Consciousness and apparent motion: Paradox resolved

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Running head: APPARENT MOTION: PARADOX RESOLVED

Consciousness and apparent motion: Paradox resolved

Aleksandar Aksentijevic

University of Roehampton, London, UK

Short biography:

Aleksandar Aksentijevic is a Senior Lecturer in Psychology at the University of Roehampton,

London. His main area of expertise is experimental psychology and his areas of interest

include perception, especially auditory perception, perceptual organization, complexity, time

perception and consciousness.

Author note:

Aleksandar Aksentijevic, Department of Psychology, University of Roehampton;

Correspondence concerning this article should be addressed to Aleksandar Aksentijevic,

Department of Psychology, University of Roehampton, Whitelands College, Holybourne

Avenue, London, SW154JD UK. E-mail: [email protected]. Tel: ++44 208

392 5756. Fax: ++44 208 392 3527.

Theory and Psychology (December 2015). Advance online publication.

DOI: 10.1177/0959354315621401

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APPARENT MOTION: PARADOX RESOLVED

Abstract

A perceptual phenomenon called apparent motion has been described as a paradox that

challenges the notions of causality and temporal order. While the illusion has generated a

passionate and often highly technical debate about the relationship between subjective

experience and its objective description, no accounts so far have examined the possibility that

the source of the paradox lies not in the mysterious workings of the brain but in the

inadequacy of the reductionist explanation. Here, I suggest that the paradox is created by the

deep estrangement between subjective and objective perspectives which has created two

separate and conflicted worldviews. The illusion itself reflects a veridical perceptual

experience, while its analytical explanation fails because it lacks the very qualities it is trying

to account for. Although the proposed solution is controversial, it offers a simple and

potentially far-reaching explanation for a long-standing problem in psychology and

consciousness research.

Keywords: Apparent motion; color phi; consciousness delay; Stalinesque;

Orwellian; precognition

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Consciousness and apparent motion: Paradox resolved

The Problem

“All too rarely do I find colleagues who will assent to the proposition (which I find

irresistible) that the very ground-rules of science, its concern only for public knowledge,

preclude its finding an explanation for my consciousness, the one phenomenon of which I am

absolutely certain. (Pippard, 1992, p. 29)”

The discovery of discrepancies between subjective perception and the ostensibly real

physical phenomena has been one of the leitmotifs of consciousness research. Such

discrepancies are most often found in perceptual illusions—situations in which stimuli

produce perceptions that are incompatible with their objective descriptions. From the outset,

psychologists have been interested in illusions and for good reasons (Fechner, 1860). First,

illusions are somewhat mysterious in the sense that there are no easy explanations as to why

they should be occurring. Second, they seem to offer the promise of a deeper understanding

of perception and cognition through the use of controlled experimentation.

One important family of perceptual illusions concerns the so-called apparent motion

illusions. Apparent motion is created by means of discrete events which, when arranged

appropriately in space and time, give the appearance of movement that is not present in the

original (static) stimuli. First reported by one of the founders of Gestalt psychology Max

Wertheimer (1912), apparent motion has been researched intensively by a number of

psychologists (see Kolers, 1972). Apparent motion phenomena are generally divided into

four categories: Alpha—expansion and contraction caused by sequential presentation in the

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same location, of two objects of different size; Beta—movement is perceived between two

distinct, sequentially presented objects; Gamma—expansion/contraction caused by sequential

presentation, in the same location, of two objects of different luminance; Delta—motion in

the direction opposite to the stimulus sequence (the second light needs to be much brighter

than the first). The Beta phenomenon comprises three temporal stages. When lights are

presented simultaneously or with a very small lag (roughly under 50 ms for a visual angle of

few degrees), they are perceived as distinct (simultaneity). When the lag exceeds about 200

ms, the perception is of a regular sequence (succession). Between these extremes lies the

region of apparent motion within which one light is perceived as moving from left to right

and back. Original research (Korte, 1915) indicated that in order to maintain smooth motion,

increase in the distance between stimuli should be accompanied by an increase in the inter-

stimulus interval (coupling; Korte’s third law of motion). This was challenged by subsequent

studies (e.g. Burt & Sperling, 1981), which found that increase in spatial distance required a

decrease in temporal distance and vice versa (trade-off). The contradiction was resolved by

Ephstein & Kubovy (2007). While Korte’s law obtains at higher speeds (high ratios of spatial

and temporal distance), the trade-off is observed at lower, more commonly encountered

speeds.

