Posted per suggestion by RamanaJi.The three major metaphysical philosophies1.2. Materialism (pure objectivity): The philosophy that all is matter, or at least, all is governed by physical law
The earliest well-articulated philosophy of materialism was that of Democritus (Greek philosopher, c. 460 - c. 370 BC). He postulated a world made up entirely of hard, invisible particles called atoms. These atoms had shape, mass and motion, but had no other qualities, such as color or flavor. These latter qualities were considered to be subjective and were supplied by the observer, who also was considered to be comprised of atoms.
Little further progress was made with materialist philosophy until after the Protestant Reformation, which was initiated in Germany in the 1520s by the Augustinian monk, Martin Luther (1483 - 1546). This stimulated such ferment that the Roman Catholic order of the time was overturned and was replaced by the new religious, political, and scientific orders of the 17th century. Atomism was then revived in the 1640s by French scientist and Catholic priest, Pierre Gassendi (1592 - 1655), who sought to combine the theory with Catholic doctrine. However, beginning in the 1640s, the liberation of science from all Church authority by the philosophy of Cartesian dualism (see next section) and the subsequent enormous scientific advances of the 19th and 20th centuries solidified the authority of the materialists, and materialism became the dominant philosophy of the Western world.
Even those who claim to hold to philosophies other than materialism are influenced by it, perhaps in ways they are completely unaware of. Its fundamental principle is that matter and energy are primary and all else is secondary in the sense that all else is derived from, or is an outgrowth of, matter and energy. Since the advent of quantum theory in the 1920s and its fundamental questions about the nature of matter, this philosophy has sometimes been broadened to state that physical law rather than matter and energy is primary, i.e., everything can be explained and understood in terms of physical law. This is called scientism, or scientific materialism.
Of course, this immediately begs the question, what is physical law? One could say that physical law includes all of the laws of reality, in which case the question becomes meaningless. For our purposes, we shall restrict the definition of physical law to those laws recognized to be part of physics. Physics we shall understand to be the study of the fundamental laws that govern the external, objective reality that was defined in the previous section. Therefore, we shall understand materialism to be the philosophy that external, objective reality is primary, and everything else, such as all mental phenomena, are derived from, or are effects of, such reality.
The widespread belief in materialism has profound effects in our lives and in our society. If we believe this way, we must conclude that everything, including ourselves and all of life, is governed completely by physical law. Physical law is the only law governing our desires, our hopes, our ethics, our goals, and our destinies. Matter and energy are our primary focus, the object of all of our desires and ambitions. Specifically, this means that our lives are focused on acquiring material goods (including bodies), or at least rearranging or exchanging them, in order to produce the maximum material satisfaction and pleasure. We expend all of our energy in this quest for there can be no other goal. And in all of this, we have no choice because we are totally governed by physical law. We may feel trapped by these beliefs and desires, but we cannot shake them. They totally dominate us.A succinct, personalized, summary statement of materialist philosophy is, “I am a body.” 1.3. Cartesian dualism (objectivity plus subjectivity): The philosophy that both matter and mind are primary and irreducible
This philosophy was first propounded by René Descartes (French scientist and philosopher, 1596 - 1650) in 1641. It states that mind and matter (or the mental and the physical) are two separate and independent substances. Human beings (but not animals, according to Descartes) are composed of both substances. A mind is a conscious, thinking entity, i.e., it understands, wills, senses, and imagines. A body is an object that has physical size, i.e., it exists in physical space. Minds do not have physical size (hence do not exist in physical space) and are indivisible, while bodies are infinitely divisible (in Descartes’ philosophy). Descartes initially wanted to limit his premises only to those that were indisputable; hence his famous premise “I think, therefore I am.” The “I” in this statement is the mind and, since it does not exist in physical space, it can in principle survive the death of the physical body. Even though Descartes thought that mind and body existed independently of each other, he thought that mind could act on body.The succinct, personalized, summary statement of dualism is, “I am a mind, and I have a body.”1.4. Idealism (pure subjectivity): The philosophy that consciousness is all and all is consciousness
Idealism states that mind or consciousness constitutes the fundamental reality, or is primary. Some versions of idealism admit the independent existence of material objects, others deny that material objects exist independently of human perception.
Anaximander (Greek philosopher, c. 611 BC - c. 547 BC) may have been the first idealist philosopher. Only one fragment of his writing has been preserved but he seems to have thought that the original and primary substance (which could be consciousness) is a boundless
something from which all things arise and to which they all return. He was struck by the fact that the world presents us with a series of opposites, of which the most primary are hot and cold, wet and dry. He thought of these opposites as being "separated out" from a substance which was originally undifferentiated.
