So in Chapter 2 we left off asking a couple of questions:

How do we know when the pain conversation will start? And, how can we bring it to a close?

In this chapter we’re going to try to address these questions by defining why we get pain in the first place. So let’s see if we can define this “Pain Conversation” more clearly by using a quote from our new pain science friend, Professor Lorimer Moseley. It goes like this:

“Pain occurs when the brain concludes there is more credible evidence of danger related to the body than credible evidence of safety related to the body.” Explain Pain, 2003. Moseley and Butler.

Professor Moseley says he and his colleague, Dr David Butler, poured over this quote for weeks, removing every word that wasn’t important, and ensuring that what remained could explain exactly why pain occurs.

So let’s break it down for you here so you see it as clearly as they do.

“Pain occurs when the brain concludes there is more credible evidence of danger related to the body than credible evidence of safety related to the body.”

This first part is super important to understand, because it does not say, “Pain occurs when the BODY PART is damaged.“

ALL pain is in the brain, whether a body part is damaged or not.

This doesn’t mean you’re making it all up –– this isn’t the conscious, thinking, part of the brain projecting sensations. It’s the Cave Person inside that’s making conclusions about your body and telling you where on the body it wants you to focus your attention, by drawing your attention there.

Once this Cave Person part of you has made a conclusion about a body part, it starts a conversation through the language of Pain Sensation. And that brings us to a question: What is it concluding? Well, that…

“Pain occurs when the brain concludes there is more credible evidence of danger related to the body than credible evidence of safety related to the body.”

This second half is incredibly important to understand. It’s saying that this Cave Person inside you is responsible for monitoring the body’s safety, and if for any reason it concludes the body is in danger, then it’ll start a pain conversation with you. Simple as that.

And what’s mad is this –– If it believes a rubber hand is now part of your body then it’ll start a conversation about that rubber hand too –– and it’ll hurt just as much!

Check out this fun video demonstrating the Rubber Hand Experiment…

Wild, isn’t it?! This experiment shows how pain is entirely constructed in the brain and not in the tissues of the body. And this is because of two words in Lorimer Moseley’s pain statement above; and they are important enough to be repeated twice…

“Pain occurs when the brain concludes there is more credible evidence of danger related to the body than credible evidence of safety related to the body.”

Credible Evidence –– Now evidence is a tricky idea. There are all sorts of ways to collect evidence; not all of which are valid. We’ve just seen how invalid evidence can trick us into believing a rubber hand is in danger.

To understand how evidence can affect us, let’s take a look at our three injuries from the last chapter and run through the evidence the brain was concluding, starting with the stubbed toe.

Pain Conversation From A Stubbed Toe

In a stubbed toe your brain received evidence in the following ways:

• You gained “Sensory” evidence as the receptors in the toe were triggered at the moment of impact.
• There was “Witness” evidence as you were very aware of what happened at the time of impact.
• There was “Visual” evidence because you walked too close to the coffee table.
• There was “Auditory” evidence when you heard a bang or even a crack sound on impact.
• You received “Knowledge” evidence –– you know that the crack sound could mean you broke the toe (or the coffee table!)
• You received “Historical” evidence –– in the past stubbing your toe has made it sore.
• And you received “Imagined” evidence as you began to projected yourself into the future, worrying about whether you’d be able to pick the kids up from school later, or what the medical costs might be, or if you can still play sports this coming weekend, or whether you’ll need time off work etc.

So the weight of evidence is large, and the evidence all lines up. There is no evidence of any safety (yet!), only danger to your body.

Your brain collates all this evidence and concludes danger to the body, then instantly starts the conversation.

It starts with intense words––what you call ‘sensations’––like sharp and stabbing. It then moves a few minutes later to stiffness and throbbing, limiting your range of movement to a few degrees, and gives a sharp stab if you move it past this range. Then hopefully over the coming minutes, hours or days your joint mobility increases again and eventually the dull ache drifts away too.

This slow increase in allowable movement and a drift away of the dull ache happens as the brain becomes more and more confident that you didn’t do any lasting damage.

If you didn’t damage anything then this conversation is over within a few minutes or hours. But if you did sprain a joint or fracture a toe, then this conversation may last a few days to a few weeks.

In this scenario all the evidence stacks up nicely in the way we expect pain to occur –– we witnessed ourselves damage the body and the body part now hurts –– Nothing seems odd (yet!). But things start to get a bit weird in the next scenario.

