Why the Mary Argument Fails

WHY THE MARY ARGUMENT FAILS                Colin Mitchell     June 2009

 

Abstract:  I argue that the Mary argument (and Knowledge arguments in general) do not succeed in demonstrating that qualia (and conscious experiences in general) cannot be physical facts.  Then I investigate the source of our intuition that qualia cannot be physical facts.  By means of a thought experiment I show that the hypothesis that qualia are identical with brain processes is a reasonable one.  

 

The Mary argument is the best known form of what is generally known as the Knowledge argument.  The Knowledge argument asserts that full knowledge of the physical facts of brain processes is insufficient to enable us to know what it is like to experience qualia (or conscious experiences in general) and that therefore qualia (and conscious experiences in general) cannot be physical facts (or at least not the physical facts of brain processes).  Qualia are the ‘quality’ of mental states or perceptions as they are immediately perceived by the individual having them – the ‘what it is like’ of experiences – particularly applied to sensory experiences.

 

The Mary argument was proposed by Frank Jackson in an article in 1982 under the heading “The Knowledge Argument for Qualia” (Jackson 1982).    Mary is a neuroscientist specialising in the neurophysiology of vision and knows all there is to know about the physical facts involved in the perception of colour.  Yet she herself has lived all her life in a black and white room and has never seen colour.  When she is released from the room she learns something new – ‘what it is like’ to perceive colour.  Therefore this extra knowledge – the qualia of colour – cannot be physical facts.

 

Here is the Mary argument in the form of two premises and a conclusion:

 

Premise 1:  Mary has full knowledge of all the facts about the physical world, including full knowledge of the workings of her own brain.

 

Premise 2:  When Mary experiences the colour red for the first time she learns a new fact.

 

Conclusion:  The experience of the colour red is not a physical fact.

 

A fully explanatory account can be given of what happens to Mary assuming identity between qualia and neural processes in Mary’s brain.  This in itself does not do the work of refuting the Mary argument because it assumes that which the Mary argument claims to show is impossible (identity between qualia and physical brain processes).  However it is useful as a guide to point towards possible flaws in the Mary argument.  Under this identity account we see that Mary indeed has a new experience when she sees the colour red for the first time but that this is entirely compatible with a purely physicalist account of Mary’s mind. (I use the term physicalism instead of materialism but materialism can be exchanged with it).

 

Here is an account of what happens to Mary using the identity theory of mind:

 

IDENTITY ACCOUNT

 

Mary’s brain holds conceptual knowledge of ‘facts’ via particular type/s of specific neural interactions that are probably distributed through different areas of the brain but may be more or less localised in an area of the brain.  Whether or not they are localised the neural interactions are of a specific type or types involved in concept formation and storage.     

Other type /s of neural interactions are concerned with registering and interpreting visual sensory information, in particular the colour red.  Probably different nerve fibres are involved altogether and there may be a different location in the brain for this activity (but if not the type and manner of interaction is different to the concept-forming activity.) 

 

Mary’s conceptual knowledge of ‘facts’ all involves activity in the conceptual knowledge complex of the brain.  This knowledge can include full details of the facts about nerve fibres and their interactions in her own brain (there may be an issue about the physical capacity of Mary’s brain to hold all these facts but for the sake of the argument assume that she can).  The conceptual knowledge can include the facts about all the neural events that happen in the visual information complex of the brain when appropriate nerve signals come in from the eyes.  Mary also knows all the facts about how objects reflect different wavelengths of light and that these result in different neural events in the visual reception area of the brain.  She also knows that these different wavelengths of light are ascribed their various colour names.  She is able to predict exactly the physical events and changes that will occur to the appropriate neurons in the future if light of a particular frequency (red) should stimulate her retina.  Mary knows all this via activity in the conceptual knowledge complex of her brain. 

