Posts on the Philosophy of Mind

Regular readers will know that I recently completed a series of posts on the philosophy of mind. All were based on material found in William Jaworski's book Philosophy of Mind: a Comprehensive Introduction. The following is a list of all these posts.


1. Philosophy of Mind: Mapping the Theoretical Space

2. Substance Dualism (Part One): The Basic Argument

3. Substance Dualism (Part Two): Criticisms of the Basic Argument

4. Substance Dualism (Part Three): The Problem of Other Minds

5. Substance Dualism (Part Four): The Problem of Interaction

6. Substance Dualism (Part Five): Explanatory Impotence

7. Mind-Body Physicalism (Part One): Argument from Past Explanatory Success

8. Mind-Body Physicalism (Part Two): Hempel's Dilemma

9. Mind-Body Physicalism (Part Three): The Knowledge Argument

10. Mind-Body Physicalism (Part Four): Absent and Inverted Qualia

Mind-Body Physicalism (Part Four): Absent and Inverted Qualia

(Part One, Part Two, Part Three)

Right now I am looking at my laptop. To me it appears to be grey and black. Or at least, “grey” and “black” are the names I’ve come to associate with the colour experiences that I have when I look at it. Convention being what it is, you would probably associate the same names with your colour experiences of my laptop, but would our colour experiences really be the same? How do I know that your “black”-experience is not similar to my “green”-experiences?

These questions point us toward the problem of absent or inverted qualia. This problem forms the basis of an objection to mind-body physicalism that will be front and centre in today’s post. The post is part of a series on mind-body physicalism. And the series follows the material in William Jaworski’s Philosophy of Mind: a Comprehensive Introduction .


1. The Argument from Absent or Inverted Qualia
In the previous post, we discussed Frank Jackson’s famous knowledge argument against physicalism. This argument appealed to the private facts of experience (qualia), and their apparent separation from the subject matter of the physical sciences, in an effort to undermine physicalism. The argument from absent or inverted qualia does something similar. The argument itself looks like this:

• (1) If absent or inverted qualia are possible, then physicalism is false.

• (2) Absent or inverted qualia are possible.

• (3) Therefore, physicalism is false.

On the face of it, this is very simple stuff. But, of course, the devil is in the detail. We need to know exactly what absent or inverted qualia are and why they imply that physicalism is false; and we also need to know why absent or inverted qualia are possible. Let’s look at each of these issues in turn.

Inverted qualia are easily explained since they were alluded to in the intro. Qualia can be said to be inverted if different people have different qualitative experiences associated with the sensation of the same objects or states of affairs. As in your “black”-experience is equivalent to my “green”-experience. Absent qualia are slightly different. They can be explained by reference to the (infamous) philosophical concept of zombies. These are beings who are externally identical to us - i.e. they walk the same walk, and talk the same talk - but who completely lack the qualitative experiences we associate with activities such as walking and talking (note: there’s nothing special about these activities; I chose them for illustrative purposes only).

Why would either of these phenomena pose of problem for physicalism? Well, if physicalism is true, then qualia would have to be either (i) physical states of some sort or (ii) non-existent. Since we all appear (from our own perspective) to be having qualitative experiences, (ii) would seem like a non-starter. So qualia must be physical states. But if they are physical states, then their presence should be determinable by identifying physical states such as patterns of brain activation. This is where absent or inverted qualia become important. If such things are possible, then the same physical states can either (a) be associated with different qualitative experiences or (b) be associated with no qualitative experiences at all. But this can’t be right if qualia are identical to physical states. So the possibility of inverted or absent qualia would indeed imply the falsity of physicalism. Let’s phrase this in the form of an argument:

• (4) If physicalism is true, then qualitative states (qualia) must identical to specific physical states.

• (5) If absent or inverted qualia are possible, then the same physical state can be associated with completely different qualitative states.

• (3) Therefore, if absent or inverted qualia are possible, physicalism is false.

Finally, let’s move on to consider why absent or inverted qualia are possible. Again, if you’ve been following this series closely, it should come as no surprise to learn that a conceivability-possibility principle is doing all the work here. Proponents of the argument will say that since zombies and inverted qualia are conceivable (you just conceived of them as you were reading this, right?), they are also metaphysically possible. Hence, premise (2) of the argument is justified.


2. Responding to the Argument
In Chapter 4, Jaworski doesn’t go into the various responses to this argument in any great depth. This is mainly because he addresses them elsewhere in the book. His discussion of this argument is among the first stops on a very long trek through all the different physicalist theories. Still, a few words can be said about possible responses.

First, the argument relies on the dubious conceivability-possibility principle. We discussed the problems with this when looking at substance dualism. I advise the interested reader to read back over that discussion. In any event, even if the principle is sound, it is open to the physicalist to object to the true conceivability of absent or inverted qualia. They could say that the relevantly similar physical states must, necessarily, be associated with the same qualitative states. In doing so, they can challenge the proponent of the argument to come up with a clear and distinct conception of both phenomena.

Second, physicalists can reject the reality of qualia. As counterintuitive as it seems, several have taken this route. Daniel Dennett is probably the most well-known exponent of this view, but Wittgenstein’s private language argument has similar implications. Jaworski discusses both in chapter 8. To make this series somewhat self-contained, I’ll present Dennett’s argument now (I won’t evaluate it though).

Qualia are typically defined as properties that are (a) intrinsic/non-relational and (b) directly knowable. They are non-relational in that they do not play a part in the kinds of causal relations analysed by physicalists; and they are directly knowable in the sense that they are known non-inferentially from the first-person perspective. Dennett denies that qualia can be both of these things at the same time. His argument starts by assuming that proponents of qualia think that qualia play some role in our behaviour and then deduces from this the fact that qualia cannot exist. It looks like this:

• (6) Exponents of qualia must claim either (i) that qualia influence behaviour in conjunction with our beliefs, desires and other propositional attitudes; or (ii) that qualia influence behaviour independently of propositional attitudes.

• (7) If qualia affect behaviour independently of our propositional attitudes, then qualia cannot be non-relational.

• (8) If qualia affect our behaviour in conjunction with our propositional attitudes, then qualia cannot be directly knowable.

• (9) Therefore, qualia cannot be both non-relational and only directly knowable.

Premise (6) might seem a little odd, but it makes sense. Speech acts such as verbal reports are a kind of behaviour. So if speech acts like “I see a blue ball” or “I see a red ball” are linked with qualitative experiences — as proponents of qualia would have us believe — then those experiences must exert some influence on our behaviour.

Premise (7) is supported by the idea that if qualia directly influence behaviour, then they must do so by playing a direct causal role in behaviour, i.e. < Red quale → “I see red” >. So they would have to be defined in relational, as opposed to non-relational terms.

Premise (8) is a little trickier. The idea is that if qualia only influence behaviour when they are conjoined to other beliefs and desires, then one cannot know one’s qualia without knowing those other beliefs and desires. In other words, qualia can only be known when the surrounding circumstances are known. Dennett supports this idea with a few thought experiments. Here’s one:

• (10) Mad Scientist : A mad scientist has manipulated your brain while you were asleep. When you wake up, you declare that your sensory experiences are qualitatively different from the way they were before. But how can you know this? It could be that the mad scientist succeeded in altering your qualitative experiences, or it could be that he altered your memories. Either is possible if it is “qualia + beliefs” that influence behaviour. One can only tell the difference by knowing something about one’s memories and/or the brain states manipulated by the mad scientist.

