Do Mental States Exist?

There are some, not many, philosophers who argue that there are no mental states – i.e. no thoughts, feelings, dreams, emotions, perceptions, intentions, etc. These philosophers are called eliminativists and their view is called eliminativism. To put it mildly, eliminativism is not a common-sense view. In fact, some have called it a crazy view. It’s clearly a radical view as it challenges a fundamental way we think of ourselves. The following views about mental states, which are taken for granted by most people, would all be false if eliminativism is true:

• Mental states play a causal role in behavior.
• Animals have mental states.
• You can only experience your own mental states.
• You can know about the contents of your own mental states
• There are similarities and differences between people’s mental states.
• Mental states are related to what’s going on in the brain.
• The quality of an individual’s life depends on his or her mental states.
• The morality of actions depend on mental states.

Another implication of eliminativism, albeit not necessarily a negative one, is that many philosophical problems in philosophy of mind would be rendered moot. If there are no mental states, then there wouldn’t be any question about…

• what the objects of mental states are – whether they are sense-data or objects in the world.
• whether mental states belong to a non-physical substance.
• how mental states are related to what’s going on in the brain.
• how could we know about the mental states of others.
• whether we have any mental states, such as higher-order mental states, that animals do not have.
• whether computers could have mental states.
• whether a person’s actions are free if they are caused by mental states.

Eliminativists belong to a long tradition of philosophers who have denied the existence of one thing or another that many people have taken for granted. In previous lectures, we’ve discussed some of these philosophers, such as those who have denied non-physical substances and those who have denied the existence of free will. Some of you may belong to this tradition if you deny the existence of God. But even if you believe in the existence of non-physical substances or free will or God, you probably aren’t as confident about whether these things exist as you are about whether your mental states exist. You may even be like some philosophers who are more confident that your mental states exist than anything else in the universe exists. The 17th century French philosopher Rene Descartes, the philosopher who believed that mental states are states of a non-physical substance, was one such philosopher. He argued that the existence of everything in the physical world, such as tables and trees and planets and brains, could be doubted because he thought he could be dreaming these things or an all-powerful evil Demon could be deceiving him into thinking that they were existing. But he didn’t think he could doubt the contents of his own mind. He was certain of what he was thinking and perceiving and feeling. If eliminativism is true, then Descartes’ view is false; if there are no mental states, then one cannot have any doubts and there would be no contents of mental states to doubt.

If eliminativism is true, then how can anyone believe eliminativism? It is contradictory for an eliminativist to say that he believes eliminativism, since eliminativism denies the existence of beliefs. However, it doesn’t follow that eliminativism is a self-contradictory view. While some philosophers have argued that eliminativism is self-contradictory, it’s not obvious that it is. After all, it’s reasonable to believe that there were no mental states, at least on Earth, about a billion years ago. So this gives us reason to believe that it’s possible there are no mental states. Of course, eliminativism is saying something stronger than saying there are no mental states is not self-contradictory. Eliminativism is saying there are no actual mental states. This means that mental terms like “thought” and “emotion” and “dream” and “mental state” have some sort of meaning, but they do not refer to anything. These terms are like the term “witch,” a term that means an evil woman who has magic powers, but doesn’t refer to anything. To say that the term “witch” and the term “mental state” don’t refer to anything is just another way of saying that there are neither witches nor mental states.

You might wonder what explanation could be given for people’s behavior if they have no mental states. For example, suppose Tom goes to the store and comes home with some ice cream. What is the explanation for this piece of behavior? One explanation is that Tom went to the store because he wanted some ice cream. This explanation of Tom’s going to the store ascribes a mental state to him (his desire for some ice cream), which plays some causal role in his behavior. But, if there are no mental states, then what is the explanation for Tom’s behavior? The eliminativist’s answer appeals to something going on in Tom’s brain, not his mind. The eliminativist acknowledges that we currently use mental terms like “desire” to explain behavior. But he asserts that these mental state explanations for behavior will eventually be replaced with explanations that appeal to brain states. His reason is that our commonsense statements about the mind constitute a primitive theory, sometimes called “folk psychology,” and this theory is simply false. Let me explain.