 

However the actual neural activity that results when red light strikes the eyes causing nerve signals to travel to the visual information area of the brain does not occur until those nerve signals actually do come in from the eyes.  Until then the nerve fibres concerned do not fire (or at least the appropriate pattern of firing does not occur).  Until they do fire Mary does not have the qualia experience of the colour red.  Now when they do fire Mary has a new experience.  If the word Knowledge is taken to embrace both conceptual and experiential knowledge then Mary now gains new knowledge.  She gains knowledge both in terms of the direct experience itself (the qualia) and in terms of any extra concept she now forms as a result of the experience.  If the word Fact is taken to embrace experiential facts then Mary now learns a new experiential ‘fact’ (as well as any additional concepts formed about that fact).

 

Regardless of word usage, Mary certainly does learn “what it is like” to have an experience of the colour red when the appropriate nerves fire in the appropriate way.  Until they do so she cannot.  Of course, if Mary manages somehow to get those nerves to fire in the appropriate way without impulses coming in from the eyes, then yes, she would have the experience of the colour red in advance of seeing with her eyes.  Likewise perhaps she could simulate the appropriate type and pattern of firing in another part of the brain, using other nerves, and get an experience of the colour red that way via some sort of creative imagination. 

 

Yet all of the above takes place in a physical brain in which the experience of the colour red simply is the appropriate pattern of firing of the appropriate nerves.  The above description gives a full account of what happens to Mary in purely physical terms, assuming identity between brain processes and mental activity including the experience of qualia.

 

THE MARY ARGUMENT

 

Now I turn to the Mary argument itself.

 

Here is the Mary argument again in the form of 2 premises and a conclusion:

 

Premise 1:  Mary has full knowledge of all the facts about the physical world, including full knowledge of the workings of her own brain.

 

Premise 2:  When Mary experiences the colour red for the first time she learns a new fact.

 

Conclusion:  The experience of the colour red is not a physical fact.

 

Looking at premise 1 we see that it is fundamentally an epistemological statement.  It asserts that Mary has knowledge.  It asserts nothing directly about ontology.  Knowledge (as it is usually understood) about things is not the things in themselves.  Let’s take “facts about the physical world” as the things that exist (or events that actually occur).  The first premise asserts only that Mary has knowledge about those things.  Knowledge is not identical with the objects of knowledge.

 

Looking at premise 2 we see that this is also an epistemological statement.  It asserts that Mary experiences something and she learns something ie she gains new knowledge.  In the usual understanding of knowledge the new knowledge she has gained would be about a fact.  It would not be the fact in itself.  In this case, for the purposes of the Mary argument, we can understand “fact” as something (or events) that exist, whether physical or non-physical.  The Mary argument in total wants to demonstrate that the new fact is non-physical, but premise 2 itself is an epistemological statement referring to Mary’s knowledge about something.  It is not an ontological statement.

 

The conclusion is an ontological statement.  It asserts that the new knowledge Mary has gained is not itself a physical fact.  We have jumped from statements about epistemology to a statement about ontology.  But there is a distinction usually made between epistemology and ontology.  Knowledge about things is not the things in themselves.  If that is the case then we would think that we cannot draw conclusions about ontology from merely epistemological statements. 

 

However we also notice that for the first time in the argument the conclusion makes self-reference to what could be considered a type of knowledge; “experience”.  The ontology in the conclusion refers to the experience itself.  If experience is to be counted as a type of knowledge then we do not necessarily have the separation between knowledge and ontology that is usually assumed.  For example, I said in commenting on premise 2 above, that under this assumption the new knowledge Mary gained was about a new fact, it was not the fact in itself.  But if the sensory experience itself is to be included in the category knowledge then the “fact” she ‘learns’ can be considered to be the experiential knowledge itself. 

The whole point of the Mary argument is to comment on the ontology of experience (qualia) so if experience is to be included in the term knowledge we have to admit an ontology of knowledge.

 

Certainly in the Identity theory of mind ontology and knowledge fuse because knowledge, whether conceptual or experiential, simply is identical with physical neural processes.  And here in the Mary argument a qualia experience of the colour red is being included within the category ‘knowledge’, and it is also being called a ‘fact’ (although we don’t know whether it is a physical or non-physical fact).  If ‘fact’ is confined to the ontological category then here the Mary argument is saying that in this instance (concerning a qualia of the colour red, but presumably all sensory experience) knowledge is identical with ontology (however the Mary argument concludes it is non-physical ontology).