This probably seems a little strange. It does to me, at any rate. But Dennett argue that denying the existence of qualia need not be as counterintuitive as it first appears. He reckons that a third-person conception of mental phenomena can accommodate most of the facts cited in support of qualia. He does so partly on the grounds that many phenomena that are thought to be non-relational turn out, on closer inspection, to be relational.

Like I said, I won’t evaluate this here but one obvious objection should be noted. The first premise of Dennett’s argument (premise 6 above) assumes that qualia influence behaviour. There is at least one school of thought — epiphenomenalism — that would deny this.

Okay, well that’s it for this series. As I said at the outset, unlike Jaworski’s book, this has been far from a comprehensive assessment of the arguments for and against physicalism. It was only intended to introduce some of the evidence cited in support of physicalism (argument from past explanatory success) and some of the classic objections to the physicalist worldview (Hempel’s dilemma, The Knowledge Argument, and the problem of absent or inverted qualia).

Mind-Body Physicalism (Part Two): Hempel's Dilemma

(Part one)

This post is the second in a brief series on the basic arguments for and against mind-body physicalism. The series follows the discussion in William Jaworski’s book Philosophy of Mind: a Comprehensive Introduction . This post is subject to all the caveats and qualifications mentioned in the first post.

To recap a little, the mind-body physicalist is, at the most abstract level, committed to the view that mental reality is ultimately identical to, supervenient upon, or realized by the entities posited in fundamental physics. As we saw the last day, one argument for this thesis is the argument from past explanatory success: physicalist explanations have been successful in the past so they are likely to be successful in the future. In today’s post we’re going to consider a classic objection to physicalism: Hempel’s dilemma. This is, in fact, a specific instance of a broader problem in the philosophy of science and so has ramifications that extend beyond the mind-body problem.

Let’s see what all the fuss is about.


1. Hempel’s Dilemma
For the purposes of this presentation, I am going to reach beyond the confines of Jaworski’s book and look instead to (part of) the discussion of Hempel’s dilemma in Andrew Melnyk’s book A Physicalist Manifesto . I do so because - solid and all as Jaworski’s presentation is - Melnyk is slightly clearer about both the constraints facing the physicalist that give rise to the dilemma, as well as the subsequent implications of the dilemma. Indeed, Melnyk has a gift for clarity, rigour (and, indeed, humility) that is on display throughout his book. This gift makes his probably the best overall defence of physicalism on the market.

Anyway, Melnyk notes at the outset of his book that a physicalist need not perform any sort of conceptual analysis on the term “physical”. This is because the physicalist’s goal is not necessarily to closely track ordinary language or meaning, but instead to provide content to a thesis. Thus, it is open to the physicalist to provide an entirely stipulative definition of the “physical” and work from there. Still, even that stipulative definition will be subject to some constraints. He lists three:

(i) It cannot be obviously false : This seems like a straightforward constraint. Anyone who commits themselves to a thesis cannot also be committed to its falsity, can they?

(ii) It cannot be analytic or trivial : This seems legitimate. For example, if physicalism were simply defined as the thesis that “whatever exists is physical” it would be trivially true. It would have no possibility of being false and would say nothing interesting about the fundamental nature of reality (including mental reality).

(iii) It must have some content that is determinable now by us: This, also, seems legitimate. We cannot, it would seem, accept a theory that is devoid of currently determinable content because such a theory would have two unwelcome implications. First, it would not automatically exclude many things that we now take to be non-physical. And second, it would prevent us from taking currently available scientific evidence as evidence for or against physicalism.

Although each of these constraints is plausible, they create a bit of a problem for the physicalist. The problem is that it is impossible for an adequate definition of physicalism to satisfy both (i) and (iii) at the same time. This can be expressed in the form of an argument, as follows:

• (1) If “physicalism” is to be an adequate theory, it’s definition must satisfy three conditions: (i) it must not be false; (ii) it must not be trivial and (iii) it must have content that is determinable now by us.

• (2) “Physicalism” can either be defined by reference to the current content of physical theories or to the content of some future ideal physical theory.

• (3) If “physicalism” is defined by reference to current physical theories, then conditions (ii) and (iii) are met but (i) is not.

• (4) If “physicalism” is defined by reference to a future ideal physics, then conditions (i) and (ii) are met but (iii) is not.

• (5) Therefore, physicalism is not an adequate theory.

Now you may be wondering: what reason do we have to accept (3) and (4)? The answer is the following. We have reason to accept (3) because past experience suggests that physical theories are constantly being refined, replaced and superseded by better physical theories. So if past experience is any guide - and who are we to assume otherwise? - the content of current physical theories is almost certainly false. We have reason to accept (4) on the grounds that a future ideal physics must, necessarily, have content that is not now determinable by us, otherwise we would already be in possession of the ideal theory.

The argument contains within in it a dilemma, usually attributed to Carl Hempel: either the physicalist accepts a theory that is almost certainly false; or he accepts a theory that has no content; he can’t do both.



2. Responding to the Dilemma
I’ll switch back to Jaworski’s book now. He notes that, as with all dilemmas of this sort, there are various strategies open to the physicalist in response. They can grasp one or other of the horns and say that the implications are not as dire as they first appear; or they can deny one of the premises that gives rise to the dilemma, thereby slipping between its horns. Jaworski notes that the second strategy is - perhaps surprisingly - not all that popular (although Melnyk could actually be interpreted as opting for that approach). Instead, most defenders of physicalism have grasped one of the horns.

For instance, there are those who say that accepting a theory, even though it is likely to be proved false in the future, is not that big a deal (again, Melnyk could be interpreted as taking this approach). They take their inspiration from the fact that this is simply par for the course in physics. One defends whatever theory seems most likely to be true at a particular moment in time. This is how we progress toward better theories. There’s no real problem here.

• (6) There is no real problem associated with accepting a theory that is probably false: this follows best scientific practice.

Alternatively, there are those who accept that physicalism must be defined relative to an ideal physics. They tend to deny that a commitment to physicalism in the here and now lacks content. They’ll say current physics provides some clue as to the content of future physics. They justify this claim by pointing out that although physical theories have been refined and replaced over the past 400 years or so, the older theories are rarely deemed to be completely false. Some of the content from those theories carries over. Thus, even if physics hasn’t bottomed-out at the fundamental level of reality yet, we know enough now to say that mental entities will not exist at that fundamental level. They will, instead, be made up of components from that level.

• (7) Defining physicalism relative to an ideal future theory does not render it devoid of content.

As I see it, both (6) and (7) function as denials of (1). That is, they supply reason for thinking that a theory which fails to meet those three conditions can still be adequate. This is reflected in the diagram below.

Okay that’s it for now. In the next post we’ll consider the famous knowledge argument against physicalism.

Mind-Body Physicalism (Part One): The Argument from Past Explanatory Success

Since I did a whole series on the basic arguments for and against substance dualism, I thought it might be nice to do a symmetrical series on the basic arguments for and against mind-body physicalism. I’m sure some of my readers will like this too - they suggested as much in the comments section. As with my series on substance dualism, William Jaworski’s book Philosophy of Mind: a Comprehensive Introduction will be the source material.

