different things are made out of the same kind of stuff, namely matter. If you want to know about matter, ask a physicist. They’ll tell you that there’s a small set of fundamental particle types – things like quarks and leptons – that make up the entire universe. And the behaviour of those particles is governed by a small set of physical laws. Think of it like a giant Lego set: from a few types of brick and some basic rules governing how they fit together, a near-infinite variety of things can be made. To be a material object is to be either one of the basic physical building blocks of the material world, or to be something made out of those basic physical building blocks. So our question is whether the mind is constituted by physical building blocks or whether it introduces a whole new immaterial constituent to reality.
Materialists (aka physicalists) claim that there are no immaterial entities: that everything in the universe is constituted by the great material Lego set. Minds are no exception to this. Mindy’s mind is constituted by a material object – presumably her brain. The challenge for the materialist is to make sense of how this could be so. How can Mindy’s beliefs be a state of Mindy’s brain? How can her decisions be a neural process? How can her perceptions be a sparking of neurons? Dualists adopt the anti-materialist view that the world includes at least some immaterial entities, namely minds. Distinct from Mindy’s physical body is a non-physical mind – something that cannot be constituted by the physical building blocks described by physics. The challenge for the dualist is to make sense of where immaterial minds come from and how they’re connected to the brain.
A key battleground for materialists and dualists is causation. Mindy’s visual experience is caused by physical events such as light hitting her retina in a particular way. And Mindy’s intention to kick the ball causes the physical event of her kicking it. How can we make sense of these causal interactions? For materialists, these interactions take place within the material world. The story of Mindy’s penalty kick is a completely physical story, and the challenge for materialists is to make sense of how Mindy’s mental states fit within that story. For dualists, these interactions take place between physical and non-physical things. The story of Mindy’s penalty kick involves both events in the material world and events in Mindy’s immaterial mind, and the challenge for dualists is to make sense of how these two kinds of event hook up. The challenges here run deep, and both sides must confront the possibility that the apparent interactions between mind and body are not as they seem. Perhaps Mindy’s perceptual experiences aren’t really caused by her environment and perhaps her intentions aren’t really the cause of her actions. This is a threat we’ll be coming back to throughout the book.
How we answer the Mind and Matter Question can have huge implications for how we see ourselves and how we live our lives. Do we have a special place in nature, standing apart from the world of material entities, or is the mind smoothly continuous with the rest of the material world? Do we come into existence when our brain comes into existence or might our minds predate our bodies? Do we die when our body dies or could the mind survive our bodily death? Are we really responsible for our actions or is our behaviour outside our control? Each of these urgent questions comes back to the core question of how mind and matter are related.
1.4.2 The Knowledge Question
Metaphysics asks about the nature of reality and the Mind and Matter Question is a central question in the metaphysics of mind. The Knowledge Question, by contrast, is an epistemological question about our knowledge of mental states: how do I know what’s going on in my own mind or in the minds of others? The first thing to notice is that the way you know about your own mind is quite different to the way you know about other minds. You can only know about Mindy’s muscle pain from its outward signs – things like her facial expression or her verbal reports – but she knows about her muscle pain from the inside. There’s thus an epistemic asymmetry between knowledge of one’s own mind and knowledge of other minds.
It’s tempting to say that we know our own minds via a kind of inner sense. Just as Mindy knows what’s going on around her through perception, she knows what’s going on in her own mind through introspection. But what is this introspection and how does it work? We can also ask about how secure our self-knowledge is. Can you think you are in a mental state but be wrong? Perhaps Mindy can misidentify her nervousness as excitement, but it’s harder to make sense of her being wrong that she’s in pain. Can you be in a mental state without knowing that you are? We can make sense of Mindy having memories she doesn’t know about, but it’s harder to make sense of her failing to know that she’s in pain.
What about our knowledge of other minds? Our knowledge of other minds seems less secure. Mindy knows her own intentions quite clearly but has a much harder time working out which way the goalkeeper intends to dive. Does she learn about the goalkeeper’s mind by perceiving her behaviour, by imagining her point of view, or by some combination of the two? If the goalkeeper acts like she wants to win the game, how does Mindy know she’s not just pretending to have this desire? If the goalkeeper reports liking the smell of old socks, how does Mindy know that socks smell the same way to the goalkeeper as they do to her? Can we ever really know what’s going on in the goalkeeper’s mind or are we effectively just guessing? Could brain scans and advanced psychological investigation give us more direct access to the goalkeeper’s mind, or are her mental states always hidden from us? How confident can we be that the goalkeeper even has a mind?
These epistemological questions are bound up with the metaphysical questions discussed earlier. If the mind is a material thing, then we need an account of how we know about our brain states and the brain states of others. If, on the other hand, the mind is immaterial, we need an account of how we can gain knowledge of these special non-physical states. These epistemological questions also have deep practical and ethical implications. When is it wrong to doubt someone’s report of what’s going on in their mind? Is it ever right to think that you know what someone wants better than they do? Can a juror ever really know that the accused intended to kill? Can a probation officer ever really know that a murderer doesn’t desire to kill again? Our answers to these more concrete epistemological questions will be shaped by our answer to the Knowledge Question.
1.4.3 The Distribution Question
There are lots of things in the world, but which of them have minds? If you’re watching the football game, you’ll be pretty sure about the distribution of minds. You’ll be confident that Mindy, the goalkeeper and the referee each has a mind. You’ll also be confident that the ball, the goalposts and the referee’s whistle don’t have minds. But is this confidence well founded? And in many circumstances we’re not so confident about the distribution of minds. Does a newborn baby have a mind? What about a foetus, or a zygote? Does your pet cat have a mind? What about a bat, a bee or an octopus? Should we attribute minds to trees, to plants or to viruses? Could there ever be an AI with its own mind? What about the internet, a smartphone or a self-driving car? Might it be that everything has a certain level of mindedness and that mentality pervades the universe? Or might it be that nothing does and that the whole idea of minds is a myth?
Once we’ve decided which things have minds, there remains the further question of what kind of mind they have. If a foetus has a mind, is it a conscious mind or a mind populated only by unconscious mental states? If an octopus has a mind, is it a rational mind like ours or a bundle of instinctive mental processes? If a self-driving car has a mind, is it an emotional mind with feelings of love and hate or is it emotionally inert? Besides asking these general questions about the distribution of consciousness, rationality and emotion, we can ask some more specific questions about the distribution of specific mental state types. For instance, which of these beings can feel pain and which cannot?
The Distribution Question has an epistemological aspect. How do we know whether something has a mind or what kind of mind it has? What criteria should we be applying and how confidently can we apply them? It also