 

We need to know what is to be included in the category ‘knowledge’ and what is to be included in the category ‘facts’ in order to evaluate the argument.  What is included in these categories should remain consistent throughout the argument in order for the argument to work.

 

The Identity account I gave of what happens to Mary suggests that we should divide the term knowledge into ‘conceptual knowledge’ and ‘experiential knowledge’ (where in this case experiential knowledge is sensory experience).  Conceptual knowledge is the type of knowledge where there is a distance between the knowledge itself and the facts it relates to.  In Mary’s case she has conceptual knowledge of physical facts about the world including her own physical brain.  Later on she gains some experiential knowledge as well, and in this case the knowledge is itself the fact (whether physical or non-physical).

In addition Mary may now form new concepts about the experience.

 

In the case of experiential knowledge, items of knowledge become identical with items of ‘fact’.  Conceptual knowledge is separate from the facts it relates to and experiential knowledge is identical with the ‘facts’ concerned.

 

Likewise we have to distinguish 2 types of learning: conceptual learning and experiential learning.

 

We can now paraphrase the Mary argument this way:

 

Premise 1:  Mary has conceptual knowledge of (all) physical facts.

 

Premise 2:  Mary gains experiential knowledge of a new experiential fact.

 

Conclusion:  The experiential fact is not a physical fact.

 

In premise 1 Mary holds concepts which represent in some way physical facts.  These physical facts are not the concepts themselves – the concepts represent the facts.

 

In premise 2 Mary has a direct experience which is not a concept.  The direct experience is itself the experiential ‘fact’.  We must add the rider that as a result of this experience Mary could now form new concepts about the experience.  These new concepts would be representations about the new experiential ‘fact’.  They would not be the experiential fact itself.

 

Does the conclusion follow from the premises? 

 

The type of knowledge and type of fact has changed from Premise 1 to Premise 2.

The new experiential fact is known by experiential knowledge – a direct experience which is not the same way of knowing as knowing by concepts.  Therefore the new fact could be one of the physical facts from Premise 1 known in a new way. 

 

Premise 1 makes the claim that Mary’s (conceptual) knowledge covers the entirety of physical facts.  There are no physical facts left not covered by Mary’s knowledge.  In principle these could include knowledge of all past events and predictions of all future events, or at least knowledge of exactly what would happen physically in Mary’s brain if she should see something with the colour red.  However when these physical facts do actually happen Mary knows them in a new way – as a direct experience.  Thus the experiential fact (qualia of the colour red) could be those very physical facts.  The conclusion of the Mary argument does not follow from the premises.

 

One possible response could be to deny that knowledge can be divided into two types.  Perhaps there is only one type of knowledge.  If so, it would have to correspond with what we have been calling conceptual knowledge.  A property of conceptual knowledge is that it is not the things that it represents.  Premise 2 claims that Mary “learns a new fact”.  Perhaps this is the same as gaining conceptual knowledge of a new fact (and there is only one type of learning – conceptual learning).  We can still call the new fact an “experiential fact” (which has an unknown ontology) – this is simply the qualia – the “what it is like” to experience the colour red.  But assume that this is known conceptually.  If desired we can even drop the label conceptual and just use the term knowledge, since there is now only one type of knowledge.

 

The argument is now:

 

Premise 1:  Mary has (conceptual) knowledge of all physical facts.

 

Premise 2:  Mary gains (conceptual) knowledge of a new experiential fact.

 

Conclusion:  The experiential fact is not a physical fact.

 

As before premise 1 states that Mary knows the entirety of physical facts.  She can make predictions about future physical facts and knows exactly what will happen to her neurons when she sees the colour red.  Premise 1 appears to leave no room for any additional physical facts.

 

In premise 2 Mary gains knowledge of a new fact.  But there would appear to be no room for any additional physical facts, and the physical facts from premise 1 cannot now be known in a new way.  So it would appear the new experiential fact cannot be a physical fact.

