The word “metaphysics” is one of the most misused terms in philosophy. In its ordinary usage, it refers to things like E.S.P., pyramid power, and channeling. But that is not what philosophers mean by the term. Metaphysics is the study of reality. Its subfield ontology examines what exists. Ontology asks, “What is the furniture of the universe?”, while metaphysics asks “What is the furniture of the universe and what do we know about its upholstery?” Ontological questions would include: Does God exist? Do other people exist? Metaphysical questions beyond ontology would include: Is there a difference between the mind and the brain? Is the world really in color or is that just a function of how we perceive it? Are humans free to choose our actions or is everything predetermined?
The central question of metaphysics is “How do I know that the real world resembles the world I perceive.” Look at a chair. What do you see? A chair. (Deep, I know. This is philosophy.) So, if one were to ask you if there really was a chair in front of you, you would certainly say, “Of course, I see that chair.” The question is, “Where is your vision of the chair?” It isn’t out there in the world. It is in your mind. The central question of metaphysics is “What justifies your move from the vision in your mind to a reality outside of your mind?” How do you know the world as you perceive it is the real world?
Immanuel Kant called the pictures in your mind the phenomena and the things in the real world outside of your mind the noumena. To use this new terminology, the central question of metaphysics is “How do we know that the noumena resembles the phenomena?”
You perceive things in your dreams, when you imagine, or when you have hallucinations. In these cases, there are phenomena – you do have images in your mind – but in these cases there is no reality to them. These images in the mind do not connect to anything outside of the mind. So, how do you know that the images in your mind do connect to something outside of your mind when you are perceiving normally?
You have experiences. That much you know. And if you have experiences, then you must exist. This is the point of René Descartes’ famous dictum “I think, therefore I am.” Descartes was trying to figure out if there was anything at all he could know with absolute certainty, anything he could not possibly doubt. The one thing he realized was absolutely certain was the metaphysical claim that “I exist.” How do you know this? Try to doubt it. Who is doubting this? I am. So, you must exist. To doubt is to think. To think is to do. And you cannot have doing without a doer.
But what kind of thing are you? Not the full you. All Descartes has given you is that you know you are because you act, you think. But thinking only requires a mind. So, all you know is that you exist as a thing that thinks, a disembodied floating thinking thing.
What about your body? Can we get there? Kant says we can’t (or “Can’t says we Kant,” one of the two). He argues that this is where the metaphysical questioning has to end. Try to go further and you run into contradictions.
But other philosophers disagree. (Yeah, surprising, I know.) Other philosophers have argued that we do know we have a body separate from the mind. Not only is it separate, it is a completely different kind of thing. Metaphysical dualism is the view that the world is made up of two kinds of completely different sorts of basic substance: mind or soul and body. Picture in your mind a burrito. Got it? Is it real? Yes and no. The idea is a real idea, but it is not a physical burrito. The idea is mind stuff where a physical burrito would be body stuff.
Metaphysical dualism is the common sense ontology. There are two kinds of things and humans are lucky to be comprised of both mind and body. The big problem with this common sense view is “the problem of interaction.” If mind and body are different kinds of things, they should not be able to affect one another. To move a chair, you have to push it. Physical action requires a physical force. You cannot move the chair by thinking at it. Yet, that seems to be what happens when you decide to raise your hand. The desire in your mind causes a physical occurrence. How does that happen? How does a mind, something without size, shape, or mass move something like your arm that has size, shape, and mass? In the other direction, what happens when you stub your toe? It hurts. There was a body to body interaction when your toe hit the chair leg, but how does a body to body interaction give rise to a mental state, pain? How could a purely material interaction cause a mind event? If you want to be a dualist – and lots of people do – then you need a good answer to this question.
But there aren’t any universally accepted good answers. So, many philosophers give up the common sense ontology of dualism. Metaphysical monism is the view that there is only one sort of substance.
Metaphysical monism comes in two varieties. Materialism is the view that the only sort of substance in reality is body, matter, physical stuff. If you think that all that exists are atoms, then you are a materialist. The difficult question for materialists is understanding consciousness, the nature of mind. It is demonstrable that there is a correlation between brain states and mind states. When you stub your toe, there is a portion of the brain that lights up. That section only lights up when your toe is in pain. The excited state of the brain, with certain neurons firing and certain neurochemicals released is the brain state. The experienced pain, the ouchie, is the mind state. These are correlated. There is no doubt that they always appear at the same time. But they certainly seem like different sorts of things. Materialists have to contend that either the brain state is the same exact thing as the mind state or that the mind state is somehow emerges from the brain state. Many philosophers hold this view and are working on this project.
The other sort of metaphysical monism is idealism, the view that there is no matter only mind. Some idealists argue that there is only one mind – the mind of God – and everything is some aspect of it. Others argue that there are many minds all having their own experiences and what the philosopher needs to do is to understand the nature of these experiences and what makes them up. Since Kant called these internal experiences “phenomena,” the philosophical movement that takes the central project of metaphysics as trying to make sense of the nature of these phenomena is called phenomenology.
This part of metaphysics we’ve been discussing, ontology, is figuring out the building blocks of reality. But another part tries to understand the nature of the stuff we all acknowledge exists. Many metaphysicians live for categories. They want to be able to differentiate the stuff that exists into distinct classes. That means coming up with criteria that distinguish one group of things from another. Some of these groups are going to be natural kinds, that is, groups of things in nature that belong together. Species, for example, are natural kind terms. A person and a box turtle belong to different natural groups. Artificial kinds are coherent groups of created things. To say 29 that there is a difference between one kind of thing and another is to draw a distinction. Drawing distinctions is a major move in philosophy because it allows you to explain why different things should be treated differently.
Drawing distinctions requires setting out conditions. Conditions come in two important types. Necessary conditions are those properties that something must have to be a member of the group. Having a pulse is a necessary condition for being a living human. No pulse, not a living human. A pulse is necessary, that is, it is needed.
Sufficient conditions are the properties that by themselves are enough to grant you membership in the group. Inheriting ten million dollars is sufficient to make someone a millionaire. By itself, that’ll do it. It is sufficient, that is, enough, to become a millionaire even though it is not necessary – you could win the lottery or build a company that you sell for over a million dollars.
Sufficient conditions are by themselves enough to put you in the group, although they are not the only way. Necessary conditions are needed to get in the group, everything in the group must have them, but they are not by themselves enough to be included in the group. It is a needed part, but not all you need.
When you have a set of conditions that are necessary and sufficient, we call that a definition. Definitions completely describe all and only the properties that makes something a member of the group. Notice that this is different from a dictionary definition. A dictionary definition is a description of how people ordinarily use a word in normal conversation. A philosophical definition is something more rigorous. Dictionary definitions are the result of lexicographers studying how the language is spoken and documenting that. Philosophical definitions are the result of philosophers trying to come up with clear, rigorous accounts that draw absolute lines, even if most people use the word differently (or, as philosophers call it, “wrong”).
In philosophy, a proposed definition is called a theory. We test theories against the world. If someone has a theory, it could go wrong in two ways. Their conditions might be too narrow, that is, there might be things that belong in the group that do not satisfy their conditions. Consider the classical definition of humans as “featherless bipeds,” that is, to be human is to have two feet and no feathers. If someone loses a leg in an accident, that person is still human, but does not satisfy the conditions.
“Featherless biped” is therefore too narrow of a theory to be a legitimate definition of the group “human.”
Alternatively, a theory can be too broad, that is, there are things that satisfy the conditions, but do not belong in the group. If I tried to define the notion of a chair as a thing people sit on, this would be too broad. We sit on things that are not chairs. We sit on the floor. The floor is not a chair. I would need additional necessary conditions to narrow down the group of things to have a successful definition.
In this part of metaphysics, the goal is to come up with a theory of some concept that is not too broad and is not too narrow. When you have that, you have a definition. We will look at attempts by philosophers to define the concept of humor. What is it for something to be an act of humor? What are the essential characteristics? Can there be a definition? Some argue yes, some argue no. Let’s see the grounds on which these cases are made.