The Difficulty of Philosophy of Mind
A summary of views concerning the mental: it's not just one hard problem
Let’s start at the pre-philosophical level. It seems obvious that the mental and physical realms exist and interact. These are common sense practical positions one adopts — perhaps in childhood — before engaging in mature philosophizing. Problems arise in such engagement.
What is the explanation for these realms and their interaction?
Regarding the nature of the human person, one might be a substance dualist: there are mental substances and physical substances; the human comprises both. So far so good. But how can two radically different realms interact? One might be a monist instead: the human person is wholly physical (i.e., physicalism); or perhaps the human person is wholly mental.
I want to focus on a separate issue: consciousness and its properties. Here, we can use a similar division. One can be a dualist and claim that consciousness involves both physical properties and non-physical mental properties. One can be a monist and hold, say, that consciousness is totally physical. Regarding dualism, we can again raise the question of interaction. I can mentally direct my physical hand to handle a cup of coffee; the physical coffee brings about changes in my mental states if I drink it. How does that work?
Monism comes in various types. Consider physicalism and idealism. The physicalist/materialist claims that only the physical/material realm exists. All is physical. This position affords an explanation for how physical and mental things interact: both are material in nature and they play ball on the same field. Yet mental phenomena seem plainly non-physical. It looks like a category mistake to say that the what-it-is-like experience of smelling cinnamon or feeling lower back pain falls wholly into the physical category. It seems clear that phenomenal consciousness isn’t physical. So how can everything be physical?* Moreover, at least some mental states have intentionality. They are about something. But no physical state has intentionality. Physical states aren’t about anything. Hence, some mental states are not physical. If this reasoning holds, then not everything is physical.
The idealist claims that only the mental exists. All is mental. Again, this position explains how things interact. And again, problems arise. Some things seem physical. How so, if all is mental? Further, as Moore argued in The Refutation of Idealism, there is a distinction between the act of consciousness and its object. It appears that idealism is not the best account for this distinction.
Back to dualism. There isn’t a definitive answer to how the mental and physical realms interact if dualism is true. The dualist can bite the bullet and say “Look, I understand that objection. I don’t know how the mental and physical interact. Yet we shouldn’t assume that if we don’t know how one thing causes another, it follows that there is no reason to believe that the two things interact. In any case, I think dualism is the best option. I hope an explanation for interaction comes soon. For now, I take a mysterian position on the interaction question.”
Similarly, there isn’t a conclusive argument for how physicalism explains consciousness — especially qualia. The physicalist can also turn to bullet-biting. “Well, I’m committed to the worldview of naturalism. For me, physicalism must be true. But every view has its problems. I have no idea how consciousness is physical. I have faith that, one day, we’ll discover the explanation. For now, I take a mysterian position.”
What about the idealist? What’s the idealist’s account for the obviousness of the material?
Well, says the idealist, if you think about the problem, our experiences of the (supposed) physical realm involve sensations of various kinds: seeing the sense-data of the tree in the yard (or do we see the tree itself?); hearing the crashing of the ocean waves; touching the cold powdery snow; smelling the espresso coffee; tasting the ripe lemon. These sensations are mental states. There is no way to get outside them to experience the (supposedly) material world. Russell aptly described the problem in Chapter 1 of The Problems of Philosophy:
“To make our difficulties plain, let us concentrate attention on the table. To the eye it is oblong, brown and shiny, to the touch it is smooth and cool and hard; when I tap it, it gives out a wooden sound. Anyone else who sees and feels and hears the table will agree with this description, so that it might seem as if no difficulty would arise; but as soon as we try to be more precise our troubles begin… Thus it becomes evident that the real table, if there is one, is not the same as what we immediately experience by sight or touch or hearing. The real table, if there is one, is not immediately known to us at all, but must be an inference from what is immediately known. Hence, two very difficult questions at once arise; namely, (1) Is there a real table at all? (2) If so, what sort of object can it be?
“It will help us in considering these questions to have a few simple terms of which the meaning is definite and clear. Let us give the name of 'sense-data' to the things that are immediately known in sensation: such things as colours, sounds, smells, hardnesses, roughnesses, and so on. We shall give the name 'sensation' to the experience of being immediately aware of these things. Thus, whenever we see a colour, we have a sensation of the colour, but the colour itself is a sense-datum, not a sensation. The colour is that of which we are immediately aware, and the awareness itself is the sensation. It is plain that if we are to know anything about the table, it must be by means of the sense-data—brown colour, oblong shape, smoothness, etc.—which we associate with the table; but, for the reasons which have been given, we cannot say that the table is the sense-data, or even that the sense-data are directly properties of the table. Thus a problem arises as to the relation of the sense-data to the real table, supposing there is such a thing.