 

However we have left out one vital ingredient – time.  What happens to Mary takes place over time, as is made explicit at the beginning of premise 2 (in its original form) with the word “when”.  We saw from the Identity account, that until the neurons concerned with colour vision fired Mary did not have a direct experience of the colour red.  This was regardless of the amount of concepts Mary held in the conceptualising part of her brain.  The event of the firing of those neurons does not take place until it takes place.  The experiential ‘fact’ that takes place does not occur until the event of the firing of those neurons.  Mary could in principle predict that it will take place but as we have already seen – conceptual knowledge about something is not the thing in itself – in this case it is not the actual event, it is a representation of that possible future event.

 

Using time and facts alone I can show that there is room for more physical facts when Mary experiences the colour red.  This is because physical facts include physical events.

 

When the experiential event takes place the store of facts (of whatever kind) in the world increases.  It increases with an experiential fact, an event.  The set of facts has increased.

Included in these new facts are physical facts, physical events in neurons.  Mary had predicted these would occur and now has additional knowledge – they have occurred. Even though Mary could predict that the event would occur, and therefore had a representation of that event as a concept, this was not the actual event.  When the event occurs the set of event facts has increased by one (or many if we consider all the events involved in colour perception).  Since the set of facts has increased there is room for that many more physical facts.  When Premise 1 says that Mary has knowledge of all physical facts it can only mean all physical facts as at the time concerned (plus predictions of future events).

 

Here is the Mary argument paraphrased with time included:

 

Premise 1:  At time T1 :  Mary has (conceptual) knowledge of all physical facts as at T1 (plus predictions of future events).

 

Premise 2:  At time T2 :  Mary has (conceptual) knowledge of a new event (the experiential event, qualia of the colour red).  The number of physical facts in the world has increased because there have been new firings of neurons.  These facts are not identical with Mary’s concepts of these new firings at time T1. (Mary’s concepts are about the events but are not the events themselves). 

 

The conclusion “experiential facts are not physical facts” (or in the original form “the experience of the colour red is not a physical fact”) is no longer tenable.  It is entirely possible that the new experience is new physical facts – ie the new neuronal events themselves.  It is also possible that it is not.  No definite conclusion can be drawn about the ontology of the new experience.

 

Combining both the idea of two types of knowledge and the time factor: there is a disconnection between conceptual knowledge of events and those events themselves.  On the other hand the experiential knowledge Mary gains in premise 2 is the event itself (plus Mary may form extra concepts resulting from the event).  Mary’s experiential (and possibly conceptual) knowledge has increased but so has the set of physical facts increased, in the form of new neuronal events, so it is quite possible that Mary’s new experience is those extra physical facts themselves.

 

I suggest a very reasonable hypothesis is that the new experience is identical with the new physical facts.

 

David Chalmers believes that the strategy a physicalist must take to the Mary argument is to deny that Mary gains any new knowledge about the world when she sees the colour red (Chalmers 1996).  He rejects the idea that knowing an old fact in a new way (eg through experiential knowledge rather than conceptual knowledge) is not learning a new fact:

 

“It follows that if Mary gains any factual knowledge that she previously lacked – even if it is only knowledge of an old fact under a different mode of presentation – then there must be some truly novel fact that she gains knowledge of.  In particular, she must come to know a new fact involving that mode of presentation.  Given that she already knew all the physical facts, it follows that materialism is false.  The physical facts are in no sense exhaustive.” (Chalmers 1996). 

 

In my argument I do not deny that Mary learns a new experiential fact plus any new conceptual facts that go along with it.  I accept that Mary gains new knowledge.  What I contest is that Mary’s conceptual knowledge of all the physical facts at a certain time T1 precludes the coming into being of new physical facts (physical events) at a later time T2.

Even if Mary has predicted these events at T1, when the events occur at T2 she gains new knowledge – of the occurrence of the events.  Hence the new novel facts she learns, including the qualia of the colour red, can be physical facts.  Mary’s knowledge of all the physical facts is exhaustive at the time she has the knowledge.  At a later time there can be new physical facts in the world.

 

Chalmers is wrong that a physicalist has to deny that Mary makes any new discovery about the world.  For the very reason that the world moves on and is continually accumulating new physical events Mary should be continually discovering new facts.

