Friday, 19 February 2016

Frank Jackson’s ‘Epiphenomenal Qualia’ (1982)

i) Introduction
ii) The Modal Argument Against Physicalism
iii) What is it like...?
iv) The Bogey of Epiphenomenalism

Firstly, Frank Jackson introduces us to Fred. Fred can see two colours in a given area; whereas we can see only one. The problem is that he's unsuccessful when it comes to teaching the rest of us the difference between red-1 and red-2. We can't make that distinction. Fred, therefore, concludes that “the rest of the world is red-1/red-2 colour-blind”. The point is that Fred has a different phenomenal experience to the rest of us. He has the “ability” to distinguish two shades of red which we can't distinguish.

Jackson concludes that it won't help us to understand the difference between red-1 and red-2 even if we were to know everything there is to know, physically, about both red-1 and red-2. There must therefore be a phenomenal gap between the physical and either red-1 or red-2 (perhaps both). Either one or both must run free (as it were) of any physical underpinning.

Despite all that, researchers do find a physical explanation as to why Fred can distinguish between red-1 and red-2. In this hypothetical situation we

find out that Fred’s cones respond differentially to certain light waves in the red section of the spectrum that make no difference to ours (or perhaps he has an extra cone) and that this leads in Fred to a wider range of those brain states responsible for visual discriminatory behaviour”.

Yes, you guessed it, this imaginary state of physical affairs doesn't have the slightest impact on Jackson’s argument. It's indeed the case that red-2 has its own physical underpinning. It's also the case that we have full physical knowledge as to why Fred can distinguish between red-1 and red-2; though we still can't distinguish red-1 from red-2. We still can't read-off the extra colour from the new physical information we've acquired of Fred’s brain, eyes, etc. And nor can we infer or deduce what red-2 is like from these physical facts. There's still a gap between our knowledge of the physical and our knowledge (or lack of knowledge) of the phenomenal (i.e., if we can call phenomenal knowledge, knowledge at all).

The Modal Argument Against Physicalism

Jackson then brings on board a modal argument; as well as giving attention to the possibility of zombies. In fact the zombie possibility starts off with a logical argument - or at least with a statement about the limits of logical entailment.

Mary may well have all the physical information about red (or about red’s physical underpinnings). Similarly, we may have all the physical information about what seems to be another person. Jackson argues that

no amount of physical information about another logically entails that he or she is conscious or feels anything at all”.

This is an incredible conclusion. It's not only about the possibility of zombies: it also applies to all our fellow human beings. Perhaps it's a new take on the “problem of other minds” in that Jackson argues that a complete physical picture won't tell us whether or not another being is conscious or feels anything at all. As with other-minds arguments, we inductively infer that other people have minds and feel pain because of their behaviour and what they say (although verbal expressions are a form of behaviour). Though, again, we can't say that behaviour alone logically entails consciousness or pain. However, we have good reasons to believe that other people do suffer pain, etc. (though that’s another story). In the case of zombies, we can say that a zombie is physically and behaviourally identical to us, yet he won't be conscious and he won't feel pain. More technically, he may have the same “functional states” too. Jackson concludes by asking us a very telling and simple question:

But then what is it that we have and they lack?”

Of course he answers his own question thus:

Not anything physical…”

Jackson's self-questioning concludes with the statement that “[c]onsequently there is more to us than the purely physical”. Thus: “Thus Physicalism is false.”

As it stands, this seems to assume that the phenomenal - by definition - must be nonphysical. Many philosophers reject this. Indeed, according to certain physicalists (such as David Lewis), they do think that the phenomenal is something over and above the physical – or, at the least, above the physical as we currently describe it. (The point, however, is that we can't have new knowledge of an experience of red, etc.) Jackson tells us that certain philosophers

sincerely deny that there cannot be physical replicas of us in other possible worlds which nevertheless lack consciousness”.