Apparent motion has been studied in many contexts and under varied experimental

conditions. A particular form of the effect named the Colour phi phenomenon (Kolers & von

Grünau, 1976) has been widely discussed in the consciousness literature because it vividly

exposes the temporal paradox1. Assume a red-coloured light is flashed for approximately 150

milliseconds (ms). After a 50-ms interval, a green-coloured light, placed to the right of the

first light flashes for the same amount of time. From this description it appears that an

observer should perceive two differently coloured lights flashing sequentially—or at least

movement without the premature change in colour. While the former can be achieved by

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increasing the time interval between the lights, under optimal motion conditions the

appearance is of a light trace moving continuously from left to right and changing colour

abruptly mid-way. When both shape and colour are varied together, a smooth change in shape

is still accompanied by an abrupt change in colour at the centre of the display.

The paradox of apparent motion can be stated as follows: How is it possible to

perceive motion from stimulus A to stimulus B before the onset of the latter? In the example

of Colour phi, the question is how can we observe the second colour before the onset of the

second stimulus (Goodman, 1978)? What makes apparent motion unique is the involvement

of time which is assumed to have a special ontological status (Phillips, 2014). While

puzzling, spatial illusions and distortions can at least be described in terms of geometrical

transformations (e.g. non-Euclidean geometry; Watson, 1978) and/or neural processes (lateral

inhibition, excitation and masking; Eagleman, 2001). By contrast, apparent motion presents a

direct challenge to the notions of causality and temporal order. The philosophical

implications of the paradox are serious. In order to explain it, one must acknowledge a

fundamental disagreement between two descriptions of the phenomenon. This in turn opens

up a wide explanatory gap which is made worse by the lack of understanding of the

relationship between perception and consciousness. The assumption of simultaneity of

perception and consciousness appears to break down and the two have to be treated as

separate entities2.

Dennett (1991) proposed two interpretations for the paradox—Stalinesque and

Orvellian (see Akins, 1996 for a detailed analysis; Dennett & Kinsbourne, 1992). According

to the former3, the perception of the two discrete events is veridical. It is the post-processing

that occurs afterwards that somehow revises the perceptual input, generates the illusion and

presents it to consciousness. Since there is a delay between perception and conscious

registration, both stimuli have been processed and the motion signal encoded by the time the

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scene reaches consciousness. One example of the Stalinesque account is Tye’s (2003)

backward-looking model according to which, both events are perceived and processed before

being presented to consciousness in a compressed form to create a momentary experience

within a “specious” present4. This somewhat mysterious process ensures that the delay

between the perception and conscious experience is cancelled out and the assumption of

temporal order is maintained (see also Dainton, 2010).

By contrast, on the Orwellian scenario, the brain’s intervention takes place in

memory. Veridical representations of the stimulus (a sequence of stationary light flashes) is

encoded and stored in memory but the same form of perceptual tampering hypothesized

above changes the original perceptual representation. This distorted representation is stored in

memory erasing the original record of the event. One example of the Orwellian revision is

Grush’s (2007) account of the cutaneous rabbit illusion (Geldard and Sherrick 1972) which

has the same postdictive character as the apparent motion phenomenon5.