The real table, if it exists, we will call a 'physical object'. Thus we have to consider the relation of sense-data to physical objects. The collection of all physical objects is called 'matter'. Thus our two questions may be re-stated as follows: (1) Is there any such thing as matter? (2) If so, what is its nature?”
Now, why posit a material world at all? Why not stick to the deliverances of experience? These deliverances suggest that all is mental, or at least that all we can know is the mental.
One concern about idealism is that it is a step or two away from solipsism, and solipsism seems very hard to accept. Another problem is Moore’s argument (noted above). At this point, the idealist might join the bullet-biting match: “Yes, idealism is problematic. But so are the other options. I believe that, in the end, idealism will win the day. For now, I punt to mystery.”
Is there another option? Well, one might claim that there is another version of monism. On this view, there is only one kind of thing. This thing is neither mental nor physical, yet its existence explains mental and physical phenomena. What is this thing? Nobody knows. It’s a mystery.
What about functionalism? Functionalism is an attempt to avoid the problem of explaining what substances exist and how they might account for mental and physical phenomena. The functionalist need not take a position on the monism vs. dualism debate. Instead, functionalists focus on what minds do, i.e., mental functions.
The mousetrap is a common example of the functionalist strategy. To understand what a mousetrap is, one need not explain the substance(s) used to create it. Rather, a mousetrap is whatever accomplishes the task of trapping mice (e.g., a device with wood and springs; a box with poison; a cat). There are various ways to make such a device; any way counts as long as it works. Pragmatism rules here. Similarly, the functionalist argues, we don’t need to discover the substance(s) responsible for consciousness. Any substance will do as long as it performs the relevant functions. What makes a mental state a mental state is a matter of what it does, not what it is or the substance which grounds it. Regarding the mind, anything counts as mental as long as it does the job, just as anything counts as a mousetrap so long as it catches mice.** Results matter, not questions about matter.
Does functionalism face problems? Yes, and they are serious ones. First, Searle’s Chinese Room argument is an effective objection to input-output functionalism. The Chinese Room has relevant inputs and outputs. But the room doesn’t understand Chinese, nor is it aware of anything — at least not in the qualitative or phenomenal sense, though one might argue that the room ‘understands’ in a merely functional sense. Moreover, there is nothing that it is like to be a room. Rooms are not conscious in the phenomenal sense. The same points hold for computers and mere collections of neurons and brain material. There is nothing it is like to be a computer. There is nothing it is like to be a brain or a neuronal firing.*** Can functionalism address these problems adequately? So far, there are no dispositive answers. Functionalists have their mysteries too.
Back to Russell:
“Such questions are bewildering, and it is difficult to know that even the strangest hypotheses may not be true. Thus our familiar table, which has roused but the slightest thoughts in us hitherto, has become a problem full of surprising possibilities. The one thing we know about it is that it is not what it seems. Beyond this modest result, so far, we have the most complete liberty of conjecture. Leibniz tells us it is a community of souls: Berkeley tells us it is an idea in the mind of God; sober science, scarcely less wonderful, tells us it is a vast collection of electric charges in violent motion.
Among these surprising possibilities, doubt suggests that perhaps there is no table at all.”
Russell’s reference to doubt is intriguing. Consider an epistemological point: perhaps a non-global skepticism is true; we lack knowledge in these areas. Maybe we can’t obtain such knowledge but must settle for some version of (nondogmatic) reasonable belief. There are many competitors in the competition for reasonable belief. We don’t know which competitor (if any) is victorious. We can’t shake loose from mystery. The good news: we retain wonder, the beginning of philosophy and a sign that one is a philosopher — or so says Socrates. (Theaetetus 155d)
* There are two options for the physicalist: reductive materialism and eliminative materialism. The former is hard to defend in the face of strong objections; the latter seems too far-fetched.
** You might see how this view is useful in defending the claim that computers, robots, AI systems, etc. are conscious. Such things might function as if they were conscious, and to function as if conscious is to be conscious. The as if and the is come together.
*** This is sometimes called the problem of absent qualia.