What if there were no objective facts, no objective truth, only our belief in them? What if our consciousness itself is an unconscious invention, constructed out of logic and language? In this thought-provoking volume, Lynn Segal describes how the ideas of Heinz von Foerster compel us to explore the question "Do we discover the world or do we invent it?". He suggests that we must first know how we think before we can claim knowledge of the world. While Constructivism may seem relevant only to those in the cognitive sciences, it is, in fact, highly relevant to everyone. Paradoxically, grasping the limits of our own understanding can free us to live more creative and meaningful personal and professional lives.