It’s only right that I warn you at the outset: Although the motivation for this series is to serve the interests of symmetry, there are differences between the treatment of the two positions that will make this series on physicalism far less satisfactory than the one on substance dualism. Primarily, this is due to the fact that there has been a lot more theoretical refinement of physicalism over recent years. Indeed, such is the volume of theoretical refinements that Jaworski spends four whole chapters going over them.

I don’t wish to follow each and every refinement here - there’s no sense in producing the book as a whole - so instead I’ll just cover one basic argument for physicalism (the argument from past scientific success) and three objections to physicalism (Hempel’s dilemma, the knowledge argument, and the problem of inverted qualia). These three objections provide the springboard for the further refinements mentioned above. Some of these are impressive and the arguments in their favour can be quite compelling, but if you’re interested in these then I recommend getting a hold of Jaworski’s book (this is the last recommendation for a while - I don’t want to end up as Jaworski’s personal promoter).


1. The Argument from Past Explanatory Success
Physicalists come in many flavours, but they usually share one basic commitment: the commitment to the fundamentality of the physical sciences. That is to say, they all tend to believe that whatever reality ultimately consists in will only be properly described using the language of physics. Furthermore, that which is properly described using the language of physics is called “physical”. So since the mind is part of reality, it would seem to follow that mind must ultimately be physical.

Clearly this commitment to physics is in want of justification. This is where the argument from past explanatory success comes into play. Before discussing that argument it’s worth making something clear: there are other arguments in favour of physicalism in general and also in favour of particular forms of physicalism. Indeed, we encountered one such argument - the argument from the problem of interaction - when looking at substance dualism. But even that argument would seem to trace its authority back to the explanatory success of physics. Anyway, the argument itself takes the following form:

• (1) If explanations of type A have, in the past, been superior to explanations of type B (with respect to a broad range of subject matters), then explanations of type A are likely to be superior to explanations of type B with respect to other subject matters.

• (2) Physical explanations have, in the past, been superior to non-physical explanations with respect to a broad range of subject matters.

• (3) Mind-body relations are a subject matter in want of an explanation.

• (4) Therefore, physical explanations are likely to be superior to non-physical explanations with respect to mind-body relations.

Now this might look a little bit strange. For one thing, it doesn’t appear in this form in Jaworski’s text. He presents the argument as a straightforward {“Physical explanations have been superior to non-physical explanations in the past” → “Therefore, physical explanations are likely to best with respect to mind-body relations”} inference. His version makes the inductive gap between the premise and the conclusion transparent. I’ve tried to plug this gap by introducing an explicit inductive principle in the shape of premise (1). But this does not change the overall strength of the argument.

And this is the critical point. Inductive arguments of this sort cannot provide decisive reasons in favour of a particular conclusion. They can only provide probabilistic reasons for supporting a conclusion. The probabilities in question might be very high, but they are probabilistic nonetheless. Does this make things easier for the critic of physicalism? Not necessarily. We each of us rely on inductive principles, so the proponent of an alternative theory should be reluctant to dismiss the argument solely because it is inductive in nature. Instead, they should prefer to provide some good reason for thinking induction is unwarranted in this particular instance. Which brings us to….


2. Supporting the Argument
The key to the argument from past explanatory success is the support given to premise (2). If many impressive examples of successful physical explanations can be given, then dualists will have their work cut out. To block the induction from these case studies, they will need to show that mind-body relations are completely disanalogous to them. That’s certainly not impossible but it must be done nonetheless.

So what examples can be adduced in support of premise (2)? Jaworski offers four. Now, I’m not a historian of science so I can’t really vouch for the accuracy of each of them. They sound plausible to me but, for instance, I have no idea if people ever really did explain magnetism by appeal to non-physical spirits. Also, I would presume that the success of physicalistic explanations in each of these domains is determined by following the rules of inference to best explanation or some probabilistic alternative (Bayesian or Likelihoodist). In other words, physicalist explanations win against competitor explanations because they are simpler, afford us greater predictive and manipulative powers, confer a higher probability on the data and so on ( see this series for more ).

Anyway, the four examples are:

• (2.1) Magnetism : At one point in time people tried to explain magnetic by positing the presence of nonphysical spirits in magnetised objects. A physicalistic explanation of magnetism in terms of the electromagnetic force proved far more successful.

• (2.2) Planetary Motion : At one point people thought non-physical intelligences (gods) could account for the orbital movements of the planets. This was replaced by a far more successful physicalistic explanation of those movements by reference (initially) to Newtonian laws of gravity and (eventually) to the warping of spacetime.

• (2.3) Life : People once thought that the only thing capable of explaining the nature and behaviour of living things was by positing the existence, in them, of non-physical vital spirits. This has now been replaced by a far more successful explanation of life in terms of mechanical metabolic and reproductive processes.

• (2.4) Mental Illness Abnormal human behaviour was once explained by reference to possession by non-physical beings. Now many (if not all) such abnormalities can be explained by reference to tissue pathologies or alterations in the electrical and chemical balance of the brain.

We can plug these four examples into the argument and then map it out as follows.

Now as has been stressed already this argument is far from watertight. We’ll consider the various problems with it, and with physicalism as a whole, over the remainder of this series.

Substance Dualism (Part Five): Explanatory Impotence

(Part one, Part two, Part three, Part four)

This is the last in a series of posts on substance dualism. The series has been following the discussion in William Jaworski's book Philosophy of Mind: a Comprehensive Introduction. Having initially addressed the basic argument for substance dualism, we have more recently been concerned with three problems that the substance dualist must confront. Two of these have already been outlined. In this post, the third problem - that of explanatory impotence - will be discussed.




1. Inferences to Best Explanation
If substance dualism is true, then we (persons/minds) can exist without bodies. But if we can exist without bodies, then why is it that we all seem to be attached to a body? If the mind-body relation is not a necessary one, then surely some explanation of this correlation is in order? Aristotle posed this very challenge to the dualist back in the day, and it speaks to an interesting line of criticism - one which crops up again and again in the mind-body debate.

The line of criticism in question - in this case directed at the substance dualist - proposes that if a given theory is a poor explanation of the data that needs to be explained, then it can be dismissed in favour of a better explanation.

This brings us to the concept of inference to best explanation (a concept discussed on this blog before) and the correlative concept of inference from a worse explanation. Both work with abductive arguments and, following Peirce's classic schema, look something like this.

• (1) H is some data in want of an explanation.

• (2) E, if true, would account for H.

• (3) E is a better/worse explanation than all other rival explanations (E1....En).

• (4) Therefore, E is probably/probably not true.

Formally, this kind of inference commits the fallacy of affirming the consequent. The comparative exercise undertaken in the third premise, combined with the probabilistic nature of the conclusion, is designed to overcome this problem.


2. Is Substance Dualism a Worse Explanation?
The charge here is that substance dualism, when compared to its rivals, is a worse explanation of the available data, and should therefore be dismissed. How is this charge sustained?