To summarise, according to the Stalinesque account, observers perceive, and

according to the Orwellian, remember the illusion after a brief delay (of the order of hundreds

of milliseconds), during which the brain supposedly engages in a series of operations which,

for unknown reasons, change the veridical percept into an illusory one. The notion of

backward “reconstruction” or postdiction (Eagleman & Sejnowski, 2000) is not a new one. In

the introduction to his review of apparent motion literature, Kolers (1972) discussed Zeno’s

paradoxes of motion thus: “One interpretation of Zeno is that the perception of motion is

based not on the current sensory information, but on memory for position and time; hence on

comparison, guess or inference. This interpretation alleges that what our visual system

actually detects are objects in different locations at different times; noting the disparity, we

create a sense of motion to resolve it. Perception of objects, memory of their position, and

delusion are therefore the main components, according to this theory, of our perception of

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motion. (p. 1).” This idea underpins the classical physicalist view according to which

perception of motion is caused not by an object undergoing motion, but by the limitation of

the mind which is incapable of processing the infinity of discrete spatial positions as slices of

reality. According to this view (e.g. Helmholtz, 1855), the mind fails to keep up with the

veridical perceptual processing and consequently creates solutions which in the final analysis

do not correspond with reality as defined by science. The question of why a static

interpretation should be considered veridical given the facts of experience is left unanswered.

Kolers stated that the discovery of apparent motion by the German physiologist Exner (1875)

appeared to put paid to the notion of memory interference; successive events occur so rapidly

and the perception of motion is so immediate that memory cannot be implicated in the

process. Rather, in opposition to Helmholtz, Exner suggested that motion was a basic element

of perception and cognition.

It is worth noting that in over a century of research there has been little progress in

understanding perceptual illusions, especially the family of apparent motion phenomena. A

number of theories have been put forward (see Arstila, 2015) and while differing in

perspective and emphasis, they all face an unavoidable (and as yet unresolved) problem. In

keeping with consciousness research, attempts at explaining the apparent motion paradox

have only led to more questions. While this does not necessarily imply the futility of the

quest, it does bring forth the question similar to that posed by some philosophers in the

context of physics, namely, is there a point at which the enquiry is likely to reach an end? I

propose that if not the end, then the end of the beginning might be reached not by a careful

scientific examination of the relationship between the subjective and objective accounts, or

by probing ever smaller chunks of matter using sophisticated technology, but by addressing

the question that eludes most of the current theories, namely, why should the brain indulge in

falsifying/modifying a veridical percept? What compels the brain to warp what is a simple

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physical event (two lights blinking in succession) into a mysterious causality-defying

paradox? Further, if the brain indeed does this, why is it that the experimenter remains

unaffected? For if they are subject to the cerebral subterfuge, how are they able to detect it in

another person?

Irrespective of the hypothetical cause of apparent motion, each theory must explain

the fundamental disagreement between the objective description (stationary lights flashing in

succession) and the subjective perception of continuous motion. Apart from exceptions that

challenge the veracity of subjective reports, no theory seems to disagree on the need for some

form of retrospective inference, filling in, reconstruction or completion on the part of the

brain. The only point of contention is the precise mechanism responsible for this

legerdemain. Most postdictive accounts of apparent motion (as well as theories of

consciousness) contain at least one of the following: a) a delay between perception and

conscious awareness and/or b) temporal disparity between the two. The former implies two

commensurate if misaligned temporal frameworks running in parallel whereas the latter

posits a fundamental disagreement between the two temporal metrics.

The idea of a temporal delay between sensory registration and consciousness has

been prominent in psychology and neuroscience (Eagleman & Sejnowski, 2007; Libet,

Wright & Gleason, 1982). Although superficially, the presence of a brief delay does not seem

to upset the common temporal order, reflection shows that that this is not so, for if the

observer experiences a delay between stimulus presentation and consciousness, what places

the experimenter at a privileged vantage point from which they are able to detect it? If

delayed consciousness is a universal property of minds, the experimenter’s mind should be

subject to it and consequently unable to detect the delay in another individual. Alternatively,

the idea creates infinite regress where everyone’s consciousness is delayed as soon as they

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exchange the role of experimenter for that of a subject. No appeal to precise experimentation

or sophisticated mathematical analysis can side-step this problem.

What about temporal disparity so reminiscent of the relativistic Twin paradox? The

idea here is that at least temporarily the temporal metrics of the experimenter and the subject

are substantively different. For example, 500 ms on the experimenter’s clock is experienced

as an instant by the subject. Different solutions have been suggested—from the warping of

the mental time line or multiple drafts (Dennett & Kinsbourne, 1992) and time markers

(Grush, 2004), to the contraction of an extended interval into a brief moment (Tye, 2003),

different processing speeds for location and motion in the brain (Arstila, 2015) and quantum

entanglement (Hameroff & Penrose, 2014). Perhaps the most enduring has been Libet’s (e.g.

Libet, Wright, Feinstein & Pearl, 1979) “backward referral” hypothesis according to which

consciousness backdates its records of events which are initially registered subconsciously.

The apparent paradox of backward causation (Churchland, 1981) generated a number of

interpretations—from refutation (Pockett, 2002) to evidence for non-material mind (Eccles,

1985). Yet the same logic applies—if the observer’s cognition operates under a “different

clock” even for an instant, what special quality enables the experimenter to observe the

mismatch in someone else’s mind? One possibility is that motion perception is subject to a

form of relativistic contraction of space-time, underpinned by a non-Euclidean geometry.

The study of spatial perception (Fernandez & Farell, 2009; Luneburg, 1947) Gestalt

grouping phenomena (Arnheim, 1960) and optical illusions (Watson, 1978) suggests that

Euclidean geometry cannot adequately describe the dynamic interplay between elements of a

perceptual scene (Aksentijevic, Elliott & Barber, 2001)6. Thus, describing spatial

relationships (global or local) within the framework of a non-Euclidean geometry could

provide a better description of visual experience. While they require more complex

mathematics, non-Euclidean geometries can offer a better fit between theory and data. The

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question arises as to why this should not be possible in the case of apparent motion. Although

in vision, introducing non-Euclidean space involves computational complications, it

complements and refines the existing linear models. In other words, visual grouping does not

challenge the tenets of Newtonian physics concerning the relationship between time and

space. Introducing non-linearity to explain apparent motion would involve contraction in

space-time similar to that described by Einstein (1916/2001). A mathematical model of

apparent motion by Caelli, Hoffman and Lindman (1978) proposed a relativity-like Lorenzian

space-time contraction of the experimental space-time to account for the inability of cortical

firing to keep up with the speed of stimulus presentation. In what is essentially a neural

Stalinesque model, the authors suggested that the non-linearity of apparent motion should be

described by a positive-curvature elliptic geometry. Similarly, an approximation of Lorenzian

contraction has been invoked to explain the cutaneous rabbit illusion (Goldreich & Tong,

2013). While both studies evoke a special-relativity-like framework to account for the

temporal-order paradox, neither takes the crucial step, namely, treating the experimenter’s

spatio-temporal metric as different from that of the observer. This of course would be

necessary to explain why the observer’s time disagrees with that of the experimenter (and

presumably other observers as well). The idea stretches the boundaries of credibility and even

if it were to be successfully implemented, it would still have to explain which of the two

reference frames was privileged and why.

Apparent motion represents a particularly vivid example of a lack of isomorphism

between the objective, scientific worldview and its subjective counterpart because in addition

to the mystery of non-existent motion it presents us with the puzzle of an event being

perceived before it occurs. Since we cannot deny the reality of our perception, a rational

explanation must involve some form of post-hoc reconciliation between its content and the

objective description. Understandably perhaps, no theory so far has considered the simplest

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and most obvious possibility, namely, that at the bottom of it all there is no mystery—that the

paradox of precognition reflects reality and that the experimental setup (and accompanying

line of reasoning) used to elicit it, are somehow in error. I say “understandably” because the

scientific paradigm offers the promise of a steady, fruitful progress. Starting from a set of

observations and through abstract elaboration, reality is dissected into apparently more and

more fundamental mechanisms and units. This form of reductionist description of the world

frees the mind from having to consider inconvenient irregularities. In order to be successful,

to move forward, a reductionist epistemology must appear self-contained and self-sufficient,

that is, a closed sui generis system of knowledge which at least formally is independent of

anything outside of its remit. It is this process of deliberate and presumably necessary

isolation from a broader context that gives science its power. It also underpins the supposition

that the scientific description of subjective experience is in some sense true. Arguably, as

noted by Pippard above, it also robs science of ability to explain first-person phenomena.

Let us examine this on the example of apparent motion. Wertheimer (1912) who

conducted the first systematic investigation and proposed the first theory of apparent motion,

doubted that the sensory atomism or “elementarism” of von Ehrenfels, Wundt and Titchener

according to which perception and cognition were built from a set of interacting or

“intermixing” fundamental sensations, could answer important questions about perception.

This insight led him towards a new and highly influential approach to psychology, namely,

Gestalt. The importance of Gestalt approach to the study of perception cannot be

overestimated. It was the first (and most successful) modern attempt to highlight the

importance of relationships between elements for perception. Wertheimer was right to doubt

elementarism. What escaped his attention was that the perceptual and cognitive processes

that were responsible for creating the experimental apparatus were exactly the same as those

perceiving the illusion. In other words, there is no reason to believe that the scientific

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framework responsible for arriving at the objective description of the phenomenon (two

stationary lights flashing in succession) was in any way different from or superior to, the

subjective perception which it was attempting to study. Gradual and insidious separation and

alienation of the two perspectives led to a situation in which subjective perception (which

ultimately gave rise to the very experimental setup Wertheimer was using) assumed the

mantle of objectivity and became its own investigator and judge. What appears to me as a

trace of light moving from left to right and changing colour mid-way must appear so to

Wertheimer too. Yet, he possesses an ostensibly superior grasp of the situation and knows

(without perceiving) that the two lights are separated because he did not approach the

problem from perception but from the analytical description of the experiment.

Under the weight of accumulated scientific knowledge and technological progress, the

experimental setup was taken as the objective benchmark against which phenomenology was

to be judged. Yet, the eyes (and more importantly, the brain) that perceive a travelling light

smudge are the same as those that have created the stimulus presentation and measuring

apparatus (rulers and clocks) used to investigate the illusion. How is it that these same eyes

do not see the illusion while designing the experiment? If they did, how would they know

that the lights were really separate? If they did, they would not have discovered the static

nature of the display. What caused the same mind to come to view the world in two such

mutually contradictory ways?

The solution

Although interesting in itself, apparent motion together with other temporal illusions

reveals something important about the relationship between subjective experience and its

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scientific explanation. Apparent motion does not represent a pathway to understanding how

the brain creates consciousness. Rather, it sheds light on the chasm that exists between the

two ways of knowing which has led to a great deal of conceptual confusion in consciousness

research. The problem was stated succinctly and beautifully by Democritus (Fragment 125, in

Dahlin, 2001): “According to common speech, there are colours, sweets, bitters; in reality

however only atoms and emptiness. The senses speak to the understanding: ‘Poor

understanding, from us you took the pieces of evidence and with them you want to throw us

down? This down throwing will be your fall.’” (emphasis mine).

Commonly, only the first sentence is quoted in physics textbooks. Viewed in

isolation, it is supposed to demonstrate the sophistication of the great pre-Socratic

philosopher, whose insight chimes in well with modern science. However, read in its entirety,

Democritus’s statement reveals a deeper truth. Rather than an affirmation of the superiority of

atomism, it can be seen as a melancholy realization that an unhealthy split between

experience and abstraction was under way, as well as a warning issued to the

“understanding”. There is no way of knowing if Democritus truly meant what he was saying

or whether he was being ironic given that his words run counter to his philosophy which saw

true knowledge as that achieved by means of intellect. Either way, the statement highlights

one of the most pressing problems in epistemology and philosophy of science. My

interpretation of Democritus’s words agrees with Dahlin’s: Increasingly emboldened by its

triumphs, understanding forgot its perceptual roots and turned on its progenitor. It started to

view subjective experience as unreliable and fallible, constantly seeking ways to improve and

ultimately explain it. Moving away from its origins, it accumulated power to the point of

becoming the ultimate arbiter of reality which was now described in terms of abstract

equations and invisible forces. Subjective experience was ignored or even denigrated. Like a

parvenu ashamed of their humble roots, abstract thought has projected its weaknesses and

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limitations back onto subjective perception (and ultimately consciousness) while refusing to

question its own limitations or its indebtedness to experience. It has constructed theories and

metaphors which ultimately justify its triumph. The experienced dynamic interplay of natural

phenomena which evades mathematical description is treated as an inconvenience which

obscures the truth—the universe as a void populated by particles, which on careful inspection

are not even particles but probability waves or abstract 10-dimensional strings oscillating at

the speed of light—or quantum foam. It appears that Democritus was aware of the point

which tends to escape many modern thinkers. Abstraction might bring many advantages but it

must also involve loss of information and ultimately, meaning. There is something

paradoxical in the realisation that a search for deepest meaning must result in the loss of

meaning.

The disparity between the subjective and objective domains could be ignored for as

long as the apparatus of science was directed towards ever more remote phenomena well

outside human experience. The problem escalated the moment the mind became the central

target of enquiry. Classical psychophysics established lawful relationships between physical

and mental quantities. However, knowing that measures used in arriving at these originate in

subjective experience, one can ask precisely at what point did these same measures become

“objective” and fit to assess subjective perception and cognition (from which they emerged)?

Taken further, this line of reasoning suggests that psychophysical laws do not reflect the truth

about the mind but describe its relationship with the Euclidean linear metric which itself

represents the result of a long-term cleaving of (non-linear) perception and (linearized)

measurement.

However, the tension between the first- and third-person perspectives is laid bare in

the study of consciousness and more specifically studies of temporal order. It does not come

as a surprise that today there are several theories of temporal order illusions7 and very little

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consensus on what and why causes these illusions. After a century of effort by scientists and

philosophers, we are no closer to understanding why two lights flashing sequentially produce

an illusion of motion that challenges causality and the complexity of proposed explanations

appears to be increasing. The reason is that researchers have been seeking the answer in ever

smaller and more remote realms—from behaviour, brain hemispheres and regions, neural

modules, assemblies and networks to individual neurons and sub-neuronal structures all the

way to quantum fields. While requiring increasingly more abstract mathematics and more

computational power in order to relate the data back to the original macroscopic observation,

this kind of strategy cannot answer the obvious question of how consciousness, which

enables us to perceive, think, feel and create science, can be studied by an approach that

denies it special status and treats it as an independent phenomenon, detached from everything

including the conscious thoughts and actions of the scientist. Even if this were possible, how

could it be achieved by methods which deliberately seek to disavow and “throw down” their

subjective origins8?

How does analytical dissection of experience create paradoxes? In the case of

apparent motion, the principal culprit is discretisation of time (and space) which was

contemplated as early as Zeno’s time (Glazebrook, 2001). Subjective consciousness perceives

time as continuous9. The need to represent time as a sequence of discrete intervals has little to

do with objective truth and everything to do with the need to capture the fluid, ever-changing

experiential reality within a static framework accessible to the limited cognitive grasp of the

analyst. Decomposing motion into static frames or equations “freezes” the analogue,

constantly changing phenomenon and preserves it in a form that permits further analysis and

elaboration. At the same time the act of discretisation deprives the resulting description of the

dynamic essence of movement. Even if movement is reconstituted by a careful manipulation

of static stimuli, this tells us nothing about why the stimuli should be causing the motion or

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how subjective perception is related to them—beyond the fact that motion is experienced.

The correspondence between the two descriptions of the world has been lost, perhaps

irretrievably.

The scientific study of consciousness is about providing static descriptions and

models for phenomena that are inherently dynamic. Even this statement is potentially circular

in the sense that the dynamic nature of perception and cognition can only be detected against

a static background of a derivative scientific description. The subjective perception of motion

eludes science in part because it contains information that cannot be captured by static mental

and mathematical models. No equation can reconstruct the phenomenal essence of motion

because it itself lacks that which it describes. While this is not obvious in the case of simple

forms of real motion, it becomes fully evident in the case of apparent motion where the static

description clearly fails to capture the quality of the phenomenal experience.

The resolution of the paradox lies in understanding and acknowledging the

epistemological and methodological consequences of the gradual historical separation of the

first- and third-person perspectives10

. Over time, the crucial importance of subjective

experience for the development of science (and mathematics) was gradually airbrushed out of

the history of science in a manner one could perhaps label “Orwellian”. Increasing reliance

on sophisticated apparatus and mathematical models pushed perception into the background

to the point of becoming a poor cousin of science. Perception did not fight back. It accepted

its subservient status and allowed abstract theorising and technological prowess to dominate

the discourse. By the time Exner and Wertheimer began studying apparent motion, there was

no way of “rewinding the film” and restoring the unity of subjective experience and scientific

explanation. Fortunately, the unintended pun is appropriate here given that this was the time

of the first flowering of cinema—the new art form based entirely on apparent motion (e.g.

