Transcript PPT - Consciousness

Is the brain any closer
to the mind than the
environment?
Where and when
does my
consciousness
takes place?
Riccardo Manzotti
12 March 2014,
Sinha Lab
1
Some assumptions to start from
Consciousness is real
If it is real it has to be physical
(so much the worse for the
hard problem)
If it is physical it must share
the essential features of
physical entities
If consciousness is physical,
I want to know
• Where does it happen?
• When does it happen?
• What is it?
• How does it happen?
• What are the necessary and sufficient
conditions for it to happen?
3
4
Illusions
• perceiving things that exists differently from what they allegedly are
(argument from illusion, I)
• S experiences O as F, but O is not F
5
Therefore, I am inclined to think that
these tastes, smells, colors, etc., with
regard to the object in which they
appear to reside, are nothing more than
mere names, and exist only in the
sensitive body; insomuch that when the
living creature is removed all these
qualities are carried off and annihilated;
But I do not believe that there exists
anything in external bodies for exciting
tastes, smells, and sounds, but size, shape,
quantity, and motion, swift or slow; and if
ears, tongues, and noses were removed, I
am of opinion that shape, quantity, and
motion would remain, but there would be
an end of smells, tastes, and sounds,
which, abstractedly from the living
creature, I take to be mere words.
Galileo, The Assayer, 1623
object
(physics)
nature
subject
(physiology)
9
Luigi Galvani (Bologna, 9 settembre 1737 – Bologna, 4 dicembre 1798)
11
12
Lehar, S. [2003] Gestalt Isomorphism and the Primacy of Subjective
Conscious Experience: A Gestalt Bubble Model, Behavioral and Brain
Sciences, 26, 375-444.
Cristof Koch, The Quest for Consciousness,
Roberts & Company, 2004
A common confusion between
neural and physical
•
The dreaming brain shows us that sensory input and motor output are
not necessary for producing a fully realized phenomenal level of
organization. The dreaming brain creates the phenomenal level in an
isolated form, and in that sense provides us with insights into the
processes that are sufficient for producing the phenomenal level.
(Revonsuo 2000: 58)
•
“If there is one thing that scientists are reasonably sure of, it is that
brain activity is both necessary and sufficient for biological sentience”
(Koch 2004, p. 9).
•
if you are a physicalist of any stripe, as most of us are, you would likely
believe in the local supervenience of qualia – that is, qualia are
supervenient on the internal physical/biological states of the subject.
(Kim 1995, p. 160)
(Crick and Koch 1998; Llinàs 2001; Zeki 2003; Koch 2004; 2010; Tononi
2004; 2010; Lamme 2006; Kim 1995; Revonsuo, 2000; 2010, etc.).
The localization of conscious
experience
•
Langsjo, J. W. et al H. (2012). Returning from oblivion: imaging the neural
core of consciousness. Journal of Neuroscience, 32(14), 4935–4943.
•
Tononi, G., & Koch, C. (2008). The neural correlates of consciousness:
an update. Annals of the New York Academy of Sciences, 1124, 239–61.
•
Rees, G., Kreiman, G., & Koch, C. (2002). Neural Correlates of
Consciousness in Humans. Nature Reviews Neuroscience, 3(4), 261–270.
•
Zeki, S. (2001). Localization and Globalization in Conscious Vision.
Annual Review of Neuroscience, 24, 57–86.
•
Kitazawa, S. (2002). Where conscious sensation takes place.
Consciousness and Cognition, 11(3), 475–7.
•
Portas, C. M., et al. (2000). How does the brain sustain a visual
percept? Philosophical Transactions of the Royal Society of London B,
16
267(January), 845–850.
Cristoph Koch, The Quest for Consciousness,
Roberts & Company, 2004
How it is that a state of
consciousness comes about
as a result of irritating
nervous tissue, is just as
unaccountable as the
appearance of Djin when
Aladdin rubbed his lamp.
Thomas Huxley, 1866
An uncomfortable question
(in neuroscience)
• If the physical world is devoid of mental
qualities,
• How is it possible that the brain, which is a
piece of the world, had any mental quality?