Just about everyone claims to know a large number of common-sense generalizations about mental states, such as how they connect with other mental states, with external circumstances, and with behaviors. Paul Churchland, a famous eliminativist, gives a few examples of these common-sense generalizations:

• Persons tend to feel pain at points of recent bodily damage.
• Persons denied fluids for some time tend to feel thirst.
• Persons in pain tend to want to relieve that pain.
• Persons who feel thirst tend to desire drinkable fluids.
• Persons who are angry tend o be impatient.
• Persons who feel a sudden sharp pain end to wince.
• Persons who are angry tend to frown.
• Persons who want that P, and believe that Q would be sufficient to bring about P, and have no conflicting wants or preferred strategies, will try to bring it about that Q. [P. Churchland. “Matter and Consciousness” 1988, 58-59.]

The eliminativist claims that all the common-sense generalizations about mental states together constitute a theory, a “folk psychology,“ which explains peoples’ behavior, including their judgments about their own mental states. It’s a theory we learn from our parents when we were young and were learning how to speak. As with any theory, the entities postulated by the theory (in this case the mental states) can only be justified to the extent that the theory is true. The problem, according to the eliminativist, is that folk psychology is a false theory. Thus our commonsense statements about mental states, including the statement that mental states exist, are all false.

Let us put the eliminativist’s argument into standard form so it’s easier to understand.

1. Folk psychology is a common-sense theory that posits the existence of mental states and that we use to explain the behavior of people.
2. Folk psychology is a false theory.
3. So, mental states do not exist.

To say that a theory posits entities, such as mental states, is to say that the theory assumes the existence of entities. Mental states are posited because they cannot be observed, as behavior can be observed. It’s important to note that the eliminativist is not arguing that mental states do not exist because they cannot be observed. Things can exist even though they cannot be observed, according to the eliminativist. Consider atoms, for example. Eliminativists agree with the scientists that atoms exist even though they cannot be observed. Here is their argument in standard form.

1. Atomic theory is a scientific theory that posits the existence of atoms and that we use to explain many of the properties of matter.
2. Atomic theory is a true theory.
3. So, atoms exist.

This pattern of reasoning is one that Gregor Mendel in the 19th century used to discover genes, the particles in living things that allow parents to transmit characteristics to offspring in reproduction. We now have the technology to observe genes, but when they were first discovered by Mendel they couldn’t be observed. Mendel conducted breeding experiments with pea plants and he noticed that when certain sorts of these pea plants were crossed, their offspring exhibited characteristics in certain proportions. He then offered a theory to explain why this was the case. His theory posited these particles (we call genes) that determine the observed characteristics. Genetic theory is a powerful theory in terms of what it can explain and predict, and so many people have now claim that genes actually exist.

Both atomic theory and gene theory are recognized today as good theories because they explain a lot of phenomena; so we have reason to believe in the theoretical entities that they postulate, namely atoms and genes. But not all theories are good. If a theory is bad at explaining what it’s intended to explain, or there is a better theory, there is reason to deny the existence of the entities the theory posits. We know, for example, that demon theory is a bad theory for explaining disease, because, unlike germ theory, it does not explain certain facts about disease, such as how it spreads and how it can be treated. So we have reason to deny the existence of demons because demon theory is a bad theory. But is folk psychology a bad theory like demon theory? Churchland gives several reasons for why it is. Let’s just consider two of these reasons.

Reason 1: If a theory is any good, then, according to Churchland, it must have widespread explanatory power.  That is, it should be able to explain the subject matter it pertains to. While folk psychology seems to be a good theory at explaining certain things of its subject matter, such as why Tom went to the store or why Mary shouted when she put her hand on the hot stove, it fails to explain many features of our mental lives. Churchland points to the following features that folk psychology fails to explain:

We do not know what sleep is for, or why we have to have it, despite spending a full third of our lives in that condition. (The answer, “For rest,” is mistaken. Even if people are allowed to rest continuously, their need for sleep is undiminished. Apparently, sleep serves some deeper functions, but we do not yet know what they are.) We do not understand how learning transforms each of us from a gaping infant to a cunning adult, or how differences in intelligence are grounded. We have not the slightest idea how memory works, or how we engage to retrieve relevant bits of information instantly from the awesome mass we have stored. We do not know what mental illness is, nor how to cure it.

Reason 2: Throughout history, human beings have been trying to explain the world around them. In doing so they come up with unsophisticated theories, folk theories, about how things work. There have been folk theories about the heavens, about life, about the elements, about society, and so on. Most of these early theories have turned out to be false and have been displaced by more sophisticated theories. So it’s likely that folk psychology is just as bad as all these other folk theories. The reason it has survived as long as it has is because its subject matter – human behavior – is much more complex. We are just beginning to understand how the brain works, so we shouldn’t be surprised that it will take a while before folk psychology will be displaced by neuroscience.