The best way to approach an understanding of metaphysics is with the use of an example, so let’s begin by looking at the kind of problem with which the Greeks were concerned. They had what one might call a crude system of beliefs. They attempted to explain the workings of the universe in terms of four fundamental elements: air, fire, earth, and water. Briefly explained, according to the Greeks, the planet Earth was at the center of the universe, and the heavens rotated around Earth. The elements of water and earth found their natural place on the planet Earth and were thought to “fall” to Earth. The elements of air and fire naturally rose to the heavens.
The primary question that the early metaphysicians asked was “are these four elements really the most fundamental things, or does some other thing exist beneath what is apparent and give rise to these four elements?”
The metaphysicians divided into two camps on the issue: those who argued that there could only be one “real” thing (monists) and those who argued that we needed more than one thing to account for
those things in the universe that we knew of (pluralists). The Greeks were asking “what is the true nature of what exists?
Can the things that we observe in the world be explained by one entity that underlies the four entities that we observe, or are the four categories of air, fire, earth, and water ultimately fundamental in themselves?”
Today, we have a more sophisticated scientific view, but we still have similar metaphysical problems. We have discovered that air, fire, earth, and water are all made of the same things (i.e., protons, neutrons, and electrons). Protons and neutrons, it turns out, are made of the same one thing — quarks — so some believe that the universe is made up of quarks and electrons.
Others argue that along with these physical objects, we have to include mental phenomena as objects of the universe. These are all different forms of pluralism. The monists would still argue that, ultimately, there are only physical objects and that one day, they will all be reducible to some fundamental thing and that mental things would be accounted for in this reductionism.
The metaphysician, then, is trying to account for all the current scientific knowledge, but in a broader context. Not only does he deal with science but anything else that may be known or believed about the universe. He can only function in rather vague terms but still seeks some kind of explanation for the most fundamental or general characteristics of the universe, and his work encompasses everything from matter to minds to God or other things that the metaphysical system under development may require.
Many systems have been developed over the last two thousand years, a few of which you might find on this blog. Though the speculations of the metaphysicians hold some interest, by no means is there any general agreement as to which set of speculations should be held up as the one true picture of the universe. Every school of thought within metaphysics can produce what appear to be convincing arguments against other systems of thinking; yet, they still remain unable to produce a completely infallible justification of their own views. And some philosophers have argued that metaphysics is a worthless exercise in and of itself, that due to basic limitations in our abilities as humans, the entire metaphysical enterprise is doomed to failure.