Motivated by Darwin’s theory of evolution, we think consciousness must have a function. We think consciousness must play some role in our behaviour, and be able to cause and influence what we do. We think about raising our left arm, and then it raises. Surely consciousness has causal power. But this is an illusion, writes Helen Yetter-Chappell.

For more on Darwin vs Consciousness, the world’s largest philosophy and music festival, HowTheLightGetsIn, will be hosting a debate this May. Featuring Denis Noble, Stuart Hameroff, Antonella Tramacere and Güneş Taylor debating whether consciousness and the theory of evolution are incompatible.

You go up to a food truck and order a falafel wrap. Why? Because you felt hungry. You grab a hot pan on the stove, and you pull your hand back, yelping. Why? Because touching the pan hurt. Our world is filled not just with physical objects around us, but with conscious experiences. And our conscious experiences guide us in our interactions with the world. Nothing could be more obvious.

… Or so the standard picture goes. I think this picture is wrong. I agree that there are physical objects. And I agree that there are conscious sensations of hunger and pain. What I disagree with is the idea that conscious sensations guide us – or influence our behavior in any way – as we interact with the physical world. If I’m right, there is no causal interaction between our conscious experiences and the physical world. This is a position philosophers call epiphenomenalism. It may sound crazy at first, but it’s well-motivated once you appreciate the arguments for it.

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The epiphenomenalist concludes that consciousness doesn’t explain our behavior.

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Mental States Aren’t Causal

Why would one be an epiphenomenalist? The basic motivation comes from embracing two claims:

1. Physical things can be completely explained by physical things.

2. Consciousness isn’t physical: it’s something more.

To see why epiphenomenalism is a natural consequence of these theses, it can help to use pictures. (The dotted arrows show causation.)

1. Physical things can be completely explained by physical things.

There’s a complete physical explanation of why lightning causes thunder, why heliotropic plants track the sun, why pressing the brake pedal of your car causes it to stop … and why stubbing your toe causes you to hop around wailing.

Our bodies/brains are just one more physical thing among many. To explain their behavior – grimacing, wailing, or more complex vocalizations like saying “ouch” – we need look no further than the physical world.

2. Consciousness isn’t physical: it’s something more.

Physical explanations give brilliant accounts of the functioning of physical systems. But the sensation of pain (longing, vertigo, delight) has a subjective first-person feel. It’s mysterious why and how one could get feel from function or first-person perspective from third-person behavior.

Dualists argue that we can’t “get feel from function”. No matter how many Lego pieces you put together, no matter how complex the arrangement, the Legos will never become the feeling of pain. At best, the Legos may – like our brains – generate or “give rise to” a new thing, which is the feeling of pain.

The point here is a subtle one. Dualists don’t deny that our experiences correlate with the functioning of physical brain states. But there are different ways to explain correlations. Sometimes when two things are correlated, it’s a statistical fluke, and there’s no real relation between the things. Sometimes, it’s because there aren’t really two things – just two ways of describing one thing. (For instance, H2O and water go together. This correlation isn’t random, nor is it because H2O causes water to appear. Rather H2O just is water.) Other times, the relation is one of causation. When you come down with the flu, you suffer from a variety of unpleasant symptoms. These symptoms aren’t identical to the virus; rather, they are caused by the virus. Likewise, as the dualist sees it, the functioning of your physical brain isn’t identical to experiences; rather, your brain’s functioning causes us to have experiences.

Let’s put (1) and (2) together.

(1)                                           +                          (2)                            = (3)

3. Consciousness doesn’t explain our behavior.

It follows that we can completely explain our behavior in terms of physical things – without making reference to consciousness. So consciousness isn’t necessary to explain our behavior after all!

The epiphenomenalist concludes that consciousness doesn’t explain our behavior. Everything our physical bodies do – from movements of our bodies to the vibrations of our vocal cords – is explained by other things our physical bodies do. Our experiences… they’re something extra, along for the ride.

Notice that there’s no downward arrow from the hurty feeling to the body hopping and wailing. The hurty feeling didn’t cause the person to hop or wail… the physical happenings within their body did. The hurty feeling is an epiphenomenon.

There’s far more that needs to be said to thoroughly defend each of these theses. Dualism, the view that consciousness is a non-physical addition to our physical world, is particularly controversial. But even among philosophers who accept dualism, few embrace epiphenomenalism. The reason is that epiphenomenalism is widely taken to have preposterous consequences.

I think this is a mistake.

Objections to Epiphenomenalism

Objection 1: Denying the obvious

Most people reject epiphenomenalism without serious consideration. Why? It just seems obvious that our experiences affect our actions. Desires can feel like a pull tugging you towards the object of your desire. Pain feels aversive. So denying that this conscious feel affects you seems to be denying the obvious.

While this isn’t an argument, it carries serious weight. I may not have an argument that one line is longer than another. But I don’t need one. Its truth is manifest just by looking at the lines. Any time a view that denies what seems obvious, it has some explaining to do.

That said, what seems obvious may not always be true. Two identical twins in the Ames room seem different sizes – but they’re not. The lines in the Muller-Lyer illusion seem different lengths – again, they’re not.

When confronted with two people who seem to be different sizes, our first assumption should be that they really are different sizes. But this is defeasible. If we learn that they’re in an Ames room, or discover that we’ve been given a drug that makes us terrible at judging size relations, we should no longer put such faith in the “obvious”.

Epiphenomenalists think this is just the sort of situation we’re in when it comes to the causal efficacy of experience. We think we’re experts at detecting causation. But really, we’re more like the person who’s been drugged with a size comparison distortion drug.