Perhaps we can say here that such beings couldn't exist according to the physical laws of our world. Aren’t philosophers usually talking to us about the possibility of zombies in our world? Or, at the least, about zombies at a possible world which still nevertheless shares our laws of nature? However, isn’t it logically possible that zombies could exist not only at other possible worlds; but also in our own? Isn't this scenario metaphysically possible?

What is it like to be...?

Thomas Nagel offered us something very special to this general debate when he published his paper, ‘What is it like to be a Bat?’. Very generally, S can't tell us what it is like “from a bat’s point of view”. The bat’s point of view is “not our point of view”. In addition, the bat’s point of view

is not something captureable in physical terms which are essentially terms understandable equally from many points of view”.

David Hume (according to Jackson) offered an argument that goes against the general position (at this time). Hume argued that

from knowledge of some shades of blue we can work out what it would be like to see other shades of blue”.

So did Hume believe that we could deduce (or infer) what a new shade of blue is like simply by studying the physical basis of the given shades of blue? Or did Hume mean that we could work out a new shade of blue from the shades of blue we've already seen (i.e., not from the physical substructure of our known shades of blue)? These two claims are quite different.

For example, we could work out the physical substructure of another shade of blue by examining it. Though we still couldn't imagine another shade of blue. As for inferring another shade of blue simply from our previous experiences of known shades of blue: this is equally contestable and probably untrue. Indeed both hypotheses seem untrue, at least prima facie.

The Bogey of Epiphenomenalism

Jackson now introduces epiphenomenalism into the debate.

What is epiphenomenalism?

Well, for a start, epiphenomenalists don't deny qualia. However, they do

countenance the idea that qualia are causally impotent with respect to the physical world”.

Again, believers in epiphenomenalism don't necessarily deny that there are qualia. Instead they believe (or some of them do) that it's “possible to hold that certain properties of certain mental states” can indeed be seen as qualia. However, “their possession or absence makes no difference to the physical world”. They are "causally impotent".

Perhaps, however, an epiphenomenalist can accept that the

instantiation of qualia makes a difference to other mental states though not to anything physical”.

One can immediately ask here whether or not it's coherent to deny qualia causal efficacy at the same time as allowing that they may well make a difference to other mental states (regardless of their effect on anything purely physical).

There are good reasons for holding that qualia are indeed causally inefficacious.

For example, “a quale like the hurtfulness of pain must be causally efficacious in the physical world”. A pain is a phenomenal process that can cause us, for example, to remove our hand from a fire. This is a causal relation (or link) between phenomenal pain and the physical movement of a hand. Surely this causal link is real. However, there's a Humean argument against believing this which makes use of a general position which is taken from Hume’s well-known stance on causality. Jackson writes:

"No matter how often B follows A, and no matter how initially obvious the causality of the connection seems, the hypothesis that A causes B can be overturned by an overarching theory which shows the two as distinct effects of a common underlying causal process.”

We can rewrite the passage above by making it germane to our current debate. Thus:

No matter how often the removing of one’s hands follows one's experience of intense heat, and no matter how initially obvious the causality of that connection seems, the hypothesis that the intense heat causes the removal of one's hand can be overturned by an overarching theory which shows the two as distinct effects of a common underlying causal process.

In that case, what would that common underlying causal process actually be? Why augment entities at all by positing yet another causal process to account for the feeling of heat and the removal of the hand? The epiphenomenalist argument would of course be that instead of the feeling of intense heat being itself a cause of the moving of the hand, there will be a causal process which subserves the feeling of intense heat. It would be that underlying cause that prompts the sudden movement of the hand. The feeling of pain (or the quale) simply “rides on the top” of this so far undiscovered underlying causal process.

So why the quale or the feeling at all? What point does it serve? Why not simply do without it? Why not give a fully physical and behaviourist account of what happens? And if there is such an account, then what point is pain from an evolutionary point of view? Jackson alights on this last point. He asks:

We may assume that qualia evolved over time… and so we should expect qualia to be conducive to survival. The objection is that they could hardly help us to survive if they do nothing to the physical world.”

