First Speaker: George Lakoff
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First Speaker: George Lakoff |
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Questions and Summaries of George Lakoff's chapters
1) The Embodied Mind chapter three from Lakoff and Johnson:
Philosophy in the Flesh
(discussed by Vanessa Gack)
Lakoff and Johnson (L&J) take issue with the Western philosophical theory
of faculty psychology--that reason is seen as separate and independent o
f what we do with our bodies. Citing evidence from cognitive science, L&J
aargue that in some cases," rational inferences can be computed by the s
ame neural architecture used in perception or bodily movement."
version I ("trivial"): conceptual structures are neural structures becaus
e they are realized neurally
version II (strong): " An embodied concept is a neural structure that is
actually part of, or makes use of, the sensory motor systems of our brai
ns so that much of conceptual inference is sensory-motor inference" (p.7
).
Some Questions:
1) What do we think of the assumptions which frame their inquiry?
a) categorization is a consequence of how we are embodied
b) categories, concepts and experience are inseparable
c) the architecture of your brain's neural networks determines what con
cepts you have and hence the kind of reasoning you can do.
d) Whenever a neural ensemble provides the same output with different i
nputs, there is neural categorization
e) a small % of categories are a consequence of conscious acts-- rather,
through experience, categories are subject to unconscious reshaping and
partial change
f) what we call concepts are neural structures that allow us to mentally
reason about them
2) What do we think of the linguistic evidence that they cite in support
of their argument?
a) color concepts
L&J say that our brains and bodies have evolved to create color out of f
our factors: 1) wavelenghts of reflected light; 2) lighting conditions; 3
) the three color cones in our retinas which absorb three wavelenghts of
light; 4) the neural cirquity conncected to the cones. Thus, color is no
t an internal representation of external reality -- but a function of the
interaction between our brains' ability to make sense out of different l
ighting conditions and surfacce reflectances. