Phil 101: Realism, Reduction, Error-Theory

The debate between dualists and materialists is an example of a more general kind of debate you often encounter in philosophy.

In a philosopher’s vocabulary, a realist about Xs is someone who believes that Xs really exist, that they aren’t mere fictions. Realists about Xs also think that Xs aren’t radically different from the sort of thing we thought they were all along.

For example, a realist about the external world is someone who believes that there really are chairs and tables and oaken chests; that these are real things in the world and that they’re not just ideas in our mind, or constructions out of our experiences. A realist about nations thinks that things like France and the United States really do exist. An opposing view would say that nations don’t really exist, or that they’re just a kind of “social construction” or fiction. That is a non-realist view about nations.

The issue of realism doesn’t just apply to things. It also applies to properties. For instance, I am a realist about wealth. I believe that some people really are rich, and other people really are poor. Being a realist means believing that people really do have those properties. It doesn’t mean you think that people who are rich will always be rich, or that you think they deserve to be rich, or anything like that. Realism about the property of being rich just says that there really is such a thing as being rich. Some people really do, as a matter of fact, and at some time, possess that property.

A reductionist about certain things or properties is someone who thinks that facts about those things or properties can be reduced to, or explained away in terms of, facts about something else. For instance, most of us believe that biology reduces to chemistry. There are no distinctive, brute biological facts. It’s really all just chemistry. Perhaps facts about nations can be reduced to facts about certain people, and their actions, and what laws they enact. Facts about wealth might also be reducible in a similar way.

If you think a notion is not reducible, but you believe that things of that sort still really exist, then you’ll say the notion is primitive or irreducible.

Sometimes reductionists count as realists, and sometimes they don’t. It depends on what they’re reducing things to. It’s hard to come up with any general rule that tells you for all cases whether a given reductionist is a realist or not. If you think that facts about tables reduce to facts about atoms and electrons, then philosophers will still count you as a realist about tables. If you think that facts about tables reduce to facts about our ideas and experiences, then you’re not a realist about tables. This is a reductionist view about tables, but since on this view, tables turn out to be radically different sorts of things than we ordinarily took them to be, we don’t count it as a realist view.

Another example I gave in class was where someone says that God reduces to feelings that people have. That would not be counted as a realist view about God.

So those are some kinds of non-realist view. Another non-realist view is what we call error-theory. Error-theorists about Xs simply say that there are no Xs. For instance:

There are no demons. Nor is there any such thing as “being cursed.” Anyone who thinks that there are demons, or that some people are “cursed,” is making an error.

That’s what an error-theorist about demons and the property of “being cursed” would say.

• Sometimes the error-theorists tell us that we ought to just eliminate the notion in question, and no longer talk about it. Other times they might say that the notion serves a useful practical function, and that we can retain it as a useful pretense, so long as we recognize that really there are no such things. For instance, some philosophers think that modern science has shown us that there is no such thing as color. On their view, there are photons and reflectance patterns and neurons firing in the brain, but there is no such thing as color. Most of these philosophers are perfectly happy to let Kodak and Fuji go on selling “color film.” They don’t say that we have to get rid of the word “color.” That word serves many useful functions. They just think that really, strictly speaking, we should recognize that there are only photons and neurons firing and so on, and no real colors.

The materialist says that facts about minds and about mental phenomena all reduce in some way to facts about the brain and other physical phenomena. As we said, some materialists may say that the mind is itself a material thing, for example the brain. But most will say that the mind isn’t a substance or thing. A person is a substance—a wholly physical substance, on the materialist’s view. And the materialist thinks that people do “have minds.” She’s a realist about the property of “having a mind.” She thinks that a person’s having a mind really reduces to certain physical facts about that person.