Plato (Greek philosopher, c. 428 BC - c. 348 BC) is often considered the first idealist philosopher, chiefly because of his metaphysical doctrine of Forms. Plato considered the universal Idea or Form, sometimes called an archetype—for example, redness or goodness—to be more real than a particular expression of the form—a red object or a good deed. According to Plato, the world of changing experience is unreal, and the Idea or Form—which does not change and which can be known only by reason—constitutes true reality. Plato did not recognize mystical experience as a route to true reality, only reason.
Idealism was first expounded by Plato in his cave allegory in The Republic (c. 360 BC) (see, e.g., Julia Annas, An Introduction to Plato’s Republic, 1981, p. 252). The cave is a metaphor for the mind. Prisoners are in an underground cave with a fire behind them, bound so they can see only the shadows on the wall in front of them, cast by puppets manipulated behind them. They think that this is all there is to see; if released from their bonds and forced to turn around to the fire and the puppets, they become bewildered and are happier left in their original state. They are even angry with anyone who tries to tell them how pitiful their position is. Only a few can bear to realize that the shadows are only shadows cast by the puppets; and they begin the journey of liberation that leads past the fire and right out of the cave into the real world. At first they are dazzled there, and can bear to see real objects only in reflection and indirectly, but then they can look at them directly in the light of the sun, and can even look at the sun itself.
This allegory is related to idealism in the following way. The cave is the mind. The shadows of the puppets that the prisoners are watching represent their taking over, in unreflective fashion, the second-hand opinions and beliefs that are given to them by parents, society, and religion. The puppets themselves represent the mechanical, unreasoning minds of the prisoners. The light of the fire within the cave provides only partial, distorted illumination from the imprisoned intellects. Liberation begins when the few who turn around get up and go out of the cave. Outside of the cave, the real objects (the Forms) are those in the transcendental realm. In order to see them, the light of the sun, which represents pure reason, is necessary. A similar allegory using today’s symbols would replace the cave with a movie theater, the shadows with the pictures on the screen, the puppets with the film, and the fire with the projector light. The sun is outside, and we must leave the theater to see its light (we must leave the mind).
The next major idealist philosopher was Plotinus (204/5 – 270 AD), who is generally regarded as the founder of Neoplatonism. He was one of the most influential philosophers in antiquity after Plato and Aristotle (who was primarily a philosopher of politics, ethics, and nature). The term "Neoplatonism" is an invention of early 19th century philosophers and was intended to indicate that Plotinus initiated a new phase in the development of the Platonic tradition. The (greatly simplified) basic principles of Neoplatonism are 1) The One (nondual Reality), which is the first principle of all. It is both self-caused and the cause of all dualistic concepts. 2) Intellect, which works with dualistic concepts that are derived from Plato's Forms. 3) Soul, which is the principle of desire for external objects. These principles are both ultimate ontological realities and explanatory principles.
The eighteenth century British philosopher George Berkeley (1685 - 1753) was one of the major exponents of idealism. He denied the existence of material substance (calling his philosophy immaterialism), and held that the universe consists of God, which is the infinite spirit; of finite spirits including human beings; of ideas that exist only in the minds of spirits; and of nothing else. According to Berkeley, spirits are able to perceive ideas but ideas are inert, without any power to perceive. His most characteristic philosophical doctrine is summarized in the expression "to be is to be perceived." In other words, to say that a material object exists is to say that the idea of it is perceived by a spirit. Since Berkeley assumed that material objects exist without human spirits to perceive them, the mind that perceives them must be divine rather than human.
The German philosopher Immanuel Kant (1724 - 1804) expounded a form of idealism that he called transcendental idealism. He believed that there is a reality that is independent of human minds (the noumenon, or thing-in-itself), but that is forever unknowable to us. All of our experience, including the experience of our empirical selves (the phenomenon, or thing-as-it-appears), depends on the activity of a transcendental self, also of which we can know nothing.
Georg Wilhelm Friedrich Hegel, also a German philosopher (1770 - 1831), built on the idealist philosophy of Kant, and called his system absolute idealism. He believed that reality is Absolute Mind, Reason, or Spirit. Absolute Mind is universal, while each individual mind is an aspect of it, as is the consciousness and rational activity of each person. Absolute Mind continually develops itself in its quest for its own unification and actualization. For this purpose, it manifests itself as the subjective consciousness of the individual, who undergoes a rational process of development from a purely materialistic and self-centered state to a universal and rational consciousness. In this process, the individual passes through several phases--family, society, state--each of which represents a move from individualism to unity. Human history in general is the progressive movement from bondage to freedom. Such freedom is achieved only as the separate desires of the individual are overcome and integrated into the unified system of the state, in which the will of the individual is replaced by the will of all.
The forms of idealism described above were all formulated by Western philosophers, who almost exclusively depended on rational thought to develop their philosophies. They scarcely took account of the many forms of Eastern philosophy, which are heavily dependent on mystical experience. Furthermore, there was very little recognition of the theories and knowledge that science was developing from the 17th century on. http://faculty.virginia.edu/consciousne ... usness.pdf