First, consider the data that any theory of mind needs to explain. We've already pointed to one element of that data: the apparently steadfast connection and interaction between minds and physical bodies. But the data is more nuanced than that. For one thing, not just any physical body appears to have a mind: only certain evolutionarily recent organisms have that honour. What's more, mental activity is only correlated with certain parts of those organisms: brains and nervous systems, not hairs and fingernails. How do substance dualists account for these particular correlations?

The answer is that they don't appear to be able to do so. In fact, it is in their interests to show that the connection we observe is apparent rather than real. After all, they want to show that there is no essential connection between mind and body.

This highlights a curious feature of the dialectic between substance dualists and their critics. The critics will want to argue that since other theories of mind do account for the puzzling mind-body correlations outlined above, they are stronger and more rationally compelling. The substance dualists will want to argue that a theory which explains mental-physical correlations has no advantages over its rivals. The correlation can either be dismissed as irrelevant or accepted as a brute fact.

Thus, there appears to be real gap between the two sides over what needs to be explained by an acceptable theory of mind. Alas, gaps of this sort frequently emerge in philosophy.


3. Conclusion
In summary, the problem of explanatory impotence may have some force, but this depends on the data we think warrants explanation. I personally feel that the kinds of mind-body correlations discussed by Jaworski merit explanation. Consequently, I would would be disinclined to accept a theory that dismissed them. To shift from this position, I'd need to be convinced that substance dualism had other epistemic advantages. Since that seems unlikely given the other posts in this series, substance dualism is perhaps best left to one side.

All that said, a recent tactic among some proponents of substance dualism is to point out that even if the arguments in its favour are not all that strong, they are no worse than the arguments put forward in defence of, say, physicalist theories of mind. Thus, to cling to substance dualism is no less rational than to cling to physicalism.

Substance Dualism (Part Four): The Problem of Interaction

(Part One, Part Two, Part Three)

I've been addressing arguments for and against substance dualism over the past week. In the most recent post on the topic, I considered the first of three arguments against the theory. In this post, I turn to the second of those three argument: the argument from the problem of interaction. In the course of addressing this problem we will encounter some possible refinements of the substance dualist position.



1. The Problem of Interaction
This morning I did something unusual. I decided to write a blogpost on substance dualism: I formulated the intention and then followed through on it by executing the series of bodily movements referred to as 'typing'.

But wait a minute, there's nothing unusual about this is there? Surely we do things like that all the time, i.e. formulate intentions and then carry them out by executing a series of bodily movements? Yes, you're quite right; there's nothing unusual about this in and of itself. But it is quite unusual from the perspective of substance dualism.

The difficulty can be stated in the form of an argument:

• (1) If substance dualism is true, persons cannot causally influence bodies.

• (2) Persons can causally influence bodies.

• (3) Therefore, substance dualism is false.

Once again, it is the first premise that is the main source of controversy here. What can be said in its favour?


2. The Physical Basis of Causation
Quite a lot can be said in favour of premise (1). To see this, we need to bear in mind the ontological commitments of the substance dualist. Remember, they argue that mental entities can exist wholly apart from physical entities; and that physical entities can exist wholly apart from mental entities.

This creates a problem when mental entities are thought to be causing changes in physical entities, as is the case in the intention example given above. You see, everything we know about causation suggests that in order for changes to be caused in a physical object (or for a physical "event" to be brought about) the entity causing those changes must possess two key properties: (i) a spatial location and (ii) the ability to transfer energy. For in the process of physical causation, energy is being transferred from one location to another.

Jaworski uses the example of the combustion engine to illustrate this point. In order for your car to be propelled forward, the following sequence of events must take place: spark plugs in the engine must be ignited by a high-voltage pulse; the ignition of the spark plugs must release energy from the gasoline (petrol) by combustion; the energy from the gasoline must drive the pistons; and they in turn must drive the crankshaft, which drives the axle, which turns the wheels. Each stage in this process involves energy transference from one spatial location to another.

Here then is a serious problem for the substance dualist. Both of the key properties for causation are physical in nature, indeed they are perhaps the very essence of the physical. They are not possessed by mental entities.

So:

• (4) Bodies are physical entities.

• (5) Only entities with a spatial location and the ability to transfer energy can cause changes in physical entities.

• (6) According to substance dualism, persons have neither spatial locations nor the ability to transfer energy.

• (1) Therefore, if substance dualism is true, persons cannot causally influence bodies.

3. Substance Dualist Responses
With premise (1) now fully defended, the problem of interaction seems to be robust. How can the substance dualist respond? There are several possibilities, some of which lead us towards more refined versions of substance dualism.

Let's consider the less-refined rebuttals first. One is to simply reject premise (1) (or, more precisely, premise 5) and argue that non-physical causation is intelligible, or at least no less intelligible than purely physical causation. The idea here is that the ability of physical entities to cause changes in one another is basically an inexplicable brute fact. We simply have to accept it as a given. So why not accept the ability of mental entities to cause changes in physical entities as a similarly brutish fact?

One problem with this line of response comes from the law of conservation of energy. It is a basic principle of physics that the amount of energy in a closed system is fixed: add up the total energy before and after an event in such a system and you will get the same figure; energy is simply moved around from one location to another. If mental entities were causing physical events then we would expect energy to be added to the relevant system (in this case the human body and its surrounding environment) from outside. This would require a violation of the conservation law that does not appear to take place.

We can map this exchange out as follows:

• (7) If physical-physical causation is accepted as a brute fact, so too can mental-physical causation be accepted as a brute fact.

• (8) Mental-physical causation would involve the violation of the conservation law of energy, this law does not appear to be violated.

This argument effectively presents the substance dualist with a dilemma: they can either have mental-physical causation or the laws of physics, they cannot, or so it seems, have both.

It should be noted in passing that in addition to being part of an argument against substance dualism, the conservation law of energy is often used to support mind-body physicalism.


4. Parallelism and Occasionalism
If rejecting premise (1) seems too much to bear, the substance dualist can always reject premise (2). This would mean a rejection of the apparent causal relationship between mental entities such as intentions and physical acts such as bodily movements. Such a rejection would leave us with the unexplained fact that mental entities seem to be very closely correlated with certain physical acts. How, we must ask the dualist, can this be the case?

In answering this question, the substance dualist will be forced to introduce one of two possible refinements to their original position. The first possible refinement is called "parallelism"; the second is called "occasionalism".

Parallelists believe that mental and physical systems, although ontologically distinct, run in parallel to one another. This creates the impression that events in one system are causing changes in the other system, but this is purely coincidental.

An analogy with clocks is often used to illustrate the point. Suppose you have two clocks, A and B. Both are wound up at the same time (remember when you had to wind-up clocks?) and thus run in synchrony. Now suppose you remove the chimes from clock A and the hands from clock B. As a result, clock B will appear to chime when clock A's hands arrive at a particular time. This might create the impression of a causal link between the two clocks but that is all it is: an impression. There is no real causal link. Something analogous could be taking place between the mind and the body.

Parallelism is certainly a possibility, but how plausible a possibility is another question. In the clock analogy we have an explanation for the parallelism; in the mind-body example we have no such explanation. Thus, accepting parallelism would seem to require accepting a significant, inexplicable coincidence. Sort of like the coincidental relation between epistemic faculties and moral truths proposed by some moral realists. This seems like a big pill to swallow just to save the substance dualist worldview.