Steinman, Pizlo & Pizlo, 2000; but see Hoerl, 2012). While the ability of film technology to

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reconstruct motion from static images hints at magic, this does imply that the integrated

experience of motion should be viewed as a flawed representation of a static reality (as

proposed by Helmholtz, 1855, and cinematographic models of perception; Dainton, 2010).

In common with other perceptual illusions, apparent motion seemed like a new and

exciting avenue of psychological research. It is not surprising therefore that original

researchers did not consider the possibility that the illusion did not lie in the percept but in the

analytical mode of reasoning which disassembles experience into simple components and

then attempts to reassemble it Humpty Dumpty-like. 103 years after Wertheimer’s seminal

investigation, perhaps the time has come to reassert the importance of subjective experience

which gave Gestalt psychology its enduring appeal. There are no mysterious mechanisms that

erase the veridical perceptual image only to replace it with a false memory of the event.

Perception is not tampering with sensation in order to fulfil some hidden agenda. There are

no covert processes and complex interactions that create temporal mirages or take the

observer outside the common space-time reference frame. Instead, there is the reality of

experience which precedes analysis and is superior to it in terms of abundance and quality of

information. Paradoxes and distortions arise because the description of the world offered by

the analytical mode of enquiry is quarantined from its origins and treated as the sole standard

of truth. Once the artificial barrier between experience and scientific knowledge is removed,

paradoxes disappear, the apparent motion effect is properly seen as a primary datum of

experience and the objective stationary-lights explanation as a simplified description that

lacks the wherewithal to reconstruct the percept. The key point is that this debility is self-

imposed. A static, linear description of the world was created in order to overcome the

impermanence and unpredictability of real experience which it was now supposed to study.

What the static experimental setup (and the accompanying intellectual apparatus) gives the

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scientist in terms of controllability of the problem space and precision, it takes away in terms

of ability to explain the richness of subjective experience.

Given that a great deal of scientific effort has been devoted to improving the precision

of measurement relative to unaided perceptual judgment, it is not surprising that

consciousness appears fuzzy, imprecise and even paradoxical when subjected to the rigour of

a physical experiment. It is equally unsurprising that the precise physical description of the

apparent motion experiment does not accord with perceptual experience. Rather than asking

why consciousness refuses to agree with the physical description of the phenomenon, we

should ask why it is that the physical description does not behave in accordance with the

perceptual experience. While, as demonstrated here, attempts at answering the first question

trigger paradoxes, the answer to the second one is straightforward—if unappealing.

Conscious perception is the beginning and end of science. If we did not implicitly accept the

validity of our perception at the very beginning, scientific progress would be impossible. We

must treat perception as veridical in order to record and describe different phenomena such as

regularities in nature. This requirement becomes even more important when it comes to the

two pillars of science, namely, systematic observation and construction of a measurement

system. Doubting perceptual experience from the start would rob science of its claim to

objectivity and reduce it to just one of a number of competing accounts of reality. Science is

based on the conviction that our experience of patterns and regularities in nature corresponds

in some way to the truth about the world. Yet, as Wertheimer and his colleagues

demonstrated so forcefully, it is the mind that seeks out patterns and regularities in order to

cope with the complexity of the environment. It follows that the discovery of troubling

discrepancies between the subjective and objective descriptions of certain phenomena such as

the apparent motion illusion brings into question the foundations of science. The dilemma is

as follows: Either conscious perception is untrustworthy in which case the validity of science

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must be in doubt (because science itself is based on subjective experience), or the

discrepancy must be due to the divorce between science and its subjective origins. Since the

first option is unpalatable, the second one seems unavoidable.

