A City Guide To Yongjing for They help us produce clearly focused mental views. We might define a theory as a cognitive scheme or conceptual system that brings a part of the world into clearer focus and allows it to be better understood. Most of us can see the world quite well without the artificial lenses found in telescopes, microscopes, or even eyeglasses. Our unaided vision suffices. Likewise, most of us can get along quite well without engaging in formal theorizing. Our unaided intellect, common sense, and traditional cultural viewpoints prove adequate. Nevertheless, like the lenses we make out of glass or plastic to see more clearly, the theories we fashion out of concepts allow us to understand the world more thoroughly and profoundly. A City Guide To Yongjing 2016.