 

 

JANET’S REASONABLE HYPOTHESIS

 

The Mary argument is one form of the Knowledge argument.  All the forms purport to show the impossibility of a physical identity for qualia, the “what it is like” of conscious experience.  The Knowledge argument uses knowledge of the physical facts of brain processes to exclude the experience of qualia from the physical fold.  Regardless of the validity of the argument itself, it can carry intuitive force.  As Frank Jackson, the originator of the Mary argument, says in the article in which he first proposed the argument “…the polemical strength of the Knowledge argument is that it is so hard to deny the central claim that one can have all the physical information without having all the information there is to have.” (Jackson 1982).  The extra information there is to have is the experience of qualia. 

 

Jackson’s statement is a little misleading.  As I argued above, it is not a matter of just having information in the form of conceptual knowledge, qualia experience is a different kind of ‘direct’ information (or, equivalently, a different way of knowing information)  and it is not possible to have all the information until the event/s of qualia occur.  However there is certainly a strong intuition that qualia cannot be identified with physical events.  I think the source of that intuition is a disconnect between 2 mental pictures, usually visual.  On the one hand we introspect and experience what seeing the colour red is like.  On the other we have a visual mental picture of a tangle of neurons in our brains and wonder how any activity of that could possibly be identical with the beauty and subtlety of our experience of the red in the sunset.  Of course, we don’t only have to imagine the neurons, we can actually look at pictures of them or see the real things through a microscope and measure their activity.  They don’t look anything like our experience of the colour red.

 

In this section I investigate the source of our intuitive mistake.  The basic error is in comparing qualia from 2 different objects and expecting them to look the same if the Identity hypothesis is correct.  But they shouldn’t look the same because the qualia are caused by different objects.  Instead what happens according to the Identity hypothesis is that the qualia caused by one object are identical with activity in a second object and this activity in the second object is in turn the object for a second set of qualia.

 

Here is a thought experiment which simply extrapolates into the future the capabilities of neuroscience.  We start our investigation with qualia itself:

 

Janet is a scientist who experiences qualia of the colour red from a red object in her laboratory.  Call this qualia Q1.  Call the red object RO.  She has already hypothesised, from her experience, that the qualia of red she experiences is caused by the presence of the red object in her laboratory.  She hypothesises this from the correlations between the presence of the red object in front of her eyes and her experience of the colour red.  This is simply the inference we all build up from when we are babies: that there is an external world causing our experiences.  Everyone regards this as a reasonable hypothesis under the circumstances.

 

Now Janet wants to investigate what is happening in her brain when she sees the red object.  Fortunately technology has advanced to the level where there is a device which can peer into Janet’s brain and display, visually in real time, the electrical activity in the neurons concerned with visual processing.  Janet discovers that every time she experiences qualia of the colour red there is particular activity in particular neurons in her brain, and this occurs concurrently with her experience of the colour red.  She has to look at a screen to see the activity of these neurons (which let us say displays a picture of the neurons as well as showing their activity and giving a time display), or alternatively imagine that she can see the neurons by direct light as under a microscope.  Of course there is a problem with experiencing the colour red and at the same time observing the neurons, but imagine that this can be overcome by a measured time delay on the screen from the recording device, so that Janet knows there is a correlation between her experience of the colour red and the neuronal activity. 

 

Call the qualia Janet has from observing the activity of her neurons Q2.  This is a different experience from Q1 (which comes from the red object).  Janet hypothesises that Q2 is caused by activity in the neurons, just as Q1 is caused by the red object.  Call the activity in the neurons NA.  Now Janet makes a further reasonable hypothesis: that Q1 is identical with the activity in the neurons: Q1 = NA.  Note that Q1 is not identical with Q2, they are different qualia caused by different objects.

 

Why is Janet’s hypothesis reasonable?  Because the red object (RO) causes Q1.  And particular neural activity (NA) causes Q2.  But Q2 is correlated with Q1.  So the particular neural activity NA is correlated with Q1.  Hence the hypothesis that Q1 is the particular neural activity.

 

It is not the only hypothesis that could be made.  Others are

1. The red object causes both neural activity and Q1 separately    (RO causes NA and Q1)

2. The red object causes neural activity which causes Q1         (RO causes NA causes Q1)

3. The red object causes Q1 which causes neural activity    (RO causes Q1 causes NA)

However Ockham’s Razor may reasonably be used to cut out the extra lengths in the causal chain to produce the simpler Identity hypothesis.

