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Human and Machine Consciousness

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David Gamez

4. The Measurement of Consciousness

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  • 1 Chalmers (1998, p. 220.)

Consciousness just is not the sort of thing that can be measured directly. What, then, do we do without a consciousness meter? How can the search go forward? How does all this experimental research proceed?
I think the answer is this: we get there with principles of interpretation, by which we interpret physical systems to judge the presence of consciousness. We might call these preexperimental bridging principles. They are the criteria that we bring to bear in looking at systems to say (1) whether or not they are conscious now, and (2) which information they are conscious of, and which they are not.
David Chalmers, On the Search for the Neural Correlates of Consciousness1

4.1 First-Person Reports about Consciousness (C-Reports)

1I am standing with my friend Olaf in a field of poppies. ‘Look Olaf,’ I say, ‘the poppies are red, the sky is blue and the leaves are green.’ ‘By the blood of Grendel,’ he replies, ‘I can hear the sound of a bird singing and feel a sensation of warmth in my left foot.’

  • 2 Descriptions of consciousness can be interpreted as statements about the physical world. When I re (...)

2In earlier times my chat with Olaf would have been interpreted as a conversation about the world. Over the last three hundred years science has sucked colour, sound and warmth out of the world and reinterpreted them as consciousness. Statements like ‘The poppies are red’ or ‘There is a rusty helmet on the ground’ have become descriptions of consciousness.2

  • 3 Wittgenstein (1969) discusses how our knowledge is underpinned by a framework of certainties that (...)

3I am certain that I can speak about my consciousness. I cannot doubt that ‘The poppies are red’ is a true statement about my bubble of experience. I would be more willing to jettison the entire edifice of science, than abandon my belief that I can describe my consciousness.3

  • 4 When we imagine different motor tasks, such as walking around a house or playing tennis, we activa (...)

4I can speak about my consciousness. I can describe my consciousness by pushing buttons and pulling levers. I can reply to questions about my consciousness by putting my brain into different states in a fMRI scanner.4

  • 5 This list of behaviours includes suggestions from Shanahan (2010), Koch (2004) and Teasdale and Je (...)
  • 6 Post-decision wagering is a method that is used to measure consciousness in psychology (Persaud et (...)
  • 7 An overview of some of the techniques for measuring consciousness is given by Seth et al. (2008.)

5Olaf is alert. He can flexibly respond to novel situations. He can inwardly execute a sequence of problem-solving steps. He can execute a delayed reaction to a stimulus and respond to verbal commands.5 He is willing to bet a large amount of money that there is a rusty helmet in the field of poppies.6 These behaviours can be used to make reliable inferences about the contents and level of Olaf’s consciousness, even when he is not explicitly reporting his consciousness.7

6I punch Olaf in the face. He falls to the ground and lies still. His stillness and lack of response are external signs that his brain is not associated with a bubble of experience, that his level of consciousness is zero.

7When Olaf regains consciousness he exhibits groggy behaviour. l interpret this as a sign that he has a low level of consciousness. He is never quite the same again and often behaves in a similar way to a patient described by Damasio:

  • 8 Damasio (1999, p. 6).

Suddenly the man stopped, in midsentence, and his face lost animation; his mouth froze, still open, and his eyes became vacuously fixed on some point on the wall behind me. For a few seconds he remained motionless. I spoke his name but there was no reply. Then he began to move a little, he smacked his lips, his eyes shifted to the table between us, he seemed to see a cup of coffee and a small metal vase of flowers; he must have because he picked up the cup and drank from it. I spoke to him again and again he did not reply. He touched the vase. I asked him what was going on and he did not reply, his face had no expression. […] Now he turned around and walked slowly to the door. I got up and called him again. He stopped, he looked at me, and some expression returned to his face—he looked perplexed. I called him again and he said, “What?”8

8When Olaf is in this state he is not capable of executing a sequence of problem-solving steps. He does not flexibly respond to novel situations. He cannot execute a delayed reaction to a stimulus. We interpret his behaviour as a sign that he has zero consciousness, that he is not immersed in a bubble of experience.

9Any behaviour that can be interpreted as a measurement of the level and/or contents of a person’s consciousness will be referred to as a c-report:

D2. A c-report is a physical behaviour that is interpreted as a report about a person’s consciousness.

10A c-report is a measurement of consciousness. This measurement is indirect—Olaf’s bubble of experience does not appear in my bubble of experience.

11Indirect measurements are standard scientific practice. When I measure the path of a particle, the particle does not directly appear in my bubble of experience. I have to create an experimental situation in which the particle creates a visible trace, such as a track of bubbles in a chamber. Theories about the physical world link the bubble track to the path of the invisible particle.

4.2 Reports about Non-Conscious Mental Content (NC-Reports)

12Olaf thinks a lot about his sweetheart Olga. As he crosses the field of poppies he is thinking about her corn-blond plaits, her inviting smile, her chequered billowing skirt, her strong smooth thighs. He is not aware of the stones in his boots, the white crosses in the field or the hot sun on his face. None of these are in his bubble of experience, although he could bring them into his bubble of experience if he stopped thinking about Olga’s thighs and focused on his body and surroundings.

13As Olaf walks and thinks about Olga, the sensory data from the field of poppies is used by his brain to generate control signals that are sent to his muscles. This sensory data does not appear in his bubble of experience. It is unconscious or non-conscious information.

  • 9 An overview of binocular rivalry is given by Blake (2001).

14I present a picture of Olga to Olaf’s right eye and a picture of Olaf’s ex-wife Ingrid to his left eye. He experiences a phenomenon called binocular rivalry in which Olga’s picture is perceived for a few seconds while Ingrid’s is non-conscious, and then Ingrid’s picture becomes conscious and Olga’s non-conscious. When Ingrid’s picture is non-conscious it is still being processed by Olaf’s brain, which responds to the shape of her sharp tongue in her hard mouth.9

  • 10 This is a simplified summary of the large number of experiments that have been carried out on visu (...)
  • 11 This is known as forced choice guessing. While some people believe that above chance results on a (...)

15I show Ingrid’s picture to Olaf for 30 ms in the middle of a sequence of scrambled images. Under these conditions Ingrid’s picture does not enter Olaf’s bubble of experience, but it does cause Olaf to complete word fragments with Ingrid-related words and alters the conductivity of his skin.10 When I ask Olaf to guess which picture was shown he picks Ingrid’s picture more often than chance.11

16All of these behaviours can be used to identify mental contents that are being processed non-consciously. They are nc-reports:

D3. A nc-report is a physical behaviour that is interpreted as a report about non-conscious mental content.

4.3 Platinum Standard Systems

17C-reports about consciousness can be found everywhere. The sigh of waves can be interpreted as a c-report. Or consider the following snippet of code:

  1. string input = "";
  2. cout <<"Hello"<<endl;
  3. while (input!= "Goodbye"){
  4. getline (cin, input);
  5. if (input == "Are you conscious?")
  6. cout <<"Yes"<<endl;
  7. else if (input == "Are you a cute leetle kitten?")
  8. cout <<"Yes, my eyes are blue and I cry 'Mew mew mew'."<<endl;
  9. else if (input == " Goodbye")
  10. cout <<"Goodbye"<<endl;
  11. else
  12. cout <<"Nice weather for the time of year."<<endl;
  13. }

18A computer running this code will claim that it is conscious. It will also claim that it is a cute leetle kitten. Neither claim is convincing.

19My wife is a zombie. She hides from light and shuffles home from work with dead eyes, drinks in the pub with dead eyes, makes love with dead eyes. Her physical body is not associated with a bubble of experience. Her zombie statements about ‘consciousness’ are not descriptions of a bubble of experience. They are just empty sounds produced by biochemical processes.