• (9) The mental and physical system may simply be running in parallel, thus creating the impression of a causal link between them.

• (10) Accepting parallelism would force us to accept a significant coincidence as a brute fact, we should be reluctant to do so unless there are other compensating benefits.

An alternative way in which the substance dualist can reject premise (2) is by adopting an occasionalist view of mind-body causation. According to this view, God acts as a causal middleman producing changes in the physical body that correspond to changes in the mind.

Leaving aside any challenge to the explicitly theistic grounding for this view, there are two objections that need to be considered. First, it has the strange consequence that God is the only real agent in existence, i.e. the only one that can bring about changes in the real world that deserve to be called "actions". This has a further consequence. Agency is an essential precondition for moral responsibility. So if none of us are really agents, then none of us are ever morally responsible. That will strike many as absurd.

Finally, the theory has the unenviable whiff of ad-hocery about it. In other words, the supposition that God acts as a causal middleman is being adopted purely to save face. It is generally agreed that the acceptance of ad hoc principles of this sort is to be avoided.

• (11) God could act as a causal middleman between persons and bodies.

• (12) The assumption that God acts as causal middleman: (i) leads to the absurd conclusion that God is the only agent; and (ii) is ad-hoc.

5. Conclusion
In the end, it seems like the problem of interaction forces the substance dualist into an uncomfortable corner. They can manoeuvre their way out it, but only by accepting some epistemically costly doctrines. They need to ask themselves whether the commitment to substance dualism is really worth these costs.

Substance Dualism (Part Three): The Problem of Other Minds

(Part One, Part Two)

Substance dualism has been preoccupying me over the past week. In the two previous posts, I've looked at the basic argument for it, as well as the criticisms of that argument. In this post, I'll consider the first of three arguments against substance dualism: the argument from knowledge of other minds. Once again, William Jaworski's excellent book is the source for this post.



1. Introduction to the problem
Jim and Pat are housemates. Jim is sitting in the kitchen one afternoon when Pat arrives home. He has been out jogging. Seeing Jim, Pat gestures vaguely at the sink before placing his hands on his knees and starting to pant. Jim understands. He takes a glass from the cupboard, walks over to the sink, and pours Pat a glass of water. Pat takes it and thanks Jim.

What has just happened? Put simply, Jim read Pat's mind: he inferred that Pat desired a glass of water from Pat's body language. There's nothing unsurprising about this either: Mind reading exercises of this sort would appear to be a commonplace.

But these commonplaces create a problem for the substance dualist. The problem can be expressed in terms of the following argument:

• (1) If substance dualism is true, then we cannot know the mental states of others.
• (2) We do, on at least some occasions, know the mental states of others.
• (3) Therefore, substance dualism is false.

I would expect premise (1) to be the major bone of contention here. So developing a more persuasive argument in its favour is our first port of call.


2. The Argument for Premise One
Why is the substance dualist committed to premise (1)? The answer has to do with the presuppositions that make mind-reading possible. For Jim to infer Pat's state of mind from his behaviour, he has to assume that there is some consistent connection between physical indicators such as body language and the mind. We could call this the assumption of the "mental code". The problem is that the substance dualist cannot assume the existence of such a code.

To see why this is the case, we have to remember the ontological commitments of the substance dualist. They believe that mental entities can exist without any physical substrate or grounding; and that physical entities can exist without any mental accoutrements. This, as you recall, is one of the key premises of their basic argument. But it has the unfortunate consequence that there need not be a mental code because it implies that there is not necessarily a consistent connection between physical indicators and mental states.

Jaworski illustrates the point as follows. Consider a human body and a table. We traditionally assume that one mind is associated with the human, but not with the table. But in the substance dualist worldview other relationships between mind and body are equally plausible: there could be several minds associated with the body, there could be a mind associated with the table, there could be no mind associated with either the body or the table, or there could be a mind associated with the body-table collection. All such things are made possible because the physical can be explained entirely without reference to the mental and vice versa.

This gives us the following argument

• (3) For knowledge of the mental states of others to be possible, there must be a reliable connection between certain physical indicators and mental entities.

• (4) If substance dualism is true, there is no reliable relationship between the mental and the physical.

• (1) Therefore, if substance dualism is true, we cannot know the mental states of others.

3. The Substance Dualist Response
The substance dualist is far from finished. Certain responses are available to him or her. For starters he or she can accept premise (1) and dispute premise (2). After all, our primary grounds for accepting premise (2) are a combination of intuition and tradition, neither of which would seem a reliable guide to truth. So we could easily reject premise (2).

But look at it this way: (2) is part of our intuitive, pre-theoretical worldview. We can, indeed, cast off elements of our pre-theoretical worldview, but only if we have compelling reasons to do so. For instance, that heavier objects fell faster than lighter objects might have seemed obviously true at one point in time. But we now have compelling reasons - both logical and empirical - for rejecting that belief. The question is whether similarly compelling reasons can be offered in favour of substance dualism. We have already evaluated the basic argument and found it somewhat lacking. So hanging onto premise (2) would seem like the better bet.

We can spell out this little exchange as follows:

• (5) Our belief that we can know the minds of others is part of our intuitive, pre-theoretical worldview - this is not a reliable guide to truth.

• (6) We should only discard parts of our pre-theoretical worldview if we have compelling reasons to do so - such reasons do not exist in the case of substance dualism.

Are there any other responses available to the substance dualist? Indeed there are.

Go back now to premise (1). We offered what seemed to be a persuasive argument in its favour, but that argument may have made some unwarranted assumptions. Two in particular seem relevant.

First, we assumed that the only way to know the minds of others was through inference from observed physical indicators. The dualist can argue that there are others ways in which to acquire knowledge of other minds. They could argue that individual minds are directly linked to one another in the manner envisaged by proponents of ESP. This is a difficult claim to evaluate but it would appear problematic. For starters, the evidence on ESP is patchy at best. And what’s more, even if some people have ESP, it’s pretty clear that others don’t. I know, for example, that I don’t but I still think I can, on occasion, know what other people are thinking by inferring it from their physical behaviour. So it would seem like the problem will remain even if ESP is a reality. Let’s formulate some premises on this:

• (7) Inference from physical indicators in not the only way to know the minds of others; we could acquire such knowledge through, for example, ESP.

• (8) Evidence for ESP is patchy at best; furthermore people who don’t have ESP still appear to, occasionally, know the minds of others solely by inference from physical indicators.

Second, we assumed that, in the substance dualist worldview, all possible relations between the mental and the physical were equally plausible. This need not be the case. The dualist could argue that we have good evidence for thinking that the one-mind-for-every-human-body-relation is the most plausible. How so? Well, you know that that relation applies to you so you can, by inductive inference, argue that it holds for all human bodies. But this won’t do. Inductive inferences are only warranted if the inference is made from a reasonable sample size. A sample of one would seem insufficient.

• (9) The substance dualist can, by inductive inference, argue that the one-mind-for-every-human-body-relation is the most plausible.

• (10) This inference is not warranted because the reference sample is too small.

