state an intentional object. Going through Mindy’s other mental states, it’s not too hard to pick out their intentional objects. Her achy feeling is about her muscles, her excitement is about her prospective goal, her desire is about scoring and her belief and memory are about the goalkeeper. In contrast, Mindy’s non-mental states don’t seem to be about anything. Mindy’s height and muscle fatigue aren’t about anything – they just exist without pointing beyond themselves.
An interesting feature of intentionality is that something can have an intentional object even when that object does not exist. A desire to find the Holy Grail is about the Holy Grail, even if no such object exists. A perceptual experience of a floating dagger is about a dagger, even though no such dagger is present. A belief in fairies is about fairies, even though there are no such creatures. We can make sense of this distinctive feature of intentionality by making an analogy with paintings. Some paintings are paintings of real things. Holbein’s portrait of Henry VIII, for example, is of a real flesh-and-blood person. Other paintings are not of real things. Burne-Jones’s painting The Beguiling of Merlin is a painting of Merlin, even though no such magician exists. So the fact that a painting is about something does not entail that thing exists. Similarly, a mental state being about something does not entail that thing is real. Mental states and paintings both point beyond themselves to something else, and they can do so regardless of whether there’s anything real they are pointing to (this feature of intentionality is a philosophical rabbit hole down which we won’t be going, but some readings that do venture down the hole can be found at the end of the chapter).
So far we’ve seen that at least some mental states have the property of intentionality and some non-mental states lack intentionality. But for intentionality to be the mark of the mental, something much stronger is needed: it must be the case that all and only mental phenomena have intentionality. The thesis that intentionality is necessary and sufficient for mentality was named Brentano’s thesis after Franz Brentano (1838–1917). Although this idea has a long history running back at least to Aristotle, Brentano made a particularly influential case for it. One motivation for Brentano’s thesis is the thought that to have a mind is to have a perspective on the world – a point of view. Mindy has one perspective on the world, the goalkeeper has a different perspective, and the referee another. The mindless football, on the other hand, has no perspective at all. Nor do the goalposts or the referee’s whistle. Having a perspective means having a perspective on or about something. So perspectives come hand-in-hand with intentionality. Mindy’s perspective on the world is made up of all her intentional states: her beliefs about things in the world, her perceptions of them, her feelings about them, and so on. The goalkeeper’s perspective is made up of a completely different set of mental states: different beliefs, perceptions, feelings and so on. What makes those states mental states is that they are constituents of a perspective, and what makes them constituents of a perspective is their intentionality. Mindy’s non-intentional states cannot be constituents of her perspective on the world, and this is what makes them non-mental. If you buy into this equation of minds with perspectives, you’re a long way towards agreeing with Brentano’s thesis.
To properly evaluate Brentano’s thesis we need to consider whether it is vulnerable to counter-examples. Can we undermine Brentano’s thesis with a non-mental case of intentionality? Well, we’ve seen already that paintings can have intentionality, like a portrait being of Henry VIII. Similarly, the map in my drawer is about Cambridge, the book on my desk is about philosophy and the reading on my thermostat is about the temperature. All of these things have intentional objects, yet none of them plausibly have mental states. Advocates of Brentano’s thesis deal with such cases by arguing that these things only have intentionality because we give it to them. The painting is a painting of Henry VIII (rather than of his brother or of a fictional king) because that’s who Holbein meant it to be of. The map is of Cambridge because the map-makers designed it to be. And the reading on the thermostat is about the temperature because that is the function it was given. A bunch of stuff happening in a box on the wall is meaningless without the wider context of people who design and use thermostats. On this view, one of the things that beings with real intentionality can do is imbue non-mental things with this kind of derivative intentionality. But non-derivative intentionality remains an exclusively mental property.
Can we undermine Brentano’s thesis with a mental state that is non-intentional? It’s unlikely that perception will provide such a counter-example. We normally describe our perceptual states in terms of what they’re about – a perception of a cat, or of a cup or of a cake. In fact, it is hard to see how something could be a perception without being a perception of something. It’s also unlikely that propositional attitudes will provide a counter-example. A propositional attitude is about whatever figures in the proposition. It also looks like intentions are inevitably intentional (though not because of the superficial similarity of the terms). Intentions are directed at whatever they are intentions to do. Pains might cause more trouble. One might argue that pains aren’t really about anything – they just are. Emotions can also cause difficulties. Although emotions like Mindy’s elation have a clear intentional object, other emotions seem to be undirected. Your mood might be cheerful, or grumpy, or melancholy, yet none of these emotions need to be about anything in particular. Maybe we can say that these emotions are about the world in general but there would have to be good arguments for understanding them that way.
The claim that intentionality is the mark of the mental certainly deserves to be taken seriously. But even if we stop short of advocating Brentano’s thesis, the foregoing provides us with something useful. First, it gives us some idea of how to draw the line between the mental and the non-mental, and thus of how to delineate the subject matter of philosophy of mind. Second, it gives us the valuable concept of intentionality to put in our conceptual toolkit. My initial sketch of what was going on in Mindy’s mind was a sketch of her perspective – her take on the world – with different mental states contributing to that perspective in their own distinctive ways. Understanding the mind will at least partly be a matter of understanding someone’s perspective, and we can apply that insight as we begin to explore the big questions that define the philosophy of mind.
1.4 The Three Big Questions
The mind invites a huge range of philosophical questions. Some of these we’ve come across in the last two sections – questions about the nature of perception, emotion, pain and so on, questions about the mark of the mental, perspectives and intentionality. And there are countless other questions that we won’t even touch upon. My focus in this book will be on the Three Big Questions:
1 The Mind and Matter Question: What is the relationship between mind and matter?
2 The Knowledge Question: How do we acquire knowledge of our own minds and the minds of others?
3 The Distribution Question: Which things have minds and what kind of mind do they have?
So what marks these out as the questions most deserving of our attention? Over the rest of this section, we’ll see that how we answer has important ramifications for how we answer the smaller questions. It’s hard to give an account of the nature of pain, for example, without taking a stance on the relationship between mind and matter. And over the rest of this book we’ll see that the most important theories in philosophy of mind are defined by how they answer the Big Questions. In fact, the whole history of philosophy of mind can helpfully be framed as the history of thought on these questions. With that in mind, let’s consider each question in turn.
1.4.1 The Mind and Matter Question
The Mind and Matter Question invites us to make sense of how the mind fits into the material world. The material world is the world of matter – of physical objects distributed in space and time and governed by the laws
