Thought experiments are devices of the imagination used to investigate the nature of things. They are used for diverse reasons in a variety of areas, including economics, history, mathematics, philosophy, and the sciences, especially physics. Most often thought experiments are communicated in narrative form, frequently with diagrams. Thought experiments should be distinguished from thinking about experiments, from merely imagining any experiments to be conducted outside the imagination, and from psychological experiments with thoughts. They should also be distinguished from counterfactual reasoning in general, as they seem to require an experimental element, which seems to explain the impression that something is experienced in a thought experiment. In other words, though many call any counter-factual or hypothetical situation a thought experiment, this seems too encompassing. It seems right to demand that they also be visualized (or perhaps smelled, tasted, heard, touched); there should be something experimental about a thought experiment.
From Thales, who is often considered the first Western philosopher, to the Stoics and Skeptics, ancient Greek philosophy opened the doors to a particular way of thinking that provided the roots for the Western intellectual tradition. Here, there is often an explicit preference for the life of reason and rational thought. We find proto-scientific explanations of the natural world in the Milesian thinkers, and we hear Democritus posit atoms—indivisible and invisible units—as the basic stuff of all matter. With Socrates comes a sustained inquiry into ethical matters—an orientation towards human living and the best life for human beings. With Plato comes one of the most creative and flexible ways of doing philosophy, which some have since attempted to imitate by writing philosophical dialogues covering topics still of interest today in ethics, political thought, metaphysics, and epistemology. Plato’s student, Aristotle, was one of the most prolific of ancient authors. He wrote treatises on each of these topics, as well as on the investigation of the natural world, including the composition of animals. The Hellenists—Epicurus, the Cynics, the Stoics, and the Skeptics—developed schools or movements devoted to distinct philosophical lifestyles, each with reason at its foundation.
The concept of history plays a fundamental role in human thought. It invokes notions of human agency, change, the role of material circumstances in human affairs, and the putative meaning of historical events. It raises the possibility of “learning from history.” And it suggests the possibility of better understanding ourselves in the present, by understanding the forces, choices, and circumstances that brought us to our current situation. It is therefore unsurprising that philosophers have sometimes turned their attention to efforts to examine history itself and the nature of historical knowledge. These reflections can be grouped together into a body of work called “philosophy of history.” This work is heterogeneous, comprising analyses and arguments of idealists, positivists, logicians, theologians, and others, and moving back and forth over the divides between European and Anglo-American philosophy, and between hermeneutics and positivism.
Aristotle was the first person to investigate the patterns and processing of reason. He discovered (some would say invented) logic. For that alone, he counts high in the pantheon of the most influential people in history. Logic provides the basis for proof and demonstration using natural language. Prior to Aristotle, mathematicians had shown arithmetic and geometrical means to proof. It was the power of such abstract proofs that led Plato to place an inscription over the front gate of the Academy reading; "Let no one enter who is not a geometer." From this background, Aristotle extended the formal study of reasoned proof to a method that applies formal analysis to real human language. Philosophy, science, and technology have followed the path pioneered by Aristotle ever since.
Aristotle wrote several extensive works on logic, which taken together are known as The Organon or the instrument, by which which he meant that logic is an instrument for advancing knowledge.
Aristotle was not merely pointing out ways that people should think; he was describing the fundamental principles by which thought can occur at all. At this foundation he marked three laws of thought, which remain basic in logic to the present.
“Africana philosophy” is the name for an emergent and still developing field of ideas and idea-spaces, intellectual endeavors, discourses, and discursive networks within and beyond academic philosophy that was recognized as such by national and international organizations of professional philosophers, including the American Philosophical Association, starting in the 1980s. Thus, the name does not refer to a particular philosophy, philosophical system, method, or tradition. Rather, Africana philosophy is a third-order, metaphilosophical, umbrella-concept used to bring organizing oversight to various efforts of philosophizing—that is, activities of reflective, critical thinking and articulation and aesthetic expression—engaged in by persons and peoples African and of African descent who were and are indigenous residents of continental Africa and residents of the many African Diasporas worldwide. In all cases the point of much of the philosophizings has been to confer meaningful orderings on individual and shared living and on natural and social worlds while resolving recurrent, emergent, and radically disruptive challenges to existence so as to survive, endure, and flourish across successive generations.