I must Create a System or be enslav'd by another Man's.

Blake is saying that no one lives without a framework for making sense of the world, so the only real choice is whose framework it will be. If you don't shape your own way of seeing, judging and acting, you will inherit someone else's, and you will probably never notice the chains. The line is spoken by Los, the blacksmith-poet figure in Blake's long poem Jerusalem, who stands for the creative imagination. He refuses to be ruled by the rigid, mechanical picture of reality that Blake associated with thinkers like Newton and Locke.

Behind this is Blake's wider conviction that imagination is not decoration but the faculty by which we understand anything. He distrusted institutions and doctrines that ask people to hand over their judgment. "Creating a system" doesn't mean building a grand theory. It means taking responsibility for your own pattern of values and meaning.

Today, someone might apply this by noticing which rules already run their life. Say you follow a productivity method or a career script because everyone around you does. You could pause, keep the parts that truly serve you, and write your own simple principles: how you spend your mornings, what you won't trade for money, what counts as a good day. They may be borrowed in part, but now they are chosen.