20My wife is a professional phenomenologist. She says many things that appear to be descriptions of a bubble of experience. I cannot directly observe her lack of consciousness, so how can I prove that she is a zombie? How can I prove that other people’s bodies are really associated with bubbles of experience? This is the traditional problem of other minds.

21To scientifically study consciousness we need a physical system that is associated with consciousness. Since it is impossible to prove that particular physical systems are conscious, we have to set aside philosophical worries about solipsism and zombies and assume that one or more physical systems are actually conscious. I will do this by introducing the concept of a platinum standard system:

  • 12 By ‘associated’ it is meant that consciousness is linked to a platinum standard system, but no cla (...)

D4. A platinum standard system is a physical system that is assumed to be associated with consciousness some or all of the time.12

  • 13 The metre used to be defined as one ten-millionth of the distance from the Earth’s equator to the (...)
  • 14 If the platinum-iridium standard metre doubled in size, an object that used to be 1 metre long (1 (...)

22The term ‘platinum standard system’ is a reference to the platinum-iridium bar that was the first working definition of a metre.13 Other objects were directly or indirectly compared to this platinum-iridium bar to measure their length. The length of this bar could not be checked because it was defined to be one metre long: when this bar expanded, everything else contracted.14

23Platinum standard systems are the starting point for consciousness science. Consciousness is simply assumed to be associated with these systems. When we have identified the relationship between consciousness and the physical world in platinum standard systems, we can use this knowledge to make inferences about the consciousness of other systems.

24I was awarded a grant to study consciousness and ordered a platinum standard system from the supplier. It was delivered yesterday. I poured myself a coffee and strolled over to inspect it. A decent enough specimen with a bushy red beard, around 2 m tall. It made angry noises and rattled the bars of its cage. I prodded it with a stick and topped up its bowl of brown nuggets.

25The supplier states that this system is associated with a bubble of experience. They are a reputable firm, so I have confidence in their claim. On the first day of our experiments we strapped the platinum standard system into a chair, held up a red apple and asked it for a c-report. It stated that it was conscious of a red apple. A promising start, but it had a crafty look in its eye—it might have been lying. Or its consciousness might be a delusional world that is completely disconnected from its behaviour. I was assured that this system shipped with a bubble of experience, but the supplier did not guarantee that I would be able to use c-reports to measure its bubble of experience.

26Scientists studying consciousness need to measure consciousness. While a platinum standard system’s c-reports can be cross-checked for consistency, there is no ultimate way of establishing whether they are correct. Since c-reports are the only way in which consciousness can be measured, it has to be explicitly assumed that c-reports from a platinum standard system co-vary with its consciousness:

A1. During an experiment on consciousness, the consciousness associated with a platinum standard system is functionally connected to the platinum standard system’s c-reports.

  • 15 Functional connectivity (a deviation from statistical independence between A and B) is typically c (...)

27A functional connection between consciousness and c-reports is a deviation from statistical independence—not necessarily a causal connection.15

  • 16 While phenomenal consciousness and access ‘consciousness’ might be conceptually dissociable (Block (...)

28A1 captures the idea that our consciousness is connected to our c-reports. When our consciousness changes, our c-reports change. This assumption does not specify the amount of functional connectivity between consciousness and c-reports, which will vary with the type of c-reporting. A1 is also explicitly limited to experiments on consciousness.16

29Outside of experiments on consciousness it is possible that a system’s consciousness could be disconnected from its behaviour. Information gathered by consciousness experiments could be used to make inferences about the presence of consciousness in these situations. It could also be used to make deductions about the consciousness of systems that are not platinum standards, such as brain-damaged patients (see Section 9.2).

30I contact the supplier. They issue me with a certificate that guarantees that their platinum standard systems’ c-reports are functionally connected to their consciousness (A1). We resume our experiments and identify a neural firing pattern that always occurs when the platinum standard system is conscious, and never occurs when it is not conscious. We have found the correlates of consciousness! We write up the results and submit our paper for publication.

31The paper is rejected. We are devastated and enraged. One reviewer argues that our platinum standard system could have several consciousnesses. The second reviewer suggests that its bubble of experience could have features that are impossible to c-report under any circumstances. The third reviewer points out that it might be conscious when it is not c-reporting—it would just be unable to remember or report its consciousness. At best we have identified a correlate of part of its consciousness, not a true correlate of consciousness.

32The systematic study of consciousness will be difficult or impossible if platinum standard systems are potentially associated with ghostly ecosystems of unreportable consciousnesses, or if many aspects of consciousness cannot be c-reported. Scientific studies have to assume that this is not the case:

  • 17 A possible exception to this would be a situation in which non-reportable consciousness is present (...)

A2. During an experiment on consciousness all conscious states associated with a platinum standard system are available for c-report and all aspects of these states can potentially be c-reported.17

  • 18 This is similar to Block’s (2007) idea of cognitive accessibility.
  • 19 Dennett questions the idea that there is a single stream of consciousness with a fixed content: ‘t (...)

33This assumption states that every aspect of all of the conscious states that are associated with a platinum standard system can potentially be c-reported, even if they are not actually reported during an experiment.18 So we can use a variety of c-reports to extract a complete picture of a platinum standard system’s consciousness (see Section 4.8).19

  • 20 Panpsychism is the view that all matter is linked to consciousness. For example, some versions of (...)
  • 21 A2 is also likely to be incompatible with Zeki and Bartels’ (1999) proposal that micro-consciousne (...)

34A2 is incompatible with panpsychism.20 If all matter is conscious all the time, then c-reports cannot be used to measure all of a platinum standard system’s consciousness. If panpsychism was true, an apparently unconscious brain that was c-reporting zero consciousness would be associated with a bubble of experience.21

4.4 Pinning Consciousness to the Physical World

  • 22 The perceived colour of an object does not just depend on the frequencies of the electromagnetic w (...)

35When I was a lad my father shone 700 nm light into my eyes and said ‘Red … red … red.’ My mother shone 450 nm light into my eyes and said ‘Blue … blue … blue.’ At a later point in time I c-report that there is a red patch in my bubble of experience. To make this report I use the association that I have learnt between an experience and a word. When I say that I am conscious of the red patch I am saying that I am having approximately the same colour experience that I had when I learnt the word ‘red’. The incoming electromagnetic waves have activated the same brain areas that were activated when I learnt the word ‘red’ as a child, which presumably are associatively linked to particular language or conceptual areas. My description of my conscious experience is a comparison with earlier experiences.22

36We are sitting in a bare whitewashed room. A human ear is on the table in front of us. The colour of the torn edge of the ear is similar to the colour that I experienced when my father shone 700 nm light into my eyes. I make a c-report: ‘I am experiencing the colour red.’ The colour of the torn edge of the ear in your bubble of experience is similar to the colour that you experienced when your father shone 700 nm light into your eyes. You make a c-report: ‘I am experiencing the colour red.’

  • 23 There are likely to be subtle behavioural differences between two colour-inverted people—see Palme (...)

37We both report that we are experiencing ‘red’, so we are apparently having the same conscious experience. But what if the colour produced by 700 nm electromagnetic waves in my bubble of experience is completely different from the colour produced by 700 nm electromagnetic waves in your bubble of experience? We have learnt the same mapping between incoming electromagnetic wave frequencies and colour names, so we will both make identical reports about the electromagnetic waves that we are exposed to, but nothing guarantees that these reports correspond to identical colour experiences. This is the classic problem of colour inversion, which is illustrated in Figure 4.1.23

Figure 4.1. Problem of colour inversion. a) A person teaches us the word ‘red’ by pointing to a coloured patch and making the sound ‘red’. Your colours are inverted relative to mine, so my red is your turquoise, and so on. We both learn to associate the colour that we experience with the sound ‘red’. b) We observe a severed ear on a table. The colour of the torn edge of the ear is similar to the colour that we experienced when we learnt the word ‘red’, so we both report that we are experiencing the colour red. The colours in our bubbles of experience are very different, but there is no way of detecting this in our external behaviour. Image © David Gamez, CC BY 4.0.

38In the standard colour inversion scenario a single set of colours is linked in different ways to electromagnetic waves. Our bubbles of experience could also contain completely different sets of ‘colours’ that have no overlap between them. Or our consciousnesses could be different in more radical ways—different geometries, different experiences of space and time, differences that I am unable to imagine because I cannot imaginatively transform my bubble of experience into these other states.

39In these scenarios two systems in similar physical states are associated with radically different bubbles of experience. Since they are making the same c-reports the differences between their bubbles of experience will not show up in scientific experiments. It will be impossible to systematically study the relationship between consciousness and the physical world under these conditions.

  • 24 If a set of properties, A, supervenes on another set of properties, B, then it is impossible for t (...)

40To address this issue scientists studying consciousness have to assume that identical states of the physical world are associated with identical conscious states. This can be expressed using the philosophical concept of supervenience.24 Since we are only concerned with a pragmatic approach to the science of consciousness, it is not necessary to assume that consciousness logically or metaphysically supervenes on the physical world. We just need to assume that the natural laws are such that consciousness cannot vary independently of the physical world:

A3. The consciousness associated with a platinum standard system nomologically supervenes on the platinum standard system. In our current universe, physically identical platinum standard systems are associated with indistinguishable conscious states.

4.5 Which Systems are Platinum Standards?

  • 25 Kouider et al. (2013) and Dehaene (2014) discuss infant consciousness.
  • 26 Animal consciousness is discussed by Dehaene (2014), Edelman and Seth (2009) and Feinberg and Mall (...)
  • 27 People with Anton-Babinski syndrome are blind, but claim that they can see and confabulate to cove (...)

41It is not known when consciousness emerges in the embryo or infant.25 We do not know whether birds or cephalopods are conscious.26 Brain-damaged people can inaccurately report their consciousness.27 No-one knows whether computers are capable of consciousness. We try and fail to use our imagination to decide whether consciousness is present in these systems.

42I am an adult. I can smoke, drive and vote. Ten doctors claim that my brain is functioning normally. My brain does not contain unusual chemicals that might affect its operation. I am certain that this normally functioning adult human brain is associated with consciousness some of the time. If consciousness supervenes on the physical world (A3), then similar brains will be associated with similar consciousness:

  • 28 Section 2.4 discusses theories that link consciousness to sensorimotor interactions between the br (...)

A4. The normally functioning adult human brain is a platinum standard system.28

  • 29 Although brain-damaged patients have played an important role in consciousness research, they shou (...)

43The normally functioning adult human brain is the only system that we confidently associate with consciousness. At a later point in time we might make further assumptions that extend the number of platinum standard systems. For example, we might assume that the red nodules on the genitals of an alien race are platinum standard systems.29

Figure 4.2. Some of the definitions and assumptions that are required for scientific experiments on consciousness. The normally functioning adult human brain is a platinum standard system (A4), which is associated with consciousness (D4). Consciousness nomologically supervenes on the platinum standard system (A3) and all of it can be c-reported (A1, A2). Image © David Gamez, CC BY 4.0.

44The science of consciousness is limited by the set of systems that we assume to be platinum standards. It is a science of the relationship between consciousness and platinum standard systems. Many relationships between consciousness and the physical world might not appear in normally functioning adult human brains. This would reduce the accuracy of our deductions about consciousness in non-human systems (see Section 9.2).

45Some of the definitions and assumptions that have been introduced so far are illustrated in Figure 4.2.

4.6 The Correlates of a Conscious State

46Yesterday I lost consciousness in the street. My body lay crumpled on the concrete. Insects crawled over my face. Cappuccino-carrying commuters stepped over me on the way to the office. My body was just a thing—a part of the physical world that was not associated with a bubble of experience.

47I am conscious now. The state of my brain now is different from the state of my brain when I lay unconscious on the street. If consciousness supervenes on the physical world (A3), something must be present in my brain now that is absent when consciousness is absent. This is a correlate of consciousness, which is defined as follows:

  • 30 The notion of a minimal set is intended to exclude features of the brain that typically occur at t (...)
  • 31 This is similar to Chalmers’ (2000) definition of the total correlates of consciousness, which he (...)

D5. A correlate of conscious state is a minimal set30 of one or more spatiotemporal structures in the physical world. This set is present when the conscious state is present and absent when the conscious state is absent. This will be referred to as a CC set.31

48‘Spatiotemporal structures’ is a deliberately vague term that captures anything that might be correlated with consciousness, such as activity in brain areas, electromagnetic waves or quantum events. Chapters 6–8 discuss some of the spatiotemporal structures that might be members of CC sets.

  • 32 This will not be correct if some spatiotemporal structures can inhibit consciousness. For example, (...)

49Correlates defined according to D5 will be associated with consciousness wherever they are found.32 Suppose CC sets only contain electromagnetic wave patterns. When a particular electromagnetic wave pattern occurs in your brain, you are immersed in a particular bubble of experience. When the electromagnetic wave pattern is absent, you have a different bubble of experience or no consciousness at all. None of the other types of spatiotemporal structure in your brain have any effect on your bubble of experience.

50I distract you with a soft toy: ‘Here reader, look at this, look… look… look at Teddy.’ While you are playing with its ears I extract your brain from your skull and keep it alive in a jar. I provide stimulation patterns that mimic the sensory-motor responses of your discarded body. I ensure that the electromagnetic wave pattern in your brain is identical to the one that was present when you were playing with Teddy. This is associated with a bubble of experience in which you are playing with Teddy, so you continue to have this experience.

51I discard your brain’s biological tissue and replace it with silicon chips that are programmed to produce the same pattern of electromagnetic waves. You remain contentedly unaware of what is going on and continue to play with Teddy’s ears in your bubble of experience. Suppose that the same pattern of electromagnetic waves occurs by chance when I drop my phone. This will also be associated with a bubble of experience in which you are playing with Teddy’s ears.

52Definition D5 enables me to state assumption A3 more precisely:

A3a. The bubble of experience that is associated with a CC set nomologically supervenes on the CC set. In our current universe, physically identical CC sets are associated with indistinguishable conscious states.

  • 33 Footnote 15 explains the relationship between functional and effective connectivity. These are typ (...)

53A correlation between A and B is the same as a functional connection between A and B—they are different ways of stating that A and B deviate from statistical independence.33 So a CC set can be described as a set of spatiotemporal structures that is functionally connected to a conscious state. This way of describing the relationship between consciousness and the physical world will play a role in what follows, so it will be formally stated as a lemma:

  • 34 There are many spurious correlations—for example, see Vigen (2016). These can be divided into fals (...)

L1. There is a functional connection between a conscious state and its corresponding CC set.34

4.7 A Causal Relationship between Consciousness and the Physical World?

  • 35 Kim (1998, p. 31).

A science that invokes mental phenomena in its explanations is presumptively committed to their causal efficacy; for any phenomenon to have an explanatory role, its presence or absence in a given situation must make a difference—a causal difference.
Jaegwon Kim, Mind in a Physical World35

54I was looking for love on the Internet. ButiDD’s profile looked promising: witty lines, sexy curves, hot pics. We arranged a date on Friday 5 August 2005 at 15:00 in a cafe on Hampstead Heath. When we met there was no chemistry. Conversation ground to a halt. I ate my cake. To cut through the boredom and silence I remarked ‘I am conscious of a sweet taste in my mouth.’ These sound vibrations led, through a complex chain of causes and effects, to Hurricane Katrina.

55C-reports have physical effects. Speech vibrates the air, writing makes marks, gestures depress buttons and pull levers. These physical effects lead to further chains of causes and effects, which can be amplified into a hurricane or dissolve into background noise. Consciousness appears to be the source of c-reports, so it is natural to assume that it is the sort of ‘thing’ that can cause effects in the physical world.

  • 36 This distinction is taken from Dowe (2000). It is similar to Fell et al.’s (2004) distinction betw (...)
  • 37 Predominantly conceptual accounts of causation include Lewis’ (1973) counterfactual analysis and M (...)

56A clearer definition of causation will help us to understand the relationship between consciousness and c-reports. First I will distinguish between conceptual and empirical theories of causation.36 Conceptual theories of causation elucidate how we understand and use causal concepts in our everyday speech. Empirical theories of causation explain how causation operates in the physical world—by reducing it to the exchange of physically conserved quantities, such as energy and momentum, or linking it to physical forces.37

57Conceptual analyses of causation are popular in philosophy, but it is difficult to see how our use of ‘causation’ in everyday speech can help us to understand the causal interactions in the brain’s neural networks and the relationship between consciousness and the physical world.

58Empirical theories of causation can precisely identify causal events and exclude cases of apparent causation between correlated events. They can easily relate the causal laws governing macro-scale objects, such as cars and people, to the micro-scale interactions between molecules, atoms and quarks. Empirical theories of causation are a much more appropriate starting point for studying the causal relationships between consciousness and c-reports.

  • 38 See Dowe (2000).

59A detailed discussion of the advantages and disadvantages of different theories of empirical causation is beyond the scope of this book, but it will be easier to analyze the c-reporting of consciousness with a concrete theory in mind. For this purpose I will use Dowe’s theory of empirical causation. This is the most fully developed conserved quantities approach and it has the following key features:38

  • A conserved quantity is a quantity governed by a conservation law, such as mass-energy, momentum or charge.
  • A causal process is a world line39 of an object that possesses a conserved quantity.
  • A causal interaction is an intersection of world lines that involves the exchange of a conserved quantity.
  • 40 If all empirical theories of causation are unworkable, then we might have to limit causal concepts (...)

60This account of causation will be referred to as e-causation. The framework developed in this book relies on there being some workable theory of e-causation, but it does not depend on the details of any particular account. If Dowe’s theory is found to be problematic, an improved version can be substituted in its place.40

61A car moves along a road at 5 m/s and knocks a fat man down (Figure 4.3a). In this e-causal interaction energy-momentum is transferred from the car to the man. This macro-scale e-causal interaction can be reduced down to the micro-scale e-causal interactions between the physical constituents of the car and man, in which atoms in the car’s bumper pass energy-momentum to atoms in the man’s legs (Figure 4.3b).

  • 41 Kim (1998) has a good discussion of the relationship between macro and micro physical laws.

62We can distinguish between true and false causes of this event. The car’s engine temperature is a macro-scale property of the physical world that moves along at the same speed as the car and also collides with the man (Figure 4.3c). However, the macro property of engine temperature does not exchange energy-momentum with the man, so it does not e-cause him to fall down, although it can e-cause other macro-scale effects, such as skin burns. Similar e-causal accounts can be given of the laws of other macro-scale sciences, such as geology, chemistry and biology.41

Figure 4.3. The relationship between macro-and micro-scale e-causal events. a) A car moving at 5 m/s collides with a fat man and knocks him down. This is a macro-scale e-causal event in which the car passes energy-momentum to the man. b) The macro-scale e-causal interaction between the car and man can be reduced down to the micro-scale exchanges of energy-momentum between atoms in the car and man. c) The temperature of the car’s engine is a macro-scale property that moves at 5 m/s and collides with the man. The engine temperature exchanges a small amount of energy-momentum with the man in the form of heat, but not enough to e-cause him to fall down. Image © David Gamez, CC BY 4.0.

63It is generally assumed that the amount of energy-momentum in the physical universe is constant (as long as the reference frame of the observer remains unchanged). When part of the physical world gains energy-momentum, this energy-momentum must have come from elsewhere in the physical universe. It is also generally assumed that the net quantity of electric charge in the universe is conserved. If part of the physical world gains electric charge, another part of the physical world must have lost charge or there must have been an interaction in which equal quantities of positive and negative charge were created or destroyed. Similar arguments apply to other physically conserved quantities, which leads to the following assumption:

A5. The physical world is e-causally closed.

64According to A5, any change in a physical system’s conserved quantities can in principle be traced back to a set of physical e-causes that led the system to gain or lose those conserved quantities at that time.

65In everyday language we say that a person reports or describes their consciousness. This might naively be interpreted as the idea that consciousness directly or indirectly alters the activity of the brain’s speech areas, sending spikes to the larynx that lead to sound vibrations in the air.

  • 42 Wilson (1999) discusses the minimum amount of physical effect that would be required for conscious (...)
  • 43 A related point is made by Fell et al. (2004), who argue that the neural correlates of consciousne (...)

66The problem with this naive picture is that consciousness could only e-cause a chain of events leading to a c-report if it could pass a physically conserved quantity, such as energy-momentum or charge, to neurons in the c-reporting chain—for example, if it could push them over their threshold and cause them to fire.42 If the physical world is e-causally closed (A5), then a conserved quantity could only be passed from consciousness to a brain area if consciousness is a physical phenomenon, i.e. if consciousness is the correlates of consciousness.43

67Consciousness is the correlates of consciousness if physicalism is correct. But it would be premature and controversial to base the scientific study of consciousness on this assumption. It is also absurd to claim that a bubble of experience is a pattern of invisible wave-particles. It would be much better to find a way of measuring consciousness that does not depend on the assumption that physicalism is true.

68I have assumed that a conscious state is functionally connected to a CC set (L1) and that c-reports are functionally connected to consciousness (A2). To fully account for the measurement of consciousness we need an e-causal connection between CC sets and c-reports. This can be addressed by introducing a further assumption that fits in naturally with the current framework:

A6. CC sets e-cause a platinum standard system’s c-reports.

  • 44 Controversial experiments by Libet (1985) have indicated that our awareness of our decision to act (...)
  • 45 It is reasonably easy to see how the contents of consciousness that are c-reported could be e-caus (...)

69This states that the correlates of consciousness are the first stage in a chain of e-causation that leads to c-reports about consciousness.44,45 It can be difficult to measure e-causation, so in some circumstances A6 can be substituted for the weaker assumption:

  • 46 See Footnote 15 for the distinction between structural, functional and effective connectivity. Eff (...)

A6a. CC sets are effectively connected to a platinum standard system’s c-reports.46

70Assumption A6 is illustrated in Figure 4.4.

71By themselves A6 and A6a do not say anything about the strength of the relationship between CC sets and c-reports. There could be a very weak e-causal chain leading from a CC set to a c-report, which could primarily be driven by unconscious brain areas. The weaker the connection between CC sets and c-reports, the more experiments will be required to identify CC sets.

  • 47 In the real brain many areas are reciprocally connected to each other and there is a great deal of (...)

Figure 4.4. Assumptions about the relationship between CC sets, consciousness and first-person reports. The labels S1, CC1, R1, etc. refer to any kind of spatiotemporal structure in the brain, such as the activation of a brain area, neural synchronization, electromagnetic waves, quantum events, and so on. They are only illustrative and not intended to correspond to particular anatomical paths or structures. An e-causal chain of sensory spatiotemporal structures, S1-S3, leads to the appearance of a spatiotemporal structure, CC1, that is functionally connected to consciousness. In this example the contents of consciousness are determined by sensory events, but in principle they could be independent of S1-S3—for example, if the subject was dreaming. CC1 is assumed to be the first stage in an e-causal chain of spatiotemporal structures, R1-R3, that lead to a verbal description of consciousness. Image © David Gamez, CC BY 4.0.47

4.8 The Limits of C-Reporting

72You are looking at your reflection in a mirror. You see greying hair, burst capillaries, lengthening deepening lines. A tired sad sagging face. Your youth has gone. You will die soon. A sense of helpless fatality washes over you. You imagine how your face will look in the grave, under the wet earth, your empty eye sockets staring blankly at blackness, while the world rolls along and your existence fades away without trace.

  • 48 Cohen and Dennett (2011) illustrate the low resolution of our peripheral vision.

73Stick up your thumbs and interlace your fingers. Extend your arms to their full length in front of you. Look directly at your thumbnails. The area covered by your thumbnails is the high resolution part of your visual field. The rest is low resolution. When you look at your nose in the mirror only sketchy information is coming in from your gold earrings and beard. You cannot detect substantial changes that occur outside of the high resolution area.48

  • 49 Our ability to access high resolution information on demand contributes to our sense that we perce (...)

74The limited extent of our high resolution vision is not a problem in daily life. When we require more information about a feature of our environment we make a rapid eye movement (known as a saccade) to bring this feature into high resolution vision. As you look in the mirror you are moving your eyes every ~200 ms. You inspect the pores on your nose, flick across to your left cheek, look up at your eyebrow, and so on.49

75Depressed you pluck out a protruding hair. You squeeze a painful spot and wipe a stain from the mirror. A chewed-up cabbage leaf is trapped between your teeth. You remember your dental appointment tomorrow.

  • 50 This is a conservative estimate based on eye-movement driven changes and the assumption that consc (...)

76Your consciousness changes several times per second.50 As you look at your face in the mirror you are receiving fresh sensory information from your eyes and body and attending to different senses (moving from vision, to touch, to audition, etc.). You are shifting between past, present and possible futures: between memory, perception and imagination.

77Describe your consciousness now. You were in a reverie—try again. The clock reads 22:59:50.874. Describe your consciousness when it changes to 23:00:00.000. Get ready … now.

78When you started to describe your consciousness you were alert and speaking coherently. This external behaviour was a c-report of a high level of consciousness. Immobility and incoherent mumbling would have been a c-report of a low level of consciousness.

79When the clock changed to 23:00:00.000 you started to describe your consciousness in natural language. But your consciousness changed when you uttered the first word—it became consciousness of that word. The consciousness that you had at 23:00:00.000 vanished when you started to describe it. Natural language is too slow to c-report consciousness in real time.

80Ok, try a different strategy. The clock reads 23:01:46.340. Describe your consciousness when it changes to 23:02:00.000. Get ready … now.

81This time you tried to remember your state of consciousness at 23:02:00.000. You converted an online bubble of experience into an offline bubble of experience. This memory preserves some washed-out unstable information about the visual consciousness that you had at 23:02:00.000. It holds little detail about the sounds, smells, tastes and body sensations that were in your bubble of experience at that moment. Your memory is also fragile—it is not like a computer file. As you describe your memory of your consciousness at 23:02:00.000 it becomes contaminated with details that came before or after the moment that you are trying to remember.

82One more attempt. The clock reads 23:05:51.087. Describe your consciousness when it changes to 23:06:00.000. Get ready… now.

  • 51 See O’Regan (1992).

83You could not accurately remember what your nose looked like at 23:06:00.000. So when I asked you to describe your consciousness you moved your eyes to look at your nose. You used the world as external memory.51 Your face is pretty stable, so perhaps you could use this method to generate a complete description of your consciousness at 23:06:00.000. However, this would not provide a description of your consciousness at 23:06:00.000: it would be a description of a series of moments of consciousness in which different aspects of your face enter the high resolution part of your bubble of experience. When you moved your eyes to obtain information about your nose, your consciousness at 23:06:00.000 was replaced with a new bubble of experience in which you were ‘zoomed in’ on your nose.

  • 52 People can be trained to make more accurate reports about their consciousness (Lutz et al. 2002) a (...)

84We cannot accurately describe a state of our consciousness. Natural language is too slow and vague. Our memory does not store enough details. Our consciousness at a given moment cannot be reconstructed by re-accessing information from our environment.52

85Fixate your eyes on the small cross in the centre of the screen. Rest your index finger on the button in front of you. When I say ‘now’ I want you to press the button if there is a small red square in the bottom left hand corner of your visual field. Get ready … now.

86Under controlled experimental conditions I can extract a small amount of accurate information about a specific aspect of your consciousness at a given time. The details of the measurement are set by the experimental conditions. The subject is only required to answer a simple yes/no question, without any need for memory or natural language.

  • 53 Shanahan (2010) suggests how an omnipotent psychologist could measure a person’s consciousness by (...)

87This measurement method has the limitation that a subject can only answer one or two yes/no questions before their consciousness changes. This problem can be partly overcome by resetting their consciousness after each measurement. We can then use a large number of high precision probes to obtain a detailed measurement of one state of a subject’s consciousness.53

  • 54 Mental techniques could also be used to reset consciousness. For example, people with a high level (...)

88As an example, consider an experiment that measures a subject’s visual consciousness. To begin with the subject is asked to fixate on a cross on a screen. When they are looking at the cross it is replaced with a picture that remains on the screen for 200ms. This is long enough to ensure that the subject becomes conscious of the picture, and short enough to prevent them from moving their eyes while they are looking at it. The brief exposure attracts their attention—reducing the chance that their visual consciousness is remembering or imagining something else. The subject’s fixation on the cross ensures that their bubble of experience contains the same part of the picture each time. When the subject’s visual consciousness is put into this state one aspect of it can be measured with high precision. Repetition of this procedure can be used to progressively build up a detailed description of this state of consciousness.54

  • 55 It might be possible to use what we know about the relationship between a stimulus and consciousne (...)

89High precision measurement combined with the resetting of consciousness under experimental conditions is the most promising method for obtaining detailed descriptions of consciousness. But there are limits to the types of consciousness that can be reset, and a subject’s consciousness cannot be put into exactly the same state each time. These problems will reduce our ability to obtain detailed accurate measurements of consciousness.55

4.9 Formal Descriptions of Consciousness (C-Descriptions)

  • 56 Nagel (1974, p. 449).

At present we are completely unequipped to think about the subjective character of experience without relying on the imagination—without taking up the point of view of the experiential subject. This should be regarded as a challenge to form new concepts and devise a new method—an objective phenomenology not dependent on empathy or the imagination. Though presumably it would not capture everything, its goal would be to describe, at least in part, the subjective character of experiences in a form comprehensible to beings incapable of having those experiences.
Thomas Nagel, What Is It Like to Be a Bat?56

90Alice and Bob measure your consciousness at 14:02:00.050 and submit written reports of the results. Alice’s report contains several thousand words of natural language, similar to the work of Husserl, Heidegger and Merleau-Ponty. Bob’s report contains natural language descriptions of the experimental probes that he ran on your consciousness. It is written in the style of a methods section in a paper on experimental psychology. When you read either of these reports you are satisfied that they are a complete and accurate description of your consciousness at 14:02:00.050.

  • 57 You might think that you could validate the descriptions by resetting your consciousness to the st (...)

91This verification process is inexact. It relies on an inaccurate memory of your state of consciousness. It is far from a complete validation. But it will have to do—it is all we can do.57

  • 58 Formal descriptions of the physical world are covered in Section 5.1.

92Formal descriptions play an important role in science. We have formal descriptions of many aspects of the physical world (mass, charge, voltage, magnetic field, etc.) that can be used to generate testable predictions. The Earth and Sun can be described as point masses of 5.97 × 1024 kg and 1.99 × 1030 kg. We can use this description of the Earth and Sun to predict the gravitational force between them (by substituting the masses for m1 and m2 in Newton’s equation F=Gm1m2/r2).58

93Scientific theories of consciousness will eventually use mathematics to map between descriptions of consciousness and descriptions of the physical world (see Section 5.5). This will enable us to make strong testable predictions about the conscious state that is associated with a physical state. This will only become possible when consciousness can be described in a formal way that can be manipulated by algorithms and mathematical equations. This will be referred to as a c-description:

D6. A c-description is a formal description of a conscious state.

94C-descriptions must be compatible with mathematics and they must be applicable to both human and non-human consciousness. We will have to develop methods for converting c-reports into c-descriptions and vice versa.

  • 59 These problems are discussed by Chrisley (1995a) and Gamez (2006).

95Natural language cannot be used for c-descriptions. It is vague, ambiguous, highly compressed and context dependent. Natural language descriptions of consciousness are difficult to analyze with algorithms and it is not obvious how they can be integrated with mathematical equations. Natural language also cannot be used to describe the consciousness of non-human systems, such as infants, bats or robots.59

  • 60 The use of XML to describe consciousness is discussed by Gamez (2006; 2008a).

96C-descriptions could be written in a markup language, such as XML or LMNL. Markup languages are more precise and tightly structured than natural language, and they can be read by both humans and computers. They can capture complex nested hierarchies, which would enable them to describe the relationships between different parts and aspects of a conscious state.60

  • 61 See Balduzzi and Tononi (2009).

97Mathematics could be used for c-descriptions. For example, Balduzzi and Tononi have suggested how conscious states can be described using high dimensional mathematical structures.61 Other mathematical techniques could be used to describe consciousness, such as category theory or graph theory.

98An adequate c-description format is essential for the scientific study of consciousness. C-descriptions are at a very early stage of development and we are only just starting to explore solutions.

4.10 Summary

99Scientists studying consciousness need to accurately measure conscious states. Consciousness is measured through first-person reports (c-reports), such as speaking or body gestures, which cannot be independently checked. This raises the philosophical problems of zombies, solipsism, colour inversion and the causal relationship between consciousness and the physical world. These problems cannot be solved. They can be neutralized by making assumptions that guarantee that consciousness can be accurately measured. The results of the science of consciousness can then be considered to be true given these assumptions.

100I started by assuming that consciousness is functionally connected to first-person reports (A1). I then assumed that everything about a conscious state can be reported during an experiment and that there are no ghostly consciousnesses floating around that cannot be reported (A2). I handled colour inversion scenarios by assuming that consciousness supervenes on the brain (A3, A3a). First-person reporting does not break the causal closure of the physical world (A5) because reports about consciousness are e-caused by the correlates of consciousness (A6). All of these assumptions apply to systems that are assumed to be conscious (platinum standard systems) during experiments on consciousness. I assumed that normally functioning adult human brains are platinum standard systems (A4).

101Consciousness cannot be described in real time using natural language, so we have to use experimental probes to measure specific aspects of a conscious state, and then reset the state and apply more probes until a complete measurement is obtained. The final output of a measurement of consciousness should be a c-description written in a tightly structured formal language, such as category theory or XML, that will support the development and testing of mathematical theories of consciousness.

102This chapter also introduced the concept of a CC set. A CC set is a set of spatiotemporal structures in the physical world that is correlated with a conscious state (D5). The science of consciousness attempts to develop mathematical theories that describe the relationship between CC sets and conscious states. This is covered in the next five chapters.

Notes

1 Chalmers (1998, p. 220.)

2 Descriptions of consciousness can be interpreted as statements about the physical world. When I report that I have a conscious experience of a rusty helmet beside my conscious experience of my left foot, I am also reporting that there is a rusty helmet beside my left foot in the physical world.

3 Wittgenstein (1969) discusses how our knowledge is underpinned by a framework of certainties that cannot be doubted without putting everything into question.

4 When we imagine different motor tasks, such as walking around a house or playing tennis, we activate different brain areas that can be discriminated in a fMRI scanner. This enables people to answer yes/no questions about their consciousness by imagining that they are performing one of two actions. This method has been used to communicate with patients in vegetative or minimally conscious states, who were incapable of other forms of voluntary behaviour (Monti et al. 2010; Owen et al. 2006.)

5 This list of behaviours includes suggestions from Shanahan (2010), Koch (2004) and Teasdale and Jennett (1974.)

6 Post-decision wagering is a method that is used to measure consciousness in psychology (Persaud et al. 2007). A person is asked to make a decision and to bet on the accuracy of that decision. It is assumed that the person will bet more money on decisions that are based on conscious information. See Sandeberg et al. (2010) for a comparison of post-decision wagering, the perceptual awareness scale and confidence ratings.

7 An overview of some of the techniques for measuring consciousness is given by Seth et al. (2008.)

8 Damasio (1999, p. 6).

9 An overview of binocular rivalry is given by Blake (2001).

10 This is a simplified summary of the large number of experiments that have been carried out on visual masking and non-conscious perception. For example, Dell’Acqua and Grainger (1999) showed that unconsciously perceived pictures influenced subjects’ ability to consciously name pictures and categorize words. Schütz et al. (2007) showed that masked prime words can influence how subjects complete gap words. Merikle and Daneman (1996) played words to patients under general anaesthesia and found that when they were awake they completed word stems with words that they had heard non-consciously. A change in the skin’s conductivity is known as a galvanic skin response, which can indicate that information is being processed unconsciously (Kotze and Moller 1990). Öhman and Soares (1994) showed that subjects’ skin conductance response changed when they unconsciously perceived phobic stimuli, such as pictures of snakes or spiders. A review of experimental work on visual masking and non-conscious perception is given by Kouider and Dehaene (2007).

11 This is known as forced choice guessing. While some people believe that above chance results on a forced choice guessing task demonstrate that conscious information is present, blindsight patients can guess the identity of visual stimuli above chance while reporting no subjective awareness (Weiskrantz 1986). Seth et al. (2008) discuss these issues.

12 By ‘associated’ it is meant that consciousness is linked to a platinum standard system, but no claims are being made about causation or metaphysical identity.

13 The metre used to be defined as one ten-millionth of the distance from the Earth’s equator to the North Pole at sea level. Since this was difficult to measure, a platinum-iridium bar was used instead. Rulers were directly or indirectly calibrated against this bar, which was kept in Paris.

14 If the platinum-iridium standard metre doubled in size, an object that used to be 1 metre long (1 platinum-iridium standard metre bar) would have a new length of 0.5 metres (0.5 platinum-iridium standard metre bars). This would only be strictly true if the platinum-iridium bar was the actual definition of the metre, rather than the working definition. The same argument applies to the actual definition of the metre.

15 Functional connectivity (a deviation from statistical independence between A and B) is typically contrasted with structural connectivity (a physical link between A and B) and from effective connectivity (a causal link from A to B)—see Friston (1994; 2011). A number of algorithms exist for measuring functional connectivity (for example, mutual information), and it can be measured with a delay.

16 While phenomenal consciousness and access ‘consciousness’ might be conceptually dissociable (Block 1995), the idea that non-measureable phenomenal consciousness could be present during experiments on consciousness is incompatible with the scientific study of consciousness. Block’s non-accessible phenomenal consciousness does not appear in c-reports, so everything that Block has ever written or said about it is meaningless or false.

