Читать книгу What is Philosophy of Mind? - Tom McClelland - Страница 8

Since we’re going to be asking philosophical questions about the mind, it will help to have a clearer idea of our subject matter. The mind is, after all, a highly complex and multifaceted thing. To know your way around the mind, you need to have a grip on the full range of mental phenomena that make up our mental lives. Let’s start by examining the different mental states that someone has at a specific time.

Our subject – let’s call her Mindy – is the striker for her university football team (by which I mean ‘soccer’ team). It’s the cup final and, in the last minutes of the game, her team has been awarded a penalty kick. If she scores the penalty, her team will surely win. As she strides up to the penalty spot, what’s going through Mindy’s mind? She can hear the crowd cheering, taste the sweat dripping into her mouth, and smell the cut grass. She can feel the mud on her knees and the pain in her muscles. She sees a whole visual scene before her: the ball on the penalty spot, the goalkeeper in the goal, the crowd watching behind. She feels a buzz of excitement mixed with a pang of dread. She thinks about where to aim her shot. She wants to score and believes that the best way to do this is to go the opposite way to the goalkeeper. She remembers that the last time the goalkeeper faced a penalty she dived to the right of the goal and Mindy infers that she’ll dive the same way today. She decides to aim for the left and imagines kicking the ball hard into the bottom left corner. She runs up to the ball, kicks it and scores. She feels a huge rush of elation and runs to her teammates to celebrate.

In those few moments, Mindy has experienced a whole variety of mental phenomena. Let’s start with what Mindy perceives. We perceive things through our senses – a set of systems that register information about our environment through our sense organs. Mindy hears the crowd, smells the grass, tastes the sweat, feels the mud and sees the scene before her. This covers the five main senses: hearing, smell, taste, touch and sight. Mindy will also have perceptual states generated by two other sensory systems: the vestibular system, which is responsible for our sense of balance, and the proprioceptive system, which is responsible for our sense of where our body is positioned. Another thing Mindy experiences is the pain in her muscles. This might be classified as a bodily sensation, like the feeling of mud on her knees. Alternatively, it might be classified as a kind of ‘hedonic feeling’. On this view, feelings like pain or pleasure tell us how good or bad something is rather than conveying sensory information.

Now let’s consider Mindy’s emotions. She experiences excitement, dread and – once she’s scored the goal – elation. Each emotion has several different aspects. Mindy’s feeling of elation, for example, has a physiological component: her heart rate and blood pressure go up. The emotion also constitutes a kind of evaluation of the situation Mindy is in: it presents the goal to Mindy as being a good thing in some way. The emotion manifests itself in Mindy’s behaviour: she sprints to celebrate with her teammates. It also manifests itself in her expressions: her eyebrows raise, her mouth opens, her arms go up in the air. It’s a matter of some debate where to locate the emotion itself in all this. Perhaps elation is something that causes these things to happen, or perhaps being elated is just an amalgam of all these things. It’s also hard to pin down what the experience of an emotion contains: is the feeling of elation just the feeling of your heart rate increasing, your facial expression lifting and so on, or is there also some distinctive feeling of elation separate from these peripheral things?

Next up are Mindy’s thoughts. Thoughts come in various forms, many of which Mindy exemplifies. Her thoughts include: a desire to score; a belief that scoring is best achieved by going the opposite way to the goalkeeper; a memory that the goalkeeper went right in the past; another belief that the goalkeeper will go right again; an intention to kick the ball to the left; and an imaginative experience of scoring the goal. The first thing to notice about these different thoughts is how they fit together. Her intention is justified by a rational process involving her beliefs, her desires and her memories. Reasoning is not a specific mental state but rather a mental process that unfolds over time and that encompasses all sorts of different mental states. How Mindy reasons about her situation plays a big role in determining what she thinks. This is quite different to perception – when Mindy looks at the goal she sees the goalkeeper, and no amount of reasoning can stop her from seeing the goalkeeper. It’s also quite different to emotion – when Mindy feels an emotion, she can’t easily reason herself into having a different emotion. We should stop short of claiming that perception and emotion are completely unresponsive to reasoning. Sometimes the way we perceive or feel about a situation is influenced by our rational thoughts. Nevertheless, there is a clear sense in which perceiving and feeling are outside our direct rational control in a way that thinking is not.

Another thing to notice about Mindy’s thoughts is that they each share a common structure. Bertrand Russell (1872–1970) introduced the term propositional attitude to describe the different mental attitudes that we can take towards a given content. In the sentence ‘Mindy believes that the goalkeeper will go left’, the propositional attitude is belief and the proposition is that the goalkeeper will go left. Propositions are typically designated using a ‘that’ clause, and a propositional attitude is typically specified by whatever verb precedes the word ‘that’. Propositions are things that can be true or false. The proposition that the goalkeeper will go left, for instance, is true if the goalkeeper in fact goes left and false if not.