Suppose you’re watching a tennis match. You see Serena Williams hit the ball. Ball and racket collide, causing the ball to hurtle over the net.  It seems to you that there’s causation at work. And you’re right.

But now suppose you’re watching the match on a big screen. You may not even realize it’s a screen. Perhaps you’re outside, and the screen is perfectly positioned in front of you to give the illusion of being a live match. From your perspective everything is precisely the same as before: ball and racket seem to collide, causing the ball to hurtle over the net. But there’s no causation at work in what you’re seeing. There’s no ball colliding with a racket inside the screen. There’s no transfer of force. What there is is pixels changing color, one after another, to give the illusion of motion; the illusion of causation. This is true whether the images on the screen reflect a real game of tennis, or computer generated graphics with no causation in the background at all.

We are spectacularly bad at detecting causation. When fans in a stadium do the wave, it looks to us like there’s something moving across the stadium. (There isn’t.) Sequential light displays look like they involve motion. (They don’t.) The tennis racket on the television looks like it causes the ball to move. (It doesn’t.) What’s going on? Why do we misidentify motion and causation in all these cases?

The trouble is that we don’t directly detect causation at all. What we detect is two events occurring in rapid succession. From this, we infer that there is causation. This often produces judgments that are correct. But it can also lead us astray. When parents first notice symptoms of autism in children shortly after the children are vaccinated, it can seem that the vaccine caused the autism. It’s understandable that some parents feel this way: this is precisely how we’re wired to detect causation. But in this case, the seeming leads us astray.

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We know about them in a far more intimate way than mere causation. We know our experiences because they are us.

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Epiphenomenalists contend that precisely the same thing is happening when it seems to us that our experiences cause our behavior. We desire chocolate cake – we reach for it. We feel sad – we cry. We feel pain – we pull our hand back. Two events – an experience and a physical action – occurring in rapid succession: We naturally view the former as causing the latter. But this doesn’t mean that it is.

Of course, this isn’t an argument for epiphenomenalism. That’s given by the argument at this start of the article. The point is just that the epiphenomenalist has good grounds for denying what initially seemed obvious.

Objection 2: The Impossibility of Thinking About Epiphenomenal Experiences

One of the most serious challenges facing epiphenomenalism is the “Paradox of Phenomenal Judgment”, discussed by David Chalmers in The Conscious Mind (1996). Here’s the basic idea:

1. Epiphenomenalists think there could be a creature physically just like you, but who doesn’t have conscious experiences. When they stub their toe, and cry “Ouch! That hurts!” the very same things are going on inside their brain; the very same things cause these sounds to leave their mouth.

2. So your non-conscious twin has the same beliefs as you, formed in the same way as your beliefs.

3. But your non-conscious twin doesn’t know anything about pain! They’ve never felt it!

4. If you have the same beliefs as your non-conscious twin and you formed your beliefs in the same way, there’s nothing that distinguishes your belief from theirs: So you also don’t know anything about pain.

5. So epiphenomenalism entails that we don’t know about our pains.

The reasoning generalizes. If this argument is sound, epiphenomenalism commits us to the idea that we don’t know anything about consciousness at all! And since the whole motivation for embracing epiphenomenalism started with a claim about consciousness, this would undercut the whole basis for embracing the view!

I’ve argued elsewhere that this so-called paradox comes from failing to fully appreciate epiphenomenalist dualism as a form of dualism. In imagining that my non-conscious twin has the same beliefs as me, premise (2) implicitly presumes that beliefs and subjects are physical things. (Physical stuff is all that I share with my non-conscious twin, so to have the same beliefs, beliefs must be physical.) But as the dualist sees it, conscious experiences are essential to me and to my beliefs. I’m not a physical entity with consciousness tacked on as an extra. I am the conscious entity.

Many of the things we know about are known because they causally affect us. I know there’s a cup of tea sitting on my desk because of the causal chain connecting the tea to my retina and ultimately to my brain. For the epiphenomenalist, our conscious experiences don’t causally affect us. But that doesn’t mean we can’t know about them. We know about them in a far more intimate way than mere causation. We know our experiences because they are us. Our loves, our longings, our rage, our pain: they are who we are. I am not a lump of physical matter. I am the conscious being who this physical matter creates. My beliefs are conscious beliefs. They are not beliefs held by a physical brain, but by a conscious subject.

My non-conscious twin may be physically identical to me. She may have the same things happening in her brain as those that generate my conscious feelings and beliefs. But she is not a subject, and she no more shares my beliefs than she shares my pains.

While this “paradox” looks puzzling on its face, it simply arises from a mis-match of theories. It should be no surprise that combining dualism about experiences with physicalism about subjects and beliefs has bizarre effects. But these bizarre effects are no more a challenge to the dualist (epiphenomenalist or otherwise) than they are to the physicalist (whose views of subjects and beliefs are incompatible with dualistic views of experiences).

  SUGGESTED READING Consciousness does not require a self By James Cooke

Objection 3: Epiphenomenalism Makes Consciousness Irrelevant

People sometimes claim that epiphenomenalism means that consciousness is irrelevant. But that’s not the view. Nothing could be more relevant to me, to my identity, to my well-being than consciousness. Conscious experiences explain what I feel; they explain who I am; they give value to my existence. Epiphenomenalism simply holds that consciousness doesn’t explain the movement of my limbs and the vibration of my vocal cords. Consciousness matters … just not to physical events.

But the reason to posit that we’re conscious isn’t that it’s the only way to explain why our limbs move. It’s that we feel things, and we know we feel things. We love, we hate, we suffer, we experience the smell of dried leaves and the crunching underfoot. Epiphenomenalist dualism is all about capturing that … without giving up on science.