The philosophical branch of metaphysics asks a number of crucial questions that all thoughtful people would do well to engage. Metaphysics is ultimately the study of reality and the nature of existence, and the more we know about reality the better it is for us. Below are several commonly employed terms which are helpful starting points for learning more about metaphysics and the kind of stuff philosophers write and dialogue on. This is also an invitation for further research, for nearly all of the below terms are still debated and discussed by philosophers.
Axiom – An axiom is a statement that is so well established that it is accepted without question. It does not rely on anything else in order to be valid, and it cannot be refuted given that any attempt to refute it requires the usage of the axiom in a premise. In other words, they are statements that one cannot deny without using them in his denial. For example, that I exist is an axiom for if I doubt that I exist then who is doing the doubting?
Consciousness – Views of consciousness differ between philosophers, however, a good definition is the ability for organisms to engage in introspection and extrospection. Introspection refers to the ability for an individual to access mental states within himself such as his thoughts, feelings, desires, and emotions. Extrospection is the individual’s ability to perceive objects, entities, and environments that exist external to his own mind.
Contradiction – According to the Law of Non-Contradiction two statements that contradict each other cannot be true, and it is a basic logical law that we all use in daily life. In fact, if one finds a contradiction in her thought or arguments then she must rethink her premises in order to avoid this error in logic.
Cosmogony – The branch of metaphysics that studies the beginning of the universe as well as the different parts that make up the universe. Cosmogony is important in the philosophy of religion, especially classical arguments for the existence of God from a first cause. Renowned philosopher William Lane Craig is arguably the world’s leading proponent of this through his formulation and defense of the Kalam Cosmological Argument.
Determinism (Hard) – The view that all actions and events are predetermined by genetics, environment, biochemical processes, and the laws of nature. This view denies that human beings make free choices despite the fact that they feel that they do. On this view free will is an illusion.
Existence – This subject of existence is a key area of focus in metaphysics. Existence postulates an objective reality (the world) in which human beings act as well as engage. Metaphysics examines this in terms of what it is, why it is the way it is, and what it means for human beings to exist within it. Existence is also an axiom. For example, any argument the individual makes about the non-existence of the world would assume that the world exists.
Free Will – The view that human beings are able to decide upon a course of action from among various alternatives. Many philosophers argue that the concept of free will entails moral responsibility for only if free will exists can human beings be fully responsible for their actions.
Identity – All entities (a person, a chair, or a cat) that exist have a particular identity. An identity consists of characteristics that make a specific entity that entity: a dog is furry, has legs, and a particular smell. Moreover, the Law of Identity says that an entity only has one identity: a dog is always a dog, and in no place can a dog also be a tree.
Laws of Logic – The Laws of Logic are universal laws that form the basis of discourse. There are three classic laws: the Law of Non-Contradiction, the Law of Excluded Middle, and the Law of Identity. These are realities in the world that human beings did not invent but rather discovered. They are also laws because they apply universally and therefore are absolute. For example, that a chair is not door (the Law of Identity) applies in Canada as well as in Australia.
Mind-Body Problem – The study of the relationship between the mind and body in human beings and animals. Theories and explanations accounting for the mind-body problem differ. For example, some theorists view the mind and the body as distinct entities that interact with each other. Other theorists view the mind as immaterial yet still dependent on the brain. Some have argued that the mind is proof of the supernatural or is best explained by the supernatural. Moreover, some have even denied that the mind-body dichotomy exists.
Mind, Philosophy of – The branch of philosophy that deals with mental and psychological phenomena, and includes the study of perception, consciousness, and mental functions. Theorists adopt several competing views, for example, dualism (the mind and body are separate from each other), monism (the mind and body are one), and idealism (that the mind is all that exists).
Mental Entity/States – This is a term that refers to mental states such as ideas, thoughts, and memories. These entities are not material, they have no physical parts and are not objects. For example, that I am thinking of table obviously does not mean that a table literally exists in my head. Rather, a mental state such as a thought could be described as immaterial information and content that is accessed and known by the individual thinking the thought.
Morality – The view that certain behaviours are good or bad, right or wrong. Philosophical views differ between philosophers. Some theorists, especially hard determinists and naturalists, deny that objective morality exists. By objective morality one means that certain acts are good or evil independent of how human beings view these acts (moral realism). For example, genocide would always be a moral evil even if every human being in the world believed that it was a moral good. By denying this view of morality a number of philosophers have little else than to hold to moral relativism by which human beings, societies, and cultures are the determinants of what constitutes moral behaviour as opposed to what doesn’t.
Properly Basic Belief – This is a belief that one holds to that is consistent with human experience and that is rational to hold to in the absence of a logical defeater. For example, that there exists an external world of physical objects independent of one’s mind is a properly basic belief that nearly all of us view as rational to belief, however, it remains a belief that can be doubted.
Substance – Many philosophers believe that what is “substantial” truly exists, that every substance has qualities, and that it stands in relation to other things. For example, a rock is a substance. It is hard, rough, and has sharp edges. The rock also 10 meters away from a tree, thus stands in relation to the tree.
Nothing – In the philosophical sense absolute nothingness refers to a total absence of anything such as space, matter, and even time. Nothing has no identity, characteristics, or causal power to bring anything into existence or bring about any change and effect. There is confusion for many when it comes to how physicists use the term. When a physicist uses the term “nothing” he does not mean it in the sense absolute nothingness as described. Rather, he is in fact often referring to a quantum vacuum which is a specific thing with certain characteristics.
Ontology – The philosophical study of the nature of being, properties, and the relations between entities. For example, what is the relationship between human beings and time, or the relationship between physical and immaterial entities? Does God exist? And if God exists what is his nature and relation to human beings?