Notice that Mindy can adopt different attitudes towards the same proposition: she can hope the goalkeeper will go left, desire that the goalkeeper will go left, imagine that the goalkeeper will go left and so on. And she can also adopt the same attitude towards different propositions: she can believe that it’s the cup final, believe that she’s about to score, believe that tonight will be a riotous party and so on. All these different thoughts have the same structure: they are constituted by a propositional content and a mental attitude towards that content. This list makes the structure more explicit by italicizing the propositional attitude and underlining the proposition:

Mindy desires that she will score the penalty

Mindy imagines that she will score the penalty

Mindy remembers that the goalkeeper went left in the past

Mindy intends that she will kick the ball to the left-hand

side of the goal

Mindy believes that the goalkeeper will go left

Mindy believes that scoring is best achieved by going the

opposite way to the goalkeeper

Notice that the first two thoughts are constituted by Mindy having different propositional attitudes to the same proposition, and that the last two thoughts are constituted by Mindy having the same propositional attitude to different propositions. The concept of propositional attitudes offers a useful way of capturing how different thoughts resemble and differ from one another.

One complication here is that some of these thoughts involve more than just adopting a particular propositional attitude. For instance, when Mindy remembers that the goalkeeper went left in the past, she might have a vague mental image of their last dive. Similarly, when Mindy imagines scoring, she might have a vague mental image of the ball hitting the back of the net. Here it seems that Mindy’s thoughts have a kind of perceptionlike component that would need to be included in a complete account of thought.

The final group of mental states we will consider are volitions. We have seen lots of different mental states leading up to Mindy stepping forward and kicking the ball, but none of these mental states are enough to make Mindy actually do anything. Even once she’s reasoned through what to do, even once she’s formed an intention to go for the bottom-left corner, a volition is needed to put her body into motion. This volition might be described as an act of will. Volitions are the things that turn thought into action – they are the mental states that make things happen. Some hold that this concept of volitions overcomplicates matters. They argue that intentions can cause actions and that there’s no need for a third kind of mental state mediating between the two. For our purposes, we can remain neutral on whether we really have volitions.

The states we’ve considered have all been conscious mental states – states of which Mindy is aware. But there are good reasons for thinking that our conscious mental life is just the tip of the iceberg, and that below the surface there are countless unconscious mental states. Some unconscious mental states can easily be brought into consciousness. You have the unconscious belief that Paris is the capital of France, but now that I’ve raised the topic of France’s capital, that belief will have become conscious. Other unconscious mental states are much harder to retrieve. You might have an unconscious desire to murder your neighbour that only becomes conscious after months of psychotherapy. There might even be mental states that can never enter our consciousness. Your visual experience is the product of many stages of sensory processing and what goes on in the early stages of this process could well be inaccessible to us.

Many of the mental states we’ve considered come in conscious and unconscious varieties. The propositional attitudes offer some clear cases. Although Mindy is conscious of some of her beliefs, countless others of her beliefs are unconscious. She has beliefs about the history of the World Cup, beliefs about what’s on her bookshelf at home, beliefs about the capitals of European countries, and so on. The same goes for desires. Mindy has a desire to get new football boots, a desire to learn to juggle and a desire to go travelling, but none of these desires are conscious while she’s taking the penalty kick. Memories are another good case. Mindy has memories of her childhood, memories of last week’s training session and memories of this morning’s breakfast, but these memories are all unconscious. What about imagination? Can Mindy unconsciously imagine that she’s going to be made captain? The answer’s not so clear, but it’s at least a live possibility that there are such unconscious imaginings.

Moving on to perception, psychological research has revealed that some perceptual states occur unconsciously. In subliminal perception, your mind registers a stimulus without you being aware of it. Let’s say that the big screen at the football ground quickly flashes an advert for Jaffa Cakes. Mindy could perceive this advert, without even consciously experiencing it. Later on, she might even find herself with an inexplicable craving for Jaffa Cakes! The sensation of pain is an interesting case. It’s tempting to say that you can’t be in pain without that pain being conscious. But what if Mindy were to say, ‘I didn’t notice the pain in my ankle’? Should we conclude that Mindy had an unconscious pain or that the pain only started when Mindy started to have a conscious experience of pain? To answer this, we’d need to refine our understanding of what it is to be in pain and, indeed, our understanding of what it is for a mental state to be conscious.

Can you have emotions you aren’t conscious of? We can imagine Mindy saying, ‘It was only after the final whistle that I realized how nervous I’d been’. Perhaps this describes an unconscious emotion of nervousness. If you’re angry at someone all day, must you be conscious of your anger all day or can your anger sometimes be bubbling away unconsciously? The answer will again depend on how we understand the nature of emotions and the nature of consciousness, but it’s certainly an open possibility that our unconscious mind is populated by emotions.

What about volitions? On the one hand, you could argue that volitions have to be conscious. It’s not clear how something could be an act of will if it’s unconscious. On the other hand, there are lots of actions we perform without any conscious volition. When absentmindedly driving a familiar road, for example, perhaps each change of gear is the result of an unconscious volition. Again, it’s an open question.