The assumption here is that everything about the human body and mind has its evolutionary value in the precise sense that it helps us survive in some shape or form. This is wrong... according to Darwinians.

Take the well-known case of a coat being both warm and heavy, which Jackson cites. A warm coat was clearly once conducive to survival for all kinds of animal (including human beings). The problem is that warm coats are also heavy coats. The coat’s heaviness was not conducive to survival (for obvious reasons). However, this example of both pro and con is adequately explained by evolutionists and indeed by Jackson. He writes:

Having a heavy coat is an unavoidable concomitant of having a warm coat… and the advantages for survival of having a warm coat outweighed the disadvantages of having a heavy one.”

What has this to do with the qualia debate? The epiphenomenalist argues that qualia

are a by-product of certain brain processes that are highly conducive to survival”.

As is often the case in many debates in the philosophy of mind, the problem of other minds also raises its head. In terms of qualia, we can ask the following question:

[H]ow can a person’s behaviour provide any reason for believing he has qualia like mine, or indeed any qualia at all, unless this behaviour can be regarded as the outcome of the qualia?”

Clearly another person’s physical behaviour doesn't point directly - or even indirectly - to the existence of qualia (like or unlike our own). So what's the point of qualia? Even if that question was answered a moment ago, can’t we still see this lack of behavioural evidence for qualia - as well as their very existence - as pointing us to the conclusion that behaviour must indeed be the outcome of qualia? Clearly an epiphenomenalist can't accept this conclusion.

Jackson then reiterates the basic epiphenomenalist position on qualia. He writes:

Now the epiphenomenalist allows that qualia are effects of what goes on in the brain. Qualia cause nothing physical but are caused by something physical.”

We know this position by now. However, the epiphenomenalist can still give a physical or behaviourist account of qualia. He does so in the following way:

Hence the epiphenomenalist can argue from the behaviour of others to the qualia of others by arguing from the behaviour of others back to its causes in the brains of others and out again to their qualia.”

The epiphenomenalist has already accepted qualia and he gives a physical account of them. Thus if the epiphenomenalist accepts that he indeed has qualia, he must make sense of this in terms of the behaviour of other people. If other people behave like him, and he admits to his own qualia, then he can happily accept that because others behave like him, then they (probably?) also have their own qualia. And because he's already argued that qualia are caused by the brain, then the brains of other people must cause their qualia too. Thus qualia are given a physical or behaviourist explanation, even if qualia are still seen as being inefficacious physically.

Many, if not all, epiphenomenalists argue that the supposed causal impotence of qualia is a godsend for die-hard (neo) dualists. They merely “sooth” their “intuitions”. The fact remains, however, that they are an "excrescence":

They do nothing, they explain nothing…”

At least they do nothing and explain nothing if one accepts the general epiphenomenalist position; which many philosophers of mind don't!

We talked earlier about the relevance of evolutionary theory on the qualia debate.

So what about an evolutionary account of our knowledge - or lack thereof - in regards to the reality of qualia? Perhaps our lack of knowledge of qualia can also be explained in evolutionary terms. Jackson states that

it is very likely that there is a part of the whole scheme of things, maybe a big part, which no amount of evolution will ever bring us near to knowledge about or understanding of”.

The simple reason for this is that “such knowledge and understanding is irrelevant to survival”. This may account for this epistemological dearth on our part. Similarly, it's been argued (by, for example, Donald Davidson) that certain false beliefs are quite helpful for survival in certain contexts! In addition, Jackson’s position is a little like Colin McGinn’s in that he talks in terms of “cognitive closure”. That is, we are (or we may be) cognitively incapable of acquiring a complete knowledge of consciousness (or of qualia).

Perhaps McGinn’s own position can also be given an evolutionary explanation.


Jackson, Frank. (1982) 'Epiphenomenal Qualia'.

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