Pragmatism is about interpreting the world through the lens of cause and effect. By observing the effect of an action on you the effected thing is observed more clearly. To put it another way, by interacting with reality and observing how that changes you reality can be better understood. Thus the world can be understood through the narrow lens of personal experience even though the world is far vaster than that. In fact, the only existent aspect of anything lies in it's response to your presence, perception and projection.