4. Conclusion
The problem of knowledge of other minds is a serious one for the substance dualist. They are not entitled to assume the existence of mental code because of their ontological commitments. Furthermore, although our knowledge of other minds would seem to be part of our pre-theoretical worldview - and so, not necessarily true - we would need compelling reasons for casting it off. The substance dualist has not yet provided them.

Substance Dualism (Part Two): Criticisms of The Basic Argument

In the previous post, I summarised William Jaworski’s presentation of the basic argument for substance dualism. In this post, I’ll be covering Jaworski’s discussion of the criticisms of that basic argument. Remember, substance dualism is a time-honoured position within the philosophy of mind and it’s well worth knowing why some find it persuasive and others do not.

As we saw the last day, the basic argument for substance dualism relies on two premises. The first of those premises derives from the axioms of identity and is relatively uncontroversial. The second of those premises makes a modal claim. It says that we (i.e. minds/persons) can exist without bodies. This claim is controversial and is supported by two equally controversial arguments: (i) the conceivability-possibility argument; and (ii) the essential property argument. Both were discussed in part one. Now we turn to the criticisms of both those arguments.



1. What can we actually conceive?
Let’s focus on the conceivability-possibility argument first. As we know, this argument has the following form:

• (2.1) If it is conceivable that x can exist without y, then it is possible that x can exist without y.

• (2.2) It is conceivable that we could exist without bodies (including brains).

• (2) Therefore, we can exist without bodies.

There are obviously two points of attack here: premise (2.1) or premise (2.2). We’ll take these in reverse order.

Premise (2.2), as pointed out in part one, can be supported by three examples. Each of these examples purports to demonstrate that we can conceive of our existence without a body. The first example asks us to imagine existence in the after life; the second example asks us to imagine watching our own bodies being annihilated; and the third example asks us to imagine we are victims of a Cartesian Demon.

In the initial presentation we assumed that these examples really did involve the conception of a mind existing without a body. This time round we need to be more critical. Have we really thought about each example in sufficient and vivid detail to be sure that we can conceive of our own existence without the presence of a body? This is a serious question: if our imaginings are superficial and vague, we may only be conceiving of the partial absence of a body not its complete absence.

Consider the annihilation example (see description in previous post) and ask yourself: can you really conceive of yourself watching your body being annihilated? How do you suppose you receive the necessary visual input? Can you really imagine receiving it without any eyes?

Buried amongst these rhetorical questions we have our first attack on (2.2):

• (3) Our imagining of the possibilities might be too vague and superficial to count as true conceivability.

Substance dualists can respond by saying only clear and distinct conceivability counts. This is acceptable but in that case it’s much less obvious that examples of the sort presented in the last post pass the test of conceivability.


2. Is the Conceivable really Possible?
Let’s turn our attention to premise (2.1) now. This premise proposes that conceivability is a reliable guide to possibility. Is this correct? Can our imaginations really tell us what obtains in different possible worlds? Well, it all depends on the type of possibility we are concerned with. Conceivability might be a reliable guide to some forms of possibility and not to others.

Jaworski orients his discussion around three types of possibility:

Technological Possibility: P is technologically possible if and only if P is consistent with current technological constraints.

Physical Possibility: P is physically possible if and only if P is consistent with the laws of physics.

Metaphysical Possibility: P is metaphysically possible if and only if P is consistent with itself.

These three types of possibility are very different from one another. It is technologically impossible (right now) to cure cancer, but this does not mean that it is physically impossible to do so. And it is physically impossible for there to be a 1000kg uranium sphere, but this does not mean that such an object is metaphysically impossible. There’s nothing internally inconsistent about the concept: if the laws of physics had been different, such an object could exist.

Conceivability is likely to be a poor guide to technological and physical possibility. Both concepts depend heavily on the current state of our empirical knowledge. We can’t now conceive of the technology that will cure cancer (if we could, we would simply invent it) but we might in the future be able to conceive of it. Likewise, being able to conclusively say that something is physically impossible depends on knowing all the laws of physics. But every physicist knows there are gaps in the current laws that need to be filled. It is empirical discovery, not a priori thought experiments, that flesh out our understanding of technological and physical possibility.

What then of metaphysical possibility? This is the brand of possibility to which the substance dualist appeals. Can he or she say, definitively, that non-material existence is possible solely on the basis of a thought experiment?

There do appear to be occasions on which a priori methods tell us something about metaphysical possibility. For instance, the rules of logic tell us that it is impossible for a married man to also be an unmarried man. Such a statement is self-referentially inconsistent. In a similar vein, the rules of semantics tell us that it is impossible for a bachelor to be married. Such a statement is analytically true.

If the independency of mind and body were simply a logical or analytical truth, the substance dualist might be home and dry. But this need not be the case. For there is a third type of metaphysical possibility that does seem to depend on empirical evidence. The classic example is the identity relation between “water” and H2O. This is thought to be a metaphysically necessary relation, but one that was only established through empirical investigation of the referent of the term “water”. (see Twin Earth thought experiments for more). If the relation of mind and body is like that of water and H2O, then a priori methods are insufficient to prove what needs to be proved.

So we come to the crux of the problem for the substance dualist:

• (4) While conceivability might be a reliable guide to some types of metaphysical possibility, it is not a reliable guide to all types. Furthermore, it might be that the mind-body relation is a type of metaphysical necessity that can only be established through empirical investigation.

3. The Essential Property Argument
We turn now to the criticisms of the essential property argument. As we recall, the argument looked like this:

• (2.3) An object, event or state of affairs can exist without its accidental properties; it cannot exist without its essential properties.

• (2.4) Having a body is a strictly accidental property of beings like us.

• (2) Therefore, we can exist without bodies.

Premise (2.3) is unobjectionable; premise (2.4) is more dubious. Last time out, we saw that there were two methods for establishing what counted as an essential property and what counted as an accidental property: (i) the conceptual method and (ii) the empirical method. The former was used by the substance dualist and was the basis on which (2.4) was reached.

It is time to call that method into question. Continuing with the line of thought established above when looking at metaphysical possibility, we can argue that conceptual thought experiments are an insufficient test for whether a property is essential or accidental. The water example can be called to assist us in making this point: a purely conceptual analysis would not have revealed that the essence of water is H2O -- empirical investigation was needed for that. Discovering the essential properties of persons or minds might require similar empirical investigation.

This brings us to a second critique of the essential property argument. According to this critique, the argument begs the question against physicalism. The reasoning behind the critique is as follows. Most will agree (substance dualists included) that if something is physical in nature, then only physics can give us the final word on its properties (essential or otherwise). But then this implies that if persons are physical, then only physics can give us the final word on their essential properties. The essential property argument assumes that the conceptual method can determine the essential properties of persons. Thus, the argument must be assuming that persons are non-physical. Therefore, it begs the question.

There is one final criticism of the argument. This was originally noted by Descartes’ contemporary Antoine Arnauld. Arnauld pointed out that, even if conceivability is a guide to metaphysical possibility, we can often fail to initially recognise all the properties that an object possesses. For instance, before the advent of electromagnetic theory, if we were listing all the properties of an object, we would have missed out on most (if not all) of its electromagnetic properties. After the advent of electromagnetic theory, we would have had a greatly enriched understanding of the properties possessed by the object.

