The word ‘metaphysics’ has its origin in the Greek language and is quite old, as Roger Hancock writes:
The word metaphysics derives from the Greek meta ta physika (literally, “after the things of nature”), an expression used by Hellenistic and later commentators to refer to Aristotle’s untitled group of texts that we still call the Metaphysics. Aristotle himself called the subject of these texts first philosophy, theology, or sometimes wisdom; the phrase ta meta ta physika biblia (“the books after the books on nature”) is not used by Aristotle himself and was apparently introduced by the editors (traditionally by Andronicus of Rhodes in the first century B.C.) who classified and cataloged his works.
One aspect of metaphysics is that it deals with things that are not directly known or perceived by the five senses (sight, hearing, taste, smell, touch). By contrast, physics deals with things that can be detected by those five senses. Newtonian physics deals with falling objects, accelerating object, etc., which can be rocks or automobiles or planets, all of which can be discerned by the five senses.
Even relativistics physics, subatomic physics, and quantum physics can be verified by the senses, although not directly. Roger Hancock continues:
Later, classical and medieval philosophers took this title to mean that the subjects discussed in the Metaphysics came “after the things of nature” because they were further removed from sense perception and, therefore, more difficult to understand; they used Aristotle’s frequent contrast of things “prior and better known to us” with things “prior and better known in themselves” to explain why the treatises on first philosophy should come “after the books on physics.” In medieval and modern philosophy “metaphysics” has also been taken to mean the study of things transcending nature — that is, existing separately from nature and having more intrinsic reality and value than the things of nature — giving meta a philosophical meaning it did not have in classical Greek.
Metaphysics is in one way or another dualistic, because it supposes two levels of reality: a physical dimension and a non-physical dimension. Sometimes, metaphysicians are tempted to ascribe more importance, more value, or more reality to one of those levels over the other. Other metaphysicians are content to allow both levels to exist side-by-side as equals.
If metaphysics is the study of things that can’t be perceived by the five senses, then the question arises: How does one learn about those things?
Immanuel Kant (1724 - 1804) distinguishes between two types of knowledge: a prior and a posteriori. The phrase a priori means “from before” in Latin, and refers to knowledge that is gained prior to the experiences gained from the five senses. For example, arithmetic is considered an a priori body of knowledge, because without sight, hearing, smell, taste, and touch, it is still possible to learn that 7 + 5 = 12. On the other hand, botany would be an a posteriori body of knowledge, because it is necessary to see and touch and smell and taste plants in order to know them.
Especially since Immanuel Kant metaphysics has often meant a priori speculation on questions that cannot be answered by scientific observation and experiment. Popularly, “metaphysics” has meant anything abstruse and highly theoretical — a common eighteenth-century usage illustrated by David Hume’s occasional use of metaphysical to mean “excessively subtle.”
In non-philosophical and non-academic usages, the word ‘metaphysics’ is used to deal with a variety of things, from serious spirituality to the quackery of reading tarot cards. It is necessary to distinguish between such popular usages on the one hand, and other the other hand, usages which are philosophical and academic.
The term has also been popularly associated with the spiritual, the religious, and even the occult. In modern philosophical usage metaphysics refers generally to the field of philosophy dealing with questions about the kinds of things there are and their modes of being.
Within metaphysics, the subdiscipline of ontology deals with questions about different kinds of being, and about which things exist and which ones don’t.
Upon reflection, things which cannot be discerned by the five senses are usually thought to be things which are composed of matter or energy or some mixture of the two. If one were to take the universe as it is, and remove all matter and energy, then whatever would remain would be metaphysical things.
Further analysis of these concepts yields the conclusion that metaphysical things are outside of space and time. Things often thought to be metaphysical are minds, memories, ideas, numbers, and shapes.
To better understand, it can be helpful to examine these things in pairs: A brain is a physical thing; a mind is a metaphysical thing. A numeral, which can be seen or heard, is a physical thing; a number is a metaphysical thing.
Blue paint, blue ink, blue cars, and blue jeans are physical things; the color blue by itself is a metaphysical thing.
The discipline of metaphysics borders on, and overlaps slightly with, some other subdisciplines within philosophy. Epistemology is the study of how, not what, can be known; to ask about how metaphysical things are known is to be on the borderline between metaphysics and epistemology.
Likewise, to ask about the existence of numbers is to be on the borderline between metaphysics and the philosophy of mathematics.
Its subject matter includes the concepts of existence, thing, property, event; the distinctions between particulars and universals, individuals and classes; the nature of relations, change, causation; and the nature of mind, matter, space, and time. In the eighteenth and nineteenth centuries metaphysics was used broadly to include questions about the reality of the external world, the existence of other minds, the possibility of a priori knowledge, and the nature of sensation, memory, abstraction, and so on. In present usage these questions are included in the study of epistemology.
The field of metaphysics has a long and varied history. Most of those who are routinely listed as significant philosophers engaged in metaphysical thought and left their marks on the field of metaphysics.
