1. Definition And Key Questions. Metaphysics, literally "beyond physics," is the branch of philosophy which studies the ultimate nature of existence. Sometimes the study is limited to being (ontology), sometimes to ultimate ends and final causes (teleology); sometimes the domains of cosmology, epistemology, psychology, and theology are crossed. The most sparkling metaphysical philosophies tend to be the classical ones: i.e., those of Parmenides, Plato, Aristotle, Plotinus, Aquinas (whose system was Aristotelian at its core), Spinoza, Leibnitz, and Kant. In the last couple centuries, philosophy has taken a decidedly naturalist and analytic course; it has been profoundly influenced by the new science. Questions About Being: What does it mean to be a "person"? What is the "I" that is "me"? Who am "I"? Do human beings have a soul? Is there any difference at all between a "soul" and ego-consciousness? Is human consciousness merely the by-product of matter? How can an incorporeal "something" be the result of molecular and atomic interactions? Does the soul ever function independently of the body? Are we "made up" of two substances -- e.g., mind and body, spirit and flesh -- or simply one (matter)? What happens to consciousness upon the expiration of the body? Will there be the slightest remembering, thinking, or feeling upon death? Teleological Questions. Is there a God? Is there an afterlife? Might there be an afterlife without a God? If God does exist, what is He/She/It like? Why did God create the universe? Why does anything at all exist? Can we -- will we -- ever know? Does life has a cosmic purpose or plan? If there is a divine plan, what is it? Was it ever revealed in human history? Will it ever be revealed in the future? Free Will And Determinism. Do human beings have "will"? Are we free to choose any course of action? When is our will free; when is it determined? If the will isn't free, can human beings ever be held accountable for their behavior? Do words like "ought" and "should" imply that the human will is free, as Kant believed? Time. Does time exist, or is it just an illusion? Does time consist of past, present, future? If so, why will the future (tomorrow) quickly become the past (yesterday)? If one thing becomes another, how can it have any meaning as an event x or a thing y? Did the universe ever have a beginning? Is time infinite? These are all just some of the many questions metaphysicians ponder.
2. Prevailing Views. Parmenides. Whole of his work not extant, but fragments exist, as well as numerous references to his ideas. One of Plato's later dialogues is titled "Parmenides"; in it, Parmenides challenges the theory of Forms. Parmenides put forth a monistic view of reality, emphasizing "the One". If all things are made of some basic stuff, he reasoned, there cannot be empty space. "Being is; non-being is not." Truth is static and unchanging and should be distinguished from the emphemeral reality of everyday life. Plato. Two realities: one material, which is the everyday world we experience and perceive (aka the sublunar world); the other is idealistic and transcendental, a perfect world of unchanging Forms or Ideas (the supralunar world). Human souls had a pre-life; incarnation is the process by which souls are collapsed into bodies and become veritable prisoners. Knowledge, Truth, Virtue, Justice are all "real," but as Ideas. The goal of life is to know the Truth, to purify the soul, to transcend ephemeral life. Philosophers need not fear death, says Plato: death by definition is the parting of soul and body, and the philosopher's soul is wise and good. Aristotle. God is the primum mobile, the first mover, the "uncaused cause" of the universe, but a being that does intervene in history. The divine substance, or essence, is a pure form. The only truly "real" things are individual substances ("this rock," "that man," etc.). Reality consists of form and matter. Form is the principle of actuality in something; matter is the principle of potentiality. The "form" of a person is his/her soul; the matter is the body. Four causes of all things: efficient, final, formal, and material. (Example: a can of gasoline exploding when a lit match is tossed into it. The can is the material cause; its position to the match is the formal, or necessary, cause; the falling match is the efficient cause; and the admixture of gas and oxygen is the final cause.). Plotinus. Ultimate reality is the "Ineffable One," the source of all being, truth, goodness, and beauty. The material universe is merely an emanation of this One. His views are uncannily similar to Plato's. There are successive levels of reality, the highest being the ideational One. According to Plotinus, the levels are the One, the Mind, the Soul, and the physical world, or nature. Human beings are souls "fallen" into matter. Communion with the Ineffable One is the highest good. Spinoza. Two modes which the human mind can grasp: thought and extension. God is "in" all things; the world, so to speak, is God's body. Each existent is a materialization of the divine. This doctrine is known as pantheism. The highest good in life is the intellectual love of God. Spinoza denied that there are mysterious forces at work in nature, what are sometimes referred to as "final causes". He also rejected the immortality of the soul and free will and was a devout determinist. Leibnitz. World consists of unique, indivisible, eternal substances, what he calls monads. Each monad is akin to a human soul; each is a "spiritual" substance. The "governing principle" of all monads is God. "Monads have no windows and no doors," Leibnitz famously said -- i.e., monads don't act externally on other monads. The world is harmonious, the best possible of all worlds, designed by God. Kant. Knowledge can't pass beyond the limits of everyday experience. The "thing-in-itself" cannot be known, only as a reference point in time and space. The existence of God is presupposed by art and ethics and religion. Kant endorsed the so-called "moral argument" for God's existence: moral laws have a governor, an author; the author is God. List Of Different "isms". Materialism: The view that only matter exists; emotions, sensations, dreams, hallucinations are seen as effects of a material process. Naturalism: The view that phenomena can be explained by reference to cause and effect and other "laws" of nature. It is vehemently opposed to theistic or literalist metaphysical views. Epiphenomenalism: The view that mental processes (thoughts, ideas, feelings) are the effects of physical/bodily processes; mind and body do not "interact"; there is rather a causal relationship between the two. Epiphenomenalism is a version of materialism. Occasionalism: The view that mind and body function independently, but that divine intercession allows mental events to be the "occasion" for different bodily movements. Pantheism: The doctrine that God inheres in all things; that the things of the world are manifestations, in some sense, of God. God, on this view, does not stand apart from, or outside of, the universe. Panentheism: The view that only one part or aspect of God inheres in the things of the world, but that God as Creator also transcends created being. So God is both "in" and "not in" existents. Logical Positivism: Denies the possibility of metaphysical knowledge; it sees metaphysical statements as meaningless, as linguistic sleights of hand (most famous exponent of this view is A.J. Ayer). Voluntaristic Idealism: The world is my idea of it. The object of perception is the appearance of a thing-in-itself. One's body is an objectification of one's Will. The Will is the dominant force in nature. This doctrine was propounded most famously by Schopenhauer. Solipsism: The belief that only I as subject exists; an opposing view is pluralism. Nihilism: The denial of moral truth, of fundamental religious claims, and of popular value systems in general. The view also that life has no aim or meaning, and that any such perceived meanings are constructions of the human will. The most famous philosophical exponent of this view was Friedrich Nietzsche.
See also A Glossary Of Terms.
Thomas Aquinas: Summa Theologica
Aristotle: Physics; Metaphysics
A.J. Ayer: Language, Truth, And Logic
F.H. Bradley: Appearance And Reality
Rudolph Carnap: Philosophy And Logical Syntax
R.G. Collingwood: An Essay On Metaphysics
Georg Friedrich Hegel: Phenomenology Of Mind
David Hume: A Treatise Of Human Nature
Immanuel Kant: Prolegomena To Every Future Metaphysics; Critique of Pure Reason
Gottfried Wilhelm Leibniz: The Monadology And Other Philosophical Writings
Arthur Lovejoy: The Great Chain of Being
Friedrich Nietzsche: The Will To Power
Plato: Phaedo; Parmenides; Timaeus
George Santayana: Realms of Being
Arthur Schopenhauer: World As Will And Idea
Baruch Spinoza: Ethics
Alfred North Whitehead: Science And The Modern World