17 A possible exception to this would be a situation in which non-reportable consciousness is present but does not interfere with our ability to identify the correlates of consciousness. This is discussed in more detail in Chapter 9, Footnote 13.

18 This is similar to Block’s (2007) idea of cognitive accessibility.

19 Dennett questions the idea that there is a single stream of consciousness with a fixed content: ‘the Multiple Drafts model avoids the tempting mistake of supposing that there must be a single narrative (the ‘final or ‘published’ draft, you might say) that is canonical—that is the actual stream of consciousness of the subject, whether or not the experimenter (or even the subject) can gain access to it.’ (Dennett 1992, p. 113). Personally I do not find Dennett’s arguments for his multiple drafts model convincing. We will find out if he is correct, because it will be impossible to obtain systematic stable measurements of consciousness.

20 Panpsychism is the view that all matter is linked to consciousness. For example, some versions of panypsychism claim that individual electrons, quarks, etc. are associated with simple bubbles of experience.

21 A2 is also likely to be incompatible with Zeki and Bartels’ (1999) proposal that micro-consciousnesses are distributed throughout the brain.

22 The perceived colour of an object does not just depend on the frequencies of the electromagnetic waves that are reflected, transmitted or emitted by it. Our visual system also uses the spectrum of illuminating light and the colour of surrounding objects to identify an object’s colour, which enables us to attribute the same colour to objects under different lighting conditions. I have used electromagnetic wave frequencies to simplify the presentation of the colour inversion argument, which also applies to a more accurate account of colour perception.

23 There are likely to be subtle behavioural differences between two colour-inverted people—see Palmer (1999) for a discussion of behaviourally equivalent inversion scenarios. These differences would disappear if completely different sets of ‘colour’ experiences were linked to frequencies of electromagnetic waves.

24 If a set of properties, A, supervenes on another set of properties, B, then it is impossible for two things to have different A properties without also having different B properties. This is not a causal relationship.

25 Kouider et al. (2013) and Dehaene (2014) discuss infant consciousness.

26 Animal consciousness is discussed by Dehaene (2014), Edelman and Seth (2009) and Feinberg and Mallatt (2013).

27 People with Anton-Babinski syndrome are blind, but claim that they can see and confabulate to cover up the contradictory evidence. Other anosognosia patients are completely paralyzed on one side, but claim that their body is working perfectly.

28 Section 2.4 discusses theories that link consciousness to sensorimotor interactions between the brain, body and environment. In previous work I made the assumption that the awake normal adult human brain is a platinum standard system (Gamez 2011; Gamez 2012a). The more developed account of c-reports presented in this book makes the assumption that the brain is awake unnecessary—immobility, unresponsiveness, etc. are c-reports of zero consciousness.

29 Although brain-damaged patients have played an important role in consciousness research, they should not be uncritically assumed to be platinum standard systems. There can be ambiguities about whether the damage has knocked out the memory and reporting functions and left the consciousness intact, or knocked out the consciousness and left the memory and reporting functions intact. For example, locked-in patients are thought to be fully conscious, but they are only capable of moving their eyes, and some of the patients studied by Owen et al. (2006) and Monti et al. (2010) are likely to be conscious but unable to display this in their external behaviour. The use of brain-damaged patients in consciousness research has the further problem that the damage is typically non-localized and some brain areas are likely to perform several different functions. One way of addressing this issue is to assume that brain-damaged patients are platinum standard systems on a case-by-case basis, taking the details of the damage into account and its likely impact on memory and/ or reporting.
A similar ambiguity applies to the use of anaesthetics in consciousness research. For example, midazolam, xenon and propofol are used to induce unconsciousness, so that scientists can compare the state of the conscious and unconscious brain (Casali et al. 2013). This raises the question whether the anaesthetic completely removes consciousness, or just paralyzes the body and prevents the subject from remembering and reporting their consciousness. This issue can also be addressed on a case-by-case basis. We can examine the mechanism of each anaesthetic and decide whether it is likely to affect the areas linked to memory and/or reporting. Normally functioning adult human brains containing anaesthetics that do not affect memory and/or reporting can be assumed to be platinum standard systems.
Animal experiments can also be handled on a case-by-case basis. We can assume that the brains of monkeys or mice are associated with consciousness, so that we can use these animals in consciousness research.

30 The notion of a minimal set is intended to exclude features of the brain that typically occur at the same time as consciousness, whose removal would not lead to the alteration or loss of consciousness. For example, a CC set might have prerequisites and consequences (Aru et al. 2012; de Graaf et al. 2012) that typically co-occur with consciousness, but the brain would be conscious in exactly the same way if the CC set could be induced without these prerequisites and consequences.

31 This is similar to Chalmers’ (2000) definition of the total correlates of consciousness, which he distinguishes from the core neural basis: ‘A total NCC builds in everything and thus automatically suffices for the corresponding conscious states. A core NCC, on the other hand, contains only the “core” processes that correlate with consciousness. The rest of the total NCC will be relegated to some sort of background conditions required for the correct functioning of the core.’ (Chalmers 2000, p. 26). Block (2007) makes a similar distinction.

32 This will not be correct if some spatiotemporal structures can inhibit consciousness. For example, we might have a CC set, cc1, that is a correlate of consciousness according to D5. In most circumstances consciousness would be present whenever cc1 was present. However, if consciousness was inhibited by ih1, then there could be a situation in which cc1 and ih1 were present together and there was no consciousness.

33 Footnote 15 explains the relationship between functional and effective connectivity. These are typically inferred from data using algorithms, such as Granger causality or mutual information, and they are distinct from physical causation, which is discussed in the next section.

34 There are many spurious correlations—for example, see Vigen (2016). These can be divided into false correlations, which are the result of poor statistical procedures, and true but unlikely correlations that might be due to an underlying cause. When there is a true correlation between A and B it is possible to obtain information about B by measuring A and vice versa (the amount of information that one can obtain depends on the strength of the correlation). In this book I am presenting a framework that is based the assumption that there is a true statistical correlation (functional connection) between consciousness and the physical world. So we can obtain information about consciousness by measuring parts of the physical world and obtain information about the physical world by measuring consciousness.

35 Kim (1998, p. 31).

36 This distinction is taken from Dowe (2000). It is similar to Fell et al.’s (2004) distinction between efficient and explanatory causation. Efficient causation is concerned with the physical relation of two events and the exchange of physically conserved quantities. Explanatory causation refers to the law-like character of conjoined events.

37 Predominantly conceptual accounts of causation include Lewis’ (1973) counterfactual analysis and Mackie’s (1993) INUS conditions. Empirical theories based on the exchange of physically conserved quantities have been put forward by Aronson (1971a; 1971b), Fair (1979) and Dowe (2000). Bigelow et al. (1988) and Bigelow and Pargetter (1990) link causation to physical forces.

38 See Dowe (2000).

39 A world line is the path of an object through space and time.

40 If all empirical theories of causation are unworkable, then we might have to limit causal concepts to ordinary language and abandon the attempt to develop a scientific understanding of the causal relationship between consciousness and the physical world.

41 Kim (1998) has a good discussion of the relationship between macro and micro physical laws.

42 Wilson (1999) discusses the minimum amount of physical effect that would be required for consciousness to influence the physical brain.

43 A related point is made by Fell et al. (2004), who argue that the neural correlates of consciousness cannot e-cause conscious states.

