There is a traditional scepticism about whether the world "out there"
really is as we perceive it. A new breed of hyper-sceptics now challenges
whether we even have the perceptual experience we think we have. According
to these writers, perceptual consciousness is a kind of false consciousness.
This view grows out of the discovery of such phenomena as change blindness
and inattentional blindness, which show that we can all be quite blind
to changes taking place before our very eyes. Such radical scepticism has
acute and widespread implications for the study of perception and consciousness.
The writings collected in this volume explore these implications. The contributors
are scientists and philosophers at the forefront of this research, and
include well-known authors such as psychologists Susan Blackmore and Arien
Mack, and philosophers Andy Clark and Daniel Dennett. They have an gift
for bringing these paradoxical issues to life and sharing their excitement
with the non-specialist.
TABLE OF CONTENTS
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Contributors
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Editor’s Preface
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Alva Noë
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Is the Visual World a Grand Illusion? abstractfull
text
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Daniel C. Dennett
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How Could I Be Wrong? How Wrong Could I Be? abstract
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Susan Blackmore
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There Is No Stream of Consciousness abstract
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Bruce Bridgeman
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The Grand Illusion and Petit Illusions: Interactions of Perception and
Sensory Coding abstract
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Eric Schwitzgebel
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How Well Do We Know Our Own Conscious Experience?
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The Case of Visual Imagery abstract
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Dana H. Ballard
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Our Perception of the World Has To Be an Illusion abstract
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Temre N. Davies, Donald D. Hoffman & Antonio M. Rodriguez
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Visual Worlds: Construction Or Reconstruction? abstract
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Frank H. Durgin
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The Tinkerbell Effect: Motion Perception and Illusion abstract
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Arien Mack
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Is the Visual World a Grand Illusion? A Response abstract
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Daniel T. Levin
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Change Blindness Blindness As Visual Metacognition abstract
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Charles Siewert
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Is Visual Experience Rich Or Poor? abstract
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Jonathan Cohen
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The Grand Grand Illusion Illusion abstract
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Mark Rowlands
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Two Dogmas of Consciousness abstract
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Andy Clark
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Is Seeing All It Seems? Action, Reason and the Grand Illusion abstract
ABSTRACTS
Alva Noë
Is the Visual World a Grand Illusion? full
text
In this paper I explore a brand of scepticism about perceptual experience
that takes its start from recent work in psychology and philosophy of mind
on change blindness and related phenomena. I argue that the new scepticism
rests on a problematic phenomenology of perceptual experience. I then consider
a strengthened version of the sceptical challenge that seems to be immune
to this criticism. This strengthened sceptical challenge formulates what
I call the problem of perceptual presence. I show how this problem can
be addressed by drawing on an enactive or sensorimotor approach to perceptual
consciousness. Our experience of environmental detail consists in our access
to that detail thanks to our possession of practical knowledge of the way
in which what we do and sensory stimulation depend on each other.
Alva Noë, Department of Philosophy, University of California at Santa
Cruz, Santa Cruz, CA 95064, USA. anoe@cats.ucsc.edu
Daniel C. Dennett
How Could I Be Wrong? How Wrong Could I Be?
One of the striking, even amusing, spectacles to be enjoyed at the many
workshops and conferences on consciousness these days is the breathtaking
overconfidence with which laypeople hold forth about the nature of consciousness
— their own in particular, but everybody’s by extrapolation. Everybody’s
an expert on consciousness, it seems, and it doesn’t take any knowledge
of experimental findings to secure the home truths these people enunciate
with such conviction.
One of my goals over the years has been to shatter that complacency,
and secure the scientific study of consciousness on a proper footing. There
is no proposition about one’s own or anybody else’s conscious experience
that is immune to error, unlikely as that error might be. I have come to
suspect that refusal to accept this really quite bland denial of what would
be miraculous if true lies behind most if not all the elaboration of fantastical
doctrines about consciousness recently defended. This refusal fuels the
arguments about the conceivability of zombies, the importance of a ‘first-person’
science of consciousness, ‘intrinsic intentionality’ and various other
hastily erected roadblocks to progress in the science of consciousness.