So following Descartes’s procedure might lead us to miss out on some of the essential properties possessed by an object. We might also fail to appreciate the necessary connections between some of those properties. Applying this to the mind-body problem, following Descartes might lead to an impoverished understanding of the essential properties of a person.

We can summarise these three criticisms as follows:

• (5) The conceptual method is insufficient for establishing the essential properties of all objects.

• (6) The reliance on the conceptual method is question-begging.

• (7) Descartes’s procedure may lead us to miss out on some of the essential properties of persons.

The completed map for all the criticisms of the second premise of the substance dualist argument can now be drawn up.

4. Moving forward
To this point in the discussion we have been focused on the basic argument for substance dualism and rebuttals to it. In the next post, we’ll start to consider the reasons for thinking substance dualism is false.

Substance Dualism (Part One): The Basic Argument

Substance dualism is an enduring theory within the philosophy of mind. According to substance dualists the mind is ontologically distinct from the body.

With the rise of neuroscience in the 19th and 20th centuries, the theory appeared to become less tenable: the evidence seemed to point, overwhelmingly, toward a deep connection between mind and brain. But despite the continued presence of this evidence, a satisfactory theory of mind-brain relations remains elusive. As a result, my current sense is that substance dualism may be due to undergo something of a recrudescence. Thus, those of us with an interest in the philosophy of mind would be well-advised to understand the arguments that can be mustered in its support.

Fortunately, William Jaworski, through the medium of his recent book Philosophy of Mind: a Comprehensive Introduction, is on hand to assist. I’ve mentioned and recommended this book before. In this post, I will run through Jaworski’s presentation of the basic argument in favour of substance dualism. In future posts, I’ll consider the various criticisms and responses to this argument.



1. The Basic Argument for Substance Dualism
As is the case with many of the most intractable philosophical arguments, the argument for substance dualism can be stated with admirable brevity. [Note: In the argument “we” just means “persons or minds”]:

• (1) If we can exist without bodies, then we cannot be bodies.
• (2) We can exist without bodies.
• (3) Therefore, we cannot be bodies.

As Jaworski notes, this is often called the modal argument for substance dualism. It garners this name because it appeals directly to the possibility of a mind or person existing without a body. Possibility is, of course, a modal concept.

The argument as stated is valid, but its two premises are in need of support.


2. The Argument for Premise 1
The first premise makes a simple identity-based claim. As such, it is relatively easy to defend it by appealing to the axioms of identity.

Identity is a relation of sameness or equivalence between two objects, events or states of affairs. In other words, x is said to be identical to y, when the labels “x” and “y” can be used to refer to the same object, event or state of affairs. Thus, we can say that February 14th is identical to Valentine’s day because those labels refer to the same day; or that “Samuel Clemens” is identical to “Mark Twain” because both labels refer to the same person.

So if x and y are identical, they must be the very same object, event or state of affairs. In that case, x cannot exist without y. Why not? Because to say that x exists but y does not would be to deny the identity relationship that was originally presumed.

Applying this to the mind-body debate we can say the following. If, as some physicalists claim, the mind and body (or, at a minimum, a defined proportion of the brain) are identical, then one cannot exist without the other. And contrariwise, if the mind and body are not identical, as substance dualists claim, then one can exist without the other.

To lay this out more formally:

• (1.1) If x and y are identical, then x cannot exist without y; but if x and y are not identical, then x can exist without y (axioms of identity).

• (1.2) Therefore, if we are identical to our bodies, then we cannot exist without them; but if we are not identical to our bodies, we can exist without them.

• (1) Therefore, if we can exist without our bodies, then we cannot be bodies.

Jaworski notes that there is nothing to really dispute in this line of reasoning. So if there is a problem with the substance dualist argument, it is unlikely to be found through a critique of premise (1). Premise (2) must be where all the action is. And there are two arguments in its favour to be considered.


3. The Conceivability Argument for Premise 2
Premise (2) states that it is possible for the mind (for “us”) to exist without the body. But how can we say this with any confidence? One way would be to rely on a conceivability-possibility principle (a “CP” for short). A CP states, roughly, that if it is conceivable that x is true (or false) then it is also possible that x is true (or false). Since premise (2) relies on a claim about what is possible, a CP can then form the basis of the following type of argument in its favour:

• (2.1) If it is conceivable that x can exist without y, then it is possible that x can exist without y.

• (2.2) It is conceivable that we could exist without bodies (including brains).

• (2) Therefore, we can exist without bodies.

We won’t be evaluating this argument right now (we’ll leave that ‘til the next post), but we do need to ask what kind of examples can be adduced in support of (2.2). Jaworski identifies three:

(2.2.1) The Afterlife Example: Many people can conceive of themselves existing after they die (this is true even of those who don’t believe in the afterlife). But once they die, the physical body is destroyed. Therefore, in order to conceive of the afterlife these people must tacitly conceive of their existence without their bodies.

(2.2.2) The Annihilation Example : Imagine you are watching yourself sitting reading your computer screen through some security camera feed. Now imagine that the body you see sitting reading the computer is instantaneously annihilated and you are left staring at an empty chair. You are now conceiving of yourself existing without a body.

(2.2.3) The Cartesian Demon Example: Follow Descartes‘ sceptical procedure. Suppose that all your visual, auditory, olfactory and other sensory experiences are the product of a deception. By doing so, you’ll find that you can doubt the existence of the external world, including your own body, but that you cannot doubt your own existence. Thus, once again, you can conceive of your own existence in the absence of a body.

There are serious questions to be asked about these examples and whether they actually establish what they need to establish. We’ll leave those to one side for the time being and move on to consider the second argument in favour of premise (2).


4. The Essential Property Argument for Premise 2
Objects, events and states of affairs have properties. These properties come in two major forms: the essential and the accidental. An essential property is a property that an object, event or state of affairs cannot be without; an accidental property is one that it can be without.

To give an example, three-sidedness is a property that a triangle cannot be without. A triangle cannot be said to exist if it only has two sides. Therefore, three-sidedness is an essential property of a triangle. In contrast, “my favourite shape”-ness is an accidental property of a triangle. Triangles presumably existed before I was born and so did not require the property of being my favourite shape in order to exist.

The essential/accidental property distinction can be used as the basis of the following argument in favour of (2):

• (2.3) An object, event or state of affairs can exist without its accidental properties; it cannot exist without its essential properties.

• (2.4) An essential property of beings like us is that of thought or thinking; having a body is a strictly accidental property of beings like us.

• (2) Therefore, we can exist without bodies.

This argument owes its origins to the work of Descartes. The crucial premise here is (2.4). For it to be true, we need to have some reliable procedure for identifying what is an essential property and what is an accidental property; and we need that procedure to lead us to the claim stated in (2.4).

Jaworski points out two methods for identifying essential and accidental properties. One is the method proposed by empirical essentialists. They believe that the essential properties of an entity can only be identified after an exhaustive empirical study of that entity. The alternative method is that proposed by conceptual essentialists. They believe an a priori thought experiment can reveal what is essential and what is not.

