for even having an intellect. Water flows downhill because of gravity. More specifically, because gravity acts upon all things which have mass, and liquids generally flow more easily than solids in conditions commonly found on Earth.
This subject may seem trivial or extraneous, but this type of mindset noticeably affects how people perceive and understand Logic, Causality, Knowledge, Truth, Morality etc.
One last example:
External Locus: Allah revealed the writings of the Koran to Muhammed.
Internal Locus: Muhammed made it up, and attributed it to being inspired by God.
To say that the universe reveals things is to imply a motive, and also to imply that a certain occurrence was out of the ordinary, regardless of how we've observed the universe to normally behave. If your Locus of control is external, then when Logic is demonstrated to be applicable to the universe, you may be perceiving that as the Universe revealing Logic to you, which would necessitate an existence of Logic that is external, instead of simply perceiving Logic as a method of thinking that works because it is based on observed principles. This perception will affect how you reconcile the idea of Logic existing in the universe, regardless of the fact that it doesn't have any tangible existence. It won't make sense, because you've already perceived the idea of Logic as being something external to your conscious mind.