44 Controversial experiments by Libet (1985) have indicated that our awareness of our decision to act comes after the motor preparations for the act (the readiness potential). This suggests that our conscious will might not be the cause of our actions, and Wegner (2002) has argued that we make inferences after the fact about whether we caused a particular action. These results could be interpreted to show that CC sets do not e-cause c-reports about consciousness because motor preparations for verbal output (for example) would precede the events that are correlated with consciousness. This problem could be resolved by measuring the relative timing of a proposed correlate of consciousness (CC1 in Figure 4.4) and the sequence of events leading to the report about consciousness, including the readiness potential (R1-R3 in Figure 4.4). If the framework presented in this book is correct, then it should be possible to find CC sets with the appropriate timing relationship. If no suitable CC sets can be found, then the framework presented in this book should be rejected as flawed. It is worth noting that Libet’s measurement of the timing of conscious events implicitly depends on a functional connection between consciousness and c-reporting behaviour—the relative timing of consciousness and action can only be measured if consciousness is functionally connected to c-reports about consciousness (in this case with a delay).

45 It is reasonably easy to see how the contents of consciousness that are c-reported could be e-caused by physical events. For example, we can tell a simple story about how light of a particular frequency could lead to the activation of spatiotemporal structures in the brain, and how learning processes could associate these with sounds, such as ‘red’ or ‘rojo’. This might eventually enable a trained brain to produce the sounds ‘I can see a red hat’ or ‘I am aware of a red hat’ when it is presented with a pattern of electromagnetic waves. Since consciousness does not appear to us as a particular thing or property in our environment and many languages do not contain the word ‘consciousness’ (Wilkes 1988b), it is not necessary to identify sensory stimuli that the physical brain could learn to associate with the sound ‘consciousness’. The concept of consciousness can be more plausibly interpreted as an abstract concept that is acquired by subjects in different ways (see Chapter 2). So it is conceivable that the scientific study of consciousness could be carried out without subjects ever using the word ‘consciousness’ in their c-reports.

46 See Footnote 15 for the distinction between structural, functional and effective connectivity. Effective connectivity can be measured using algorithms, such as transfer entropy (Schreiber 2000) or Granger causality (Granger 1969), which works on the assumption that a cause precedes and increases the predictability of the effect. However, effective connectivity does not always coincide with e-causation—for example, when a signal is connected to two areas with different delays.

47 In the real brain many areas are reciprocally connected to each other and there is a great deal of recurrent processing. This simplified diagram only shows the general flow of activity from perception to reporting.

48 Cohen and Dennett (2011) illustrate the low resolution of our peripheral vision.

49 Our ability to access high resolution information on demand contributes to our sense that we perceive the world in uniformly high resolution (O’Regan 1992).

50 This is a conservative estimate based on eye-movement driven changes and the assumption that consciousness consists of a series of discrete moments (the specious present). It is also possible that consciousness changes continuously.

51 See O’Regan (1992).

52 People can be trained to make more accurate reports about their consciousness (Lutz et al. 2002) and there has been a substantial amount of work on the use of interviews to help people describe their conscious states. In the explication interview (EI) a trained person interviews a subject about a conscious state to help them provide an accurate report (Petitmengin 2006). In descriptive event sampling (DES) the subject carries a beeper, which goes off at random several times per day. When they hear the beep the subject makes notes about their consciousness just before the beep. This is followed by an interview that is designed to help the subject to provide faithful descriptions of the sampled experiences (Hurlburt and Akhter 2006). Froese et al. (2011) discuss some of the first- and second-person methods for measuring consciousness. These techniques place a heavy reliance on memory, so it is unlikely that they can address the problems highlighted in this section.

53 Shanahan (2010) suggests how an omnipotent psychologist could measure a person’s consciousness by reversing time and carrying out different interventions.

54 Mental techniques could also be used to reset consciousness. For example, people with a high level of mental focus, possibly gained through meditation, might be capable of putting their consciousness into a particular state and maintaining this state for an extended period of time.

55 It might be possible to use what we know about the relationship between a stimulus and consciousness to make reliable inferences about a person’s state of consciousness. Suppose we knew that an awake expectant person always has a conscious experience of a red rectangle when a red rectangle is presented at the centre of their visual field. If this inference was reliable, it might not be necessary to measure their consciousness using c-reports when we expose them to a red rectangle—we could simply infer that since they are looking at a red rectangle, they must be conscious of a red rectangle. However, the limited resolution and active nature of the visual system means that a complex model will be required to map between stimuli and conscious states. Furthermore, this method of inference can only be developed by measuring consciousness using c-reports, which depends on the assumptions that have been presented in this chapter.

56 Nagel (1974, p. 449).

57 You might think that you could validate the descriptions by resetting your consciousness to the state that is being described. But then you would have to compare a remembered description with your current state of consciousness without modifying your current state of consciousness.

58 Formal descriptions of the physical world are covered in Section 5.1.

59 These problems are discussed by Chrisley (1995a) and Gamez (2006).

60 The use of XML to describe consciousness is discussed by Gamez (2006; 2008a).

61 See Balduzzi and Tononi (2009).

Table des illustrations

Légende Figure 4.1. Problem of colour inversion. a) A person teaches us the word ‘red’ by pointing to a coloured patch and making the sound ‘red’. Your colours are inverted relative to mine, so my red is your turquoise, and so on. We both learn to associate the colour that we experience with the sound ‘red’. b) We observe a severed ear on a table. The colour of the torn edge of the ear is similar to the colour that we experienced when we learnt the word ‘red’, so we both report that we are experiencing the colour red. The colours in our bubbles of experience are very different, but there is no way of detecting this in our external behaviour. Image © David Gamez, CC BY 4.0.
URL http://books.openedition.org/obp/docannexe/image/5555/img-1.jpg
Fichier image/jpeg, 244k
Légende Figure 4.2. Some of the definitions and assumptions that are required for scientific experiments on consciousness. The normally functioning adult human brain is a platinum standard system (A4), which is associated with consciousness (D4). Consciousness nomologically supervenes on the platinum standard system (A3) and all of it can be c-reported (A1, A2). Image © David Gamez, CC BY 4.0.
URL http://books.openedition.org/obp/docannexe/image/5555/img-2.jpg
Fichier image/jpeg, 132k
Légende Figure 4.3. The relationship between macro-and micro-scale e-causal events. a) A car moving at 5 m/s collides with a fat man and knocks him down. This is a macro-scale e-causal event in which the car passes energy-momentum to the man. b) The macro-scale e-causal interaction between the car and man can be reduced down to the micro-scale exchanges of energy-momentum between atoms in the car and man. c) The temperature of the car’s engine is a macro-scale property that moves at 5 m/s and collides with the man. The engine temperature exchanges a small amount of energy-momentum with the man in the form of heat, but not enough to e-cause him to fall down. Image © David Gamez, CC BY 4.0.
URL http://books.openedition.org/obp/docannexe/image/5555/img-3.jpg
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Légende Figure 4.4. Assumptions about the relationship between CC sets, consciousness and first-person reports. The labels S1, CC1, R1, etc. refer to any kind of spatiotemporal structure in the brain, such as the activation of a brain area, neural synchronization, electromagnetic waves, quantum events, and so on. They are only illustrative and not intended to correspond to particular anatomical paths or structures. An e-causal chain of sensory spatiotemporal structures, S1-S3, leads to the appearance of a spatiotemporal structure, CC1, that is functionally connected to consciousness. In this example the contents of consciousness are determined by sensory events, but in principle they could be independent of S1-S3—for example, if the subject was dreaming. CC1 is assumed to be the first stage in an e-causal chain of spatiotemporal structures, R1-R3, that lead to a verbal description of consciousness. Image © David Gamez, CC BY 4.0.47
URL http://books.openedition.org/obp/docannexe/image/5555/img-4.jpg
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