The Cut Arm Whilst Gardening Conversation.

Now this is a different conversation because, if you remember, the pain sensations didn’t start until someone told us we were bleeding AND we found to source of the blood. So the evidence went more like this:

• There was “Sensory” evidence that the brain received from the skin being cut. This absolutely did make it to the brain, but…
• There was no “Witness” evidence as you didn’t notice yourself receiving the cut from a thorn.
• There was no “Visual” evidence at the time as you were distracted and you hadn’t yet notice the cut or seen any blood.
• There was no “Sound”, “Smell” or “Taste” evidence in this scenario.
• The “Auditory” evidence came eventually, when you were informed by a friend/partner that you were bleeding. But there is still no pain sensation happening because you still needed to prove they weren’t pulling your leg!
• The”Visual” evidence came after when you looked at the blood, traced it back to the source, and saw the cut.
• Then you got “knowledge” evidence from knowing that a cut can lead to an infection.
• Then you got “Imagined” evidence as you started to think about how this might affect your health/work/commitments etc.
• Then the pain conversation starts and the area starts to sting or throb!

And the thing is, if the cut is tiny and it doesn’t concern you, then you still may not even start the pain conversation. But if the cut is concerning to you, or you simply just hate the sight of blood, the pain conversation will kick in and could be quite significant. You may even faint!

This is one of those situations where evidence was missed or even ignored, so the pain conversation never started. This scenario shows how pain is not coming from damaged tissues but instead from your computation of danger related to those tissues.

If you see the cut and you’re not really concerned, then the pain you feel will be small or even non-existent. But if you are concerned, the pain will be at the level of that concern because suddenly your brain has lots of evidence of danger.

This is important to understand because it points to why pain scientists see increased levels of pain, and greater chances of pain becoming persistent, in people with anxiety over their body.

(notice I said “anxiety over their body”, not “anxious people”. Remember, the statement about pain refers to “danger to the body” not general anxiety. This is why people that otherwise don’t suffer from anxiety can faint at the sight of their own blood –– fainting is another word in the language of pain.)

So this scenario begins to introduce the weirdness of “evidence” and how the brain concludes danger. But nothing is more weird then the next scenario.

The Carpenter’s Foot Pain Conversation.

Now this is the version of a pain conversation that really shows why it’s all about credible evidence. Remember there was actually no tissue damage at all, but there was credible evidence that their should be.

• There was no “sensory” nerve endings damaged from damaged tissue giving evidence of danger to the brain. BUT…
• There was “Witness” evidence as the carpenter was clearly conscious of the event.
• And there was “Visual” evidence as he was wide–eyed, looking at the nail through his boot.
• And there was “Audio” evidence of hearing the nail gun go off.
• And there was “Knowledge” evidence because the guy knows the dangers of a nail gun.
• And there was “Imagined” evidence as the guy imagines what might have happened to the foot.
• And there was also “Imagined” evidence as he tries to predict how this might impact his income, or ability to play sports, or walk his dog, or climb a ladder, or be made fun of at work etc.

Like the stubbed toe scenario, there is lots of credible evidence here to give good reason for the pain conversation to start up.

But damage to the body is being assumed because the nail never broke the skin! The brain has concluded damage to the body, yet has completely ignored what sensory feedback it is actually getting from the body –– which is nothing! That’s a bit nuts if you think about it.

We all assume that if we have pain then the body must be damaged in some way. Yet in persistent pain this is rarely the case.

So when you see a good Pain Coach or therapist who understands the language of pain, they may tell you that your pain is not due to actual damage. They’re not going mad. They’re likely making a good assessment of the facts.

Okay, Time For Another Recap…

We started this chapter by asking a few questions: How do we make more sense of this conversation the brain is having, that we call “pain”? How do we know when the conversation will start? And possibly even––how can we bring the conversation to a close?

We can now answer all these questions in one simple statement. The first two like this:

“Pain occurs when the brain concludes there is more credible evidence of danger related to the body than credible evidence of safety related to the body.”

And the last, and arguably more important question we can answer by flipping the statement around:

“Pain SUBSIDES when the brain concludes there is more credible evidence of SAFETY related to the body than credible evidence of DANGER related to the body.”

See how this statement can work in our favour too? It actually tells us exactly how to bring the conversation to a close –– we gather evidence of safety.

Which is the topic of our next chapter –– Building A Case For Safety.

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