What are the consequences of such a conclusion? If the analytical framework of

enquiry is flawed vis-à-vis consciousness, then reductionist/materialist theories must by

definition be limited in their capacity to solve the hard problem (Chalmers, 1995). The move

away from direct experience is always accompanied by information loss. The increase in

precision and clarity at a lower level of explanation is bought at a cost. The rich, dynamic,

contextual information is deliberately discarded in favour of austere abstract generalisation.

As the subjective and objective modes of knowledge drifted apart throughout history

(Castillejo, 1982), this fact was either ignored or forgotten. If explaining apparent motion has

proved virtually impossible, producing a successful scientific theory of consciousness must

be that much harder. The “cause” or “source” of consciousness is unlikely to be found in

some miraculous property of action potentials or neural networks. Nor can the ineffable

conscious experience be created ex-nihilo through emergence of complex properties from an

inert (in the sense of intentionality) substrate blindly obeying physical laws. In all cases, the

explanans is too denuded of the qualities characterising the explanandum.

In conclusion, I agree with Dennett and Kinsbourne (1992) that the temporal paradox

exemplified by apparent motion is important—not because it tells us something substantive

about how the brain works but because it exposes a serious epistemological problem at the

heart of consciousness research. Paradoxes studied by psychologists do not reflect a

conspiracy by the brain aimed at depriving us of reality but a generally ignored

disengagement and alienation of subjective and objective domains that has been taking place

for at least several centuries. Although this separation does affect natural science it is when

the scientific apparatus is turned on consciousness that a deeper paradox is revealed.

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Scientific method which has done everything to purge itself from the vagueness and

uncertainty of subjective experience from which it originates is used to explain that to which

it is opposed in principle. Furthermore, and despite all methodological refinements, scientific

enquiry originates and ends in subjective experience. Without implicit belief in the

veridicality of perception, humans would never have undertaken the journey of exploration of

the world around them. Consequently, if perception and cognition are flawed, science must

be flawed too. The only way to avoid this meta-paradox is to realise that temporal illusions

do not reflect some peculiarity of perception but the inability of the objective description to

capture the quality of subjective experience. They are a testament to a long-term civilizational

process that has secured the triumph of logic and science while creating a deep

epistemological rupture. Perhaps, a better understanding of consciousness cannot be gained

without understanding how and why this rupture occurred.

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1 “Colour phi” is a misnomer. Wertheimer (1912) described phi as “pure” motion effect

which is perceived in the absence of an object being seen to change its position. The

phenomenon should properly be called “colour beta” (but see Hoerl, 2012).

2 A similar paradox involving monochromatic lights was described by Uttal (2008; p. 75).

3 The Stalinesque model is named after 1930s show trials in the USSR, at which false

evidence was produced to incriminate the accused. The Orwellian model owes its name to

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Orwell’s account of a totalitarian state’s ministry which constantly updates the past to suit its

purposes by replacing old records with new ones.

4 Some authors (“extentionalists”) disagree with the notion of an instantaneous present. For

example, Dainton (2008) suggests that the experienced present lasts approximately half a

second.

5 When a series of 15 tactile pulses is delivered in three stages (5 at the wrist, then 5 at 10 cm

higher up the arm and finally another 5 at 20 cm up the arm), rather than perceiving three sets

of spatially distinct groups of pulses, participants reported a series of spatially and temporally

equally distributed individual pulses travelling from the wrist towards the elbow. Grush

claimed that the sensation of travelling pulses was due to the fact that the participant’s

memory overwrote the initial memory trace and replaced it with the more recent one.

6 Non-Euclidean distance relationships have also been found in other areas such as similarity

judgments (e.g. Tversky, 1977).

7 Related to this, there are over a dozen competing theories of consciousness (Katz, 2013).

8 Here, a good example is the common reference to consciousness as an epiphenomenon of

brain activity.

9 Equally, one can talk about spatialization of time which was criticised by Bergson (e.g.

1910).

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10

The problems with the Cartesian dualism vis-à-vis psychology were noted and critiqued by

Husserl (1954). Husserl was very much aware of the schism between science and subjectivity

which he claimed was responsible for the “crisis” of “European humanity” (Feest, 2012).

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Consciousness and apparent motion: Paradox resolved

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