While in architecture school, the Lao Tsu quote above was a popular one because of the clear references to shaping space. The act of defining a space with a wall, ceiling, or floor creates a room, or void, that now has some use for an occupant.
Shaping people's perceptions is a similar exercise.
People seem to constantly try to define what they know. When you define something you do make it easier to see, But, you also run the risk of turning people away that don't cleanly fit into specific categories.
Working with people or issues that people can't define can be challenging. However, effectively serving others starts with stepping out of your comfort zone and doing what you don't know.
The space in between where people stand on a particular issue, for instance. Is where opportunity exists to create understanding or a new source of value. This gray area can be shaped and sculpted into something that solves some problem or meets a certain need.
Be careful with how things are defined because it affects how people use and perceive them.