 

Hypothesis 2 could correspond with epiphenomenalism if rephrased as ‘the red object causes neural activity which is accompanied by Q1’ to avoid the word ‘cause’ for the second relationship.  Likewise Ockham’s Razor may reasonably be used to reduce the 2 entities of epiphenomenalism, Q1 and NA, to one.  This single entity could now be described in two ways, as Q1 or NA, because Q1=NA.

 

Janet’s reasoning can be summarised as:

Q1 is caused by RO

Q2 is caused by NA

Q1 is correlated with Q2

Therefore NA is correlated with Q1 (and RO)

Reasonable hypothesis:  NA = Q1

 

We do not expect that our observations of the neural activity should look like the qualia of the colour red.  The qualia of the colour red is caused by a red object in the laboratory, whereas the qualia of the screen display of neural activity is caused by the nerves in Janet’s brain. 

 

Qualia are not identical with the objects of perception (they are caused by them).  They are not even good representations of the objects of perception.  Unfortunately we think that our sensory qualia are accurate ‘pictures’ of what is really out there.  They are not.  They are imperfect representations caused by objects in our environment.  They are accurate to only a very limited extent but do not reproduce the true nature of objects.  For example the qualia of the colour red is caused by light of a particular frequency range from an object.  The red colour we experience is only a representation of that frequency range and tells us nothing directly about the wave nature of light or its electromagnetic nature.  We cannot discern the atoms that compose the red object either.  But we do know that the experience of the colour red is associated with whether we are seeing that particular object, so we can say it is caused by the presence of that object in front of our eyes. 

 

Likewise the qualia we have when we look at nerves (or as we imagine Janet is able to do – the activity in the nerves) is not the objects themselves or the activity itself.  It is a representation caused by that activity, and a very imperfect representation of what is actually going on at the molecular or atomic level in those structures.  What we have with qualia is a causal story.  We should not expect that we automatically know the true nature of the objects of our perception, through perception itself.  

 

Now if we turn our attention to the qualia experience itself should we expect that we know its true nature?  If qualia are at bottom representations caused by objects stimulating our senses, then how are we to discern the true nature of those representations?  We would need further qualia caused by those qualia, to peer into the nature of the first.  These further qualia would also be representations – representations of the representations making up the first qualia.  We should not expect that we automatically know the true nature of our representations just from the experience of the first qualia. 

 

But the former situation is exactly Janet’s experiment.  She used qualia of nerve activity to peer into the nature of her qualia of the colour red.  She observed a correlation.  This did not give her a direct perception of the nature of her qualia of the colour red.  This gave her a representation of the elements and structure (actually events) of her representation of the colour red.  The one is not more real than the other.  They are both different representations of an underlying reality.  But they enable Janet to make a causal correlation between Q1 and Q2.  Not posit identity between Q1 and Q2, far from it – they are different representations and under the Identity theory of mind they are identical with very different neural events.  Instead Janet hypothesises identity between the object of Q2 and Q1 itself, identity between whatever is being imperfectly represented by Q2 and Q1 itself.

 

We cannot expect that we, as representing machines, be able to directly discern the elements of our own representations.  Instead we need further representations to represent our representations.  This does enable us to make correlations however.  And from those correlations we can make the very reasonable hypothesis that our experiences, our representations, are identical with what we observe when we observe particular brain processes.  This was Janet’s reasonable hypothesis. 

 

REFERENCES

 

Chalmers D. J.  ‘The Conscious Mind’  (1996)  New York, Oxford  Oxford University Press  p145 & p144

 

Ibid  p142

 

Jackson, F. ‘Epiphenomenal Qualia’ in Philosophical Quarterly. V 32 (1982) pp.127-36

 

Ibid  p130

 

 

CV:   Colin Mitchell is a BA graduate in English Literature who has studied Philosophy and Physics at AdelaideUniversity, FlindersUniversity and Melbourne University, Australia.

 

 

Contact:  colinmitchell9@yahoo.com.au