19
A comparison
Temperature Average
speed of
molecules
Pressure
Yes
Yes
State change Yes
Yes
Conduction
Yes
Yes
Convection
Yes
Yes
Temporal
properties
Yes
Yes
Succesful
A comparison
Experience
Neural activity
Quality
Yes
No
Representing
the external
world
Yes
Yes/No
Unity
Yes
No
Perspectivalness
Yes
No
How does it score?
YET … Is the brain really sufficient for
conscious experience?
• Born blind people lack visual phenomenal
experiences
• Subjects’ experience seems to reqire direct
acquaintance with actual physical
phenomenon
• If there are no pheomenal qualities in the
external world why they should occur in the
brain?
?
The Myth of pure internal
mental content
• No evidence of it
• With all the conceivable diseases and
malfunctions, why don’t we have
reports of unexpected mental content
• Why are hallucinations so
conservative?
23
The myth of the pristine
phenomenal content
•
•
•
•
•
•
•
Forbidden colors, Billock (2010)
Reddish Green, Crane & Piantanida (1983)
Phantom limb in congenitally limbless subjects, Brugger et al (2000),
Melzack et al. (1997)
Supersaturated red, Hurvich (1981)
Color imagery in congenitally blind, Esref Armagan, Kennedy (2006)
Chromatic Synaesthesia in congenitally blind, Wager (1999)
Phantom penises in pre-operated female-to-male transsexuals,
Ramachandran & McGeoch (2008)
Where to look for
consciousness?
• I need to look for something that
has the properties of
consciousness without assuming
anything (like internalism does).
• What are the properties of
consciousness?
– Unity
The basic idea: the
rainbow
First step
Skogarfos, Iceland
To exist is to be represented and to be represented is to take place
The generalized
rainbow:
Representation as
identity
Second step
World
Physical
processes
Peripheral
“neural”
processes
CNS
“neural” processes
“neural” processes?
Information?
Meaning?
Phenomenal content?
The process as a whole contains the
object we have an experience of
time
What are objects?
u
u
n
u
u
u
u
n
u
u
n
n
n
n
n
u
u
n
u
u
u
u
n
u
u
30 8 17 25 28
18 15 11 9 14
31 3 5 23 29
10 22 19 4 20
16 8 7 6 12
Object = physical process
The classic objection
• This may be true for direct and
veridical percetion (maybe) … but
what about all those cases in which
there doesn’t seem to be any object
to be perceived? Like
– Not veridical perception
– Illusions
– Hallucinations
Third step The mirror and the caleidoscope:
All perception is direct perception!
Let’s debunk the myth of
indirect perception …
• I claim that it is possible that all
cases of phenomenal experience
usually related to indirect
perception may be reconceived as
cases of direct perception once
their external target is located.
Helmotz’s like color space (retina based)
R
G
B
61
Herring’s like color space (early processing based)
R vs G
Y vs B
W vs B
62
Herring
Like
Space
This is empirically
wrong!
(Hurvich)
RGB
space
=
63
likewise
=
=
64
• Red stimulus  cyanish afterimage
65
66
67
68
69
70
71
72
73
object perception
74
overlayed model of afterimages
75
afterimages: a way to see more by
substracting something else
f
Furthermore, afterimages as a case of direct
and veridical perception of external colors
76
Illusions
• perceiving things that exists differently from what they allegedly are
(argument from illusion, I)
• S experiences O as F, but O is not F
77
The flying pink elephant
Mirror and others
analogies
Kaleidoscope model of
hallucinations and dreams
The flying pink elephant
time
now
The “funnel” view of the brain
Direct perception
Memory
Dream
P
R3
R2
N
O I S
Light?
Bits?
R1
R1
R1
Traditional model of percepti
space
O
I
I
P
S N
now
time
Alternative view
The Spread Mind
x
O=P
N
t
x
t
•
•
•
•
•
•
•
•
Bottom line – tentative
pros
No longer appearance vs. reality
Unified ontology physical world – subjective experience
Hard problem of consciousness set aside
Identity between subjective experience and physical
experience
Revised notion of macrophysical objects
Ontological foundation for existential/physical now
Representation problem settled in identity terms
Predictability