All thinking is a process of identification and integration. Man perceives a blob of color; by integrating the evidence of his sight and his touch, he learns to identify it as a solid object; he learns to identify the object as a table; he learns that the table is made of wood; he learns that the wood consists of cells, that the cells consist of molecules, that the molecules consist of atoms. All through this process, the work of his mind consists of answers to a single question: What is it? His means to establish the truth of his answers is logic, and logic rests on the axiom that existence exists. Logic is the art of non-contradictory identification. A contradiction cannot exist. An atom is itself, and so is the universe; neither can contradict its own identity; nor can a part contradict the whole. No concept man forms is valid unless he integrates it without contradiction into the total sum of his knowledge. To arrive at a contradiction is to confess an error in one’s thinking; to maintain a contradiction is to abdicate one’s mind and to evict oneself from the realm of reality.