Following the lead set by Descartes, the conceptual method is generally preferred by substance dualists. Jaworski describes the method as follows:

“According to Descartes, if we want to discern the essential properties of some object, A, we start by compiling a list of all the properties we take A to possess. Suppose, for instance, that P1, P2, P3...Pn is a list of those properties. We next take each property on the list, and consider whether it is possible for A to exist without it...[If] we cannot conceive of A existing without P1, then we can conclude that P1 is an essential property of A, that A needs P1 to exist. By following this procedure for every property on the list, Descartes thinks, we arrive at a list of A’s essential properties.” (pp. 42-43, with some emendations).

Following this method, we should find that having a body is a strictly accidental property of beings like us.

I know I said I’d hold off on criticisms and evaluations until future posts, but I can’t help but point out that this conceptual method seems to make the essential property argument either circular or indistinguishable from the conceivability-possibility argument. It would seem to do the former by making a claim about what it is possible for an entity to exist without dependent on a set of claims about what it is possible for an entity to exist without; and it would seem to do the latter by making what it is conceivable for an entity to exist without determinative of the essential properties of that entity.

To be fair, Jaworski is aware of these points, as is clear when he discusses the criticisms of the argument. I’ll look at these next time round. For now, I simply present a complete map of the argument for substance dualism. As always, click on the image to see a larger version.

Philosophy of Mind: Mapping the Theoretical Space

If you’ve any interest in the philosophy of mind, I highly recommend picking up a copy of William Jaworski’s recently-released Philosophy of Mind: a Comprehensive Introduction. It does exactly what it says on the tin. It provides detailed, but not overwhelming, coverage of all the major theories and arguments in the field. I’d say it might be heavy going if you’re a complete newcomer to the topic, but if you’re familiar with it it’s definitely one way to seriously bump-up your knowledge.

One of the particularly nice things about the opening chapter of the book is Jaworski’s attempt to map the theoretical space within the philosophy of mind. In other words, his attempt to delineate and organise all the different theoretical positions on the nature of the mind. To give you a flavour of the book, I’m going to summarise this cartographic exercise.

At the most general level, theories about the nature of the mind can be separated into three categories: (i) monistic theories; (ii) dualistic theories and (iii) non-standard theories. Let’s look at each category in more detail.


1. Monistic Theories
The philosophy of mind is motivated primarily by the desire to resolve a number of mind-body problems. I’ll look at these in a future post. For now, all that needs to be known is that these problems generally concern the appropriate relation between our understanding of the physical world of scientific description and our understanding of the mental world of first-person description.

Monistic theories propose that the distinction between the physical and mental worlds is ultimately illusory: they are both, fundamentally, made up of the same kind of stuff. But what kind of stuff? There are three theories to contend with:

Idealism: This theory maintains that everything is ultimately mental. That our supposition of an external physical world is merely the result of an elaborate way of describing subjective mental experiences. 

Neutral Monism: This theory maintains that everything is ultimately made up of a neutral substance that is neither physical nor mental. But this substance can be described in physical or mental terms. 

Physicalism: This theory maintains that everything is ultimately physical. That our subjective mental experiences can ultimately be redescribed in physicalistic terms.

Of these three, it is physicalism that has been subjected to the most refinement in the past 50 years or so. Thus we are forced to further distinguish between a number of physicalist theories:

Eliminative Physicalism: This theory maintains that a complete physicalist theory of reality will ultimately eliminate the need to refer to the mental. Our mentalistic vocabulary is just a folk theory that needs to be replaced.

Reductive Physicalism: This theory maintains that mental facts are ultimately reducible to physical facts, but this does not mean all reference to the mental is somehow redundant or unimportant. There are two subdivisions within this theory (actually there are even more, but there’s no need to get too fine-grained when you’re starting out): 

• (a) Behaviourism: mental facts are reducible to facts about behaviour; 

• (b) Identity Theory: mental facts are reducible to facts about the brain.

Non-reductive Physicalism: This theory maintains that although everything could ultimately be described by physics, the special sciences (psychology, sociology etc.) have descriptive and explanatory interests that cannot be fulfilled by physics. These interests are satisfied by the use of mentalistic descriptions. There are three sub-divisions within this category of physicalism: 

• (a) Realisation Physicalism: Mental phenomena are realised by physical phenomena. Indeed, they can be realised by multiple kinds of physical phenomena. 

• (b) Supervenience Physicalism: Mental phenomena supervene upon physical phenomena. 

• (c) Anomalous Monism: All events are describable in physical terms; but some events are also describable in mental terms. The psychological explanations that use these mental terms are, however, not law-like (a - nomos, without law).

The descriptions of these different positions are exceptionally brief. As a result, it might be difficult to fully appreciate the distinctions between some of them.


2. Dualistic Theories
Dualistic theories adopt the same basic tagline: the distinction between the mental and the physical is real. Where they disagree is over the precise nature of that distinction:

Substance Dualism: This theory maintains that there are ultimately two kinds of stuff: mental stuff and physical stuff. Our minds, obviously, are made up of the former, not the latter. 

Dual Attribute Theory: This theory maintains that there is ultimately only one kind of stuff but some of this stuff exemplifies irreducible mental properties that are not captured by physical explanations. This position is sometimes referred to as “property dualism” but Jaworski prefers the dual-attribute moniker for reasons presented in his chapter on this theory (mainly, because substance dualism is also committed to a kind of property dualism).

As was the case with physicalism, most of the philosophical action has been associated with one of these theories over the past 50 years or so. The theory in question is Dual Attributism, which can be broken down in the following manner:

Organismic DAT: This version of dual attributivism maintains that the kinds of entities displaying mental attributes are physical organisms. This theory can, in turn, be split in two: 

• (a) Emergentism: This theory maintains that mental properties emerge from or are caused by physical phenomena and that these mental properties can play an actual role in physical reality. 

• (b) Epiphenomenalism: This theory maintains that mental properties emerge from or are caused by physical phenomena, but that these mental properties play no causal role in physical reality.

Non-organismic DAT: This version of dual attributivism maintains that the kinds of entities displaying mental attributes might have some physical components, but are not organismic. This is a somewhat obscure position and is similar to substance dualism.

3. Non-Standard Theories
Finally, we come to non-standard theories. These theories reject one or more of the key assumptions upon which the standard theories are premised. Three such theories are mentioned by Jaworski.

Instrumentalism: This theory rejects the realist assumption of the standard theories. According to this assumption the mental predicates we use are intended to pick out objects, events and states of affairs in the external world. Instrumentalism rejects this by maintaining that these predicates are merely tools used to predict human behaviour. 

Hylomorphism: This theory rejects the mental-physical distinction-thesis that is assumed by the standard theory. According to this thesis, there really are two vocabularies used to describe and explain human behaviour. Monistic theories may think the two can be reduced to one, and dualist theories may think they cannot, but they both agree that the vocabularies exist. Hylomorphism does not. It maintains that their is a unique vocabulary for describing and explaining human behaviour. One interesting feature of Jaworski’s book is his defence of the claim that hylomorphism is a distinct theory. 

Mind-body Pessimism: This theory rejects the optimism underlying the standard theories. That optimism encourages proponents of the standard theories to believe that their theory can give a satisfactory account of mind-body relations. This theory maintains that we may forever by cognitively closed-off from such a satisfactory account.