Daniel C. Dennett, Center for Cognitive Studies, Tufts University, 520
Boston Avenue, Medford, MA 02155-5555, USA. daniel.dennett@tufts.edu
Susan Blackmore
There Is No Stream of Consciousness
What is all this? What is all this stuff around me; this stream of experiences
that I seem to be having all the time?
Throughout history there have been people who say it is all illusion.
I think they may be right. But if they are right what could this mean?
If you just say ‘It’s all an illusion’ this gets you nowhere — except that
a whole lot of other questions appear. Why should we all be victims of
an illusion instead of seeing things the way they really are? What sort
of illusion is it anyway? Why is it like that and not some other way? Is
it possible to see through the illusion? And if so what happens next.
These are difficult questions, but if the stream of consciousness is
an illusion, we should be trying to answer them rather than more conventional
questions about consciousness. I shall explore these questions though I
cannot claim that I will answer them. In doing so I shall rely on two methods.
First, there are the methods of science, based on theorising and hypothesis
testing — on doing experiments to find out how the world works. Second,
there is disciplined observation — watching experience as it happens to
find out how it really seems. This sounds odd. You might say that your
own experience is infallible — that if you say it is like this for you
then no one can prove you wrong. I only suggest you look a bit more carefully.
Perhaps then it won’t seem quite the way you thought it did before. I suggest
that both these methods are helpful for penetrating the illusion — if illusion
it is.
Susan Blackmore, c/o Imprint Academic, PO Box 1, Thorverton, Devon, UK.
sjb_ac@hotmail.com
Bruce Bridgeman
The Grand Illusion and Petit Illusions: Interactions of Perception and
Sensory Coding
The Grand Illusion, the experience of a rich phenomenal visual world supported
by a poor internal representation of that world, is echoed by petit illusions
of the same sort. We can be aware of several aspects of an object or pattern,
even when they are inconsistent with one another, because different neurological
mechanisms code the various aspects separately. They are bound not by an
internal linkage, but by the structure of the world itself. Illusions exploit
this principle by introducing inconsistencies into normally consistent
patterns of stimulation.
Bruce Bridgeman, Department of Psychology, University of California at
Santa Cruz, Santa Cruz, CA 95064, USA. bruceb@cats.ucsc.edu
Andy Clark
Is Seeing All It Seems? Action, Reason and the Grand Illusion
We seem, or so it seems to some theorists, to experience a rich stream
of highly detailed information concerning an extensive part of our current
visual surroundings. But this appearance, it has been suggested, is in
some way illusory. Our brains do not command richly detailed internal models
of the current scene. Our seeings, it seems, are not all that they seem.
This, then, is the Grand Illusion. We think we see much more than we actually
do. In this paper I shall (briefly) rehearse the empirical evidence for
this rather startling claim, and then critically examine a variety of responses.
One especially interesting response is a development of the so-called ‘skill
theory’, according to which there is no illusion after all. Instead, so
the theory goes, we establish the required visual contact with our world
by an ongoing process of active exploration, in which the world acts as
a kind of reliable, interrogable, external memory (Noë et al., 2000;
Noë, 2001). The most fully worked-out versions of this response (Noë
and O’Regan, 2000; O’Regan and Noë, 2001)) tend, however, to tie the
contents of conscious visual experience rather too tightly to quite low-level
features of this ongoing sensorimotor engagement. This (I shall argue)
undervalues the crucial links between perceptual experience, reason and
intentional action, and opens the door to a problem that I will call ‘sensorimotor
chauvinism’: the premature welding of experiential contents to very specific
details of our embodiment and sensory apparatus. Drawing on the dual visual
systems hypothesis of Milner and Goodale (1995), I sketch an alternative
version of the skill theory, in which the relation between conscious visual
experience and the low-level details of sensori- motor engagement is indirect
and non-constitutive. The hope is thus to embrace the genuine insights
of the skill theory response, while depicting conscious visual experience
as most tightly geared to knowing and reasoning about our world.
Andy Clark, Cognitive Sciences Program, Indiana University, Bloomington,
IA 4705, USA. andy@indiana.edu
Dana H. Ballard
Our Perception of the World Has To Be an Illusion
Our seamless perception of the world depends very much on the slow time
scales used by conscious perception. Time scales longer than one second
are needed to assemble conscious experience. At time scales shorter than
one second, this seamlessness quickly deteriorates. Numerous experiments
reveal the fragmentary nature of the visual information used to construct
visual experience. Models of how the brain manages these fragments use
the construct of a routine, which is a task-specific fragment of a sensory-motor
program. This paper provides an overview of some of the experiments that
test these models. Its aim is to show how the structures that they elucidate
constrain the understanding of conscious perception.
Dana H. Ballard, Department of Computer Science, University of Rochester,
Rochester, NY 14627, USA. dana@cs.rochester.edu
Jonathan Cohen
The Grand Grand Illusion Illusion
This paper considers a number of ways of understanding the hypothesis that
change blindness and inattentional blindness reveal a grand illusion about
visual perception. It argues that the most prominent readings of this hypothesis
in the literature are untenable. It concludes that, while these results
have much to teach us about perception, the only illusion they can be said
to uncover is a modest and familiar one.
Jonathan Cohen, Department of Philosophy, University of California at San
Diego, 9500 Gilman Drive, La Jolla, CA 92093-0119, USA. joncohen@aardvaak.ucsd.edu
Frank H. Durgin
The Tinkerbell Effect: Motion Perception and Illusion
A new motion illusion is discussed in relation to the idea of vision as
a Grand Illusion. An experiment shows that this ‘Tinkerbell effect’ is
a good example of a visual illusion supported by low-level stimulus information,
but resulting from integration principles probably necessary for normal
perception.
Frank H. Durgin, Department of Psychology, Swarthmore College, 500 College
Avenue, Swarthmore, PA 19081, USA. fdurgin1@swarthmore.edu
Temre N. Davies, Donald D. Hoffman and Antonio M.
Rodriguez
Visual Worlds: Construction Or Reconstruction?
Psychophysical studies of change blindness indicate that, at any instant,
human observers are aware of detail in few parts of the visual field. Such
results suggest, to some theorists, that human vision reconstructs only
a few portions of the visual scene and that, to bridge the resulting representational
gaps, it often lets physical objects serve as their own short-term memory.
We propose that human vision reconstructs no portion of the visual scene,
and that it never lets physical objects serve as their own short-term memory.
Temre N. Davies, Department of Cognitive Sciences, University of California
at Irvine, Irvine, CA 92697, USA. daviest@uci.edu
Donald D. Hoffman, Department of Cognitive Sciences, University of California
at Irvine, Irvine, CA 92697, USA. dhoffman@orion.oac.uci.edu
Antonio M. Rodriguez, Department of Cognitive Sciences, University of California
at Irvine, Irvine, CA 92697, USA. tonyr@uci.edu
Daniel T. Levin
Change Blindness Blindness As Visual Metacognition
Many experiments have demonstrated that people fail to detect seemingly
large visual changes in their environment. Despite these failures, most
people confidently predict that they would see changes that are actually
almost impossible to see. Therefore, in at least some situations visual
experience is demonstrably not what people think it is. This paper describes
a line of research suggesting that overconfidence about change detection
reflects a deeper metacognitive error (which we refer to as ‘change blindness
blindness’, or CBB) founded on beliefs about attention and the role of
meaning as a support for a coherent perceptual experience. Accordingly,
CBB does not occur in all situations (subjects can, indeed, make accurate
predictions about change detection in some circumstances), while the scope
of the phenomenon remains broad enough to suggest more than a misunderstanding
of a small niche of visual experience. I finish by arguing that despite
the very small amount of research on visual metacognition, these beliefs
are critical to understand.
Daniel Levin, Dept of Psychology, PO Box 5190, Kent State University, Kent,
OH 44242-0001, USA. dlevin@kent.edu
Arien Mack
Is the Visual World a Grand Illusion? A Response
The question of whether the visual world is a grand illusion is addressed
and answered negatively. The question only arises because of the recent
work on Inattentional Blindness (IB), Change Blindness (CB) and the Attentional
Blink (AB) which establishes that attention is necessary for perception.
It is argued that IB occurs only when attention is narrowly focussed and
not when attention is more broadly distributed, which is the more typical
attentional state. Under conditions of distributed attention we are likely
to have a fuller, if less detailed, impression of the visual scene, which
may be why we are so surprised by demonstrations of IB, AB and CB. It is
also argued that the question about the possible illusory quality of our
perceptual world cannot be avoided by denying that inattention causes blindness
and asserting instead that it causes amnesia. This argument is grounded
on the similarity between these phenomena and visual neglect and by evidence
that priming by the unseen stimuli occurs in each case indicating that
the stimuli to which we are functionally blind are processed and represented
in implicit memory. The adaptive utility of this information is discussed.
Arien Mack, Psychology Department, New School for Social Research, 65 Fifth
Avenue, New York City, NY 10003, USA. mackarie@newschool.edu
Mark Rowlands
Two Dogmas of Consciousness
Most recent discussions of phenomenal consciousness are predicated on two
deeply entrenched assumptions. The first is objectualism, the claim that
what it is like to undergo an experience is something of which we are or
can be aware in the having of that experience. The second is internalism,
the claim that what it is like to undergo an experience is constituted
by states, events and processes that are located inside the skins of experiencing
subjects. This paper argues that both assumptions should be rejected. What
it is like to undergo an experience is not an object of consciousness but
something that exists in the directing of consciousness towards (non-phenomenal)
objects. What it is like to undergo an experience is not something of which
we are aware, but something in virtue of which we are aware. And there
is little reason for supposing that the directing of consciousness towards
its objects is something that occurs exclusively inside the skins of experiencing
subjects. On the contrary, directing of consciousness towards its objects
is often extended, involving acts of worldly probing and exploration.
Mark Rowlands, Department of Philosophy, University College Cork, Cork,
Ireland. mrowlands@philosophy.ucc.ie
Eric Schwitzgebel
How Well Do We Know Our Own Conscious Experience? The Case of Visual Imagery
Philosophers tend to assume that we have excellent knowledge of our own
current conscious experience or ‘phenomenology’. I argue that our knowledge
of one aspect of our experience, the experience of visual imagery, is actually
rather poor. Precedent for this position is found among the introspective
psychologists of the late nineteenth and early twentieth centuries. Two
main arguments are advanced toward the conclusion that our knowledge of
our own imagery is poor. First, the reader is asked to form a visual image,
and it is expected that answering questions about certain basic features
of that experience will be difficult. If so, it seems reasonable to suppose
that people could be mistaken about those basic features of their own imagery.
Second, it is observed that although people give widely variable reports
about their own experiences of visual imagery, differences in report do
not systematically correlate with differences on tests of skills that psychologists
have often supposed to require visual imagery, such as mental rotation,
visual creativity, and visual memory.
Eric Schwitzgebel, Department of Philosophy, University of California at
Riverside, Riverside, CA 92521- 0201, USA. eschwitz@citrus.ucr.edu
Charles Siewert
Is Visual Experience Rich Or Poor?
I will argue that, once certain crucial distinctions are acknowledged,
and the issues interpreted in their light, we will have reason to reject
‘grand illusion’ interpretations of change and inattentional blindness
research. Further, as a result of this critique, we are led to question
the assumption sometimes made that our visual experiences are only as rich
as our internal visual representations (i.e., descriptions or images formed
in our heads) are detailed. My conclusions thus provide additional support
for some important aspects of the Noë–Pessoa– Thompson perspective
mentioned earlier.
Charles Siewert, Department of Philosophy, University of Miami, PO Box
248054, Coral Gables, FL 33124, USA. csiewert@miami.edu
