Thought can refer to the ideas or arrangements of ideas that result from thinking, the act of producing thoughts, or the process of producing thoughts. Although thought is a fundamental human activity familiar to everyone, there is no generally accepted agreement as to what thought is or how it is created. Somehow, thoughts arise in the mind from the product of subconscious brain processing. Because thought underlies many human actions and interactions, understanding its physical and metaphysical origins, processes, and effects has been a longstanding goal of many academic disciplines including psychology, neuroscience, philosophy, artificial intelligence, biology, sociology and cognitive science. Thinking allows humans to make sense of, interpret, represent or model the world they experience, and to make predictions about that world. It is therefore helpful to an organism with needs, objectives, and desires as it makes plans or otherwise attempts to accomplish those goals. This books discusses the categories of the human thought process.