When I was 19 years old, both of my parents died in the same year; my mom of cancer and my dad in a car accident. Through the next two or three years and a series of bad decisions - all my own, I might add - I ended up literally homeless, before that was even a word. I even slept occasionally under a pier on the Gulf Coast.
Curiously, a principle affects your life whether you are aware of it or not. For instance, the principle of gravity was working long before the apple ever fell on Newton's head. But once it did, and he understood it, then we as a society were free to harness this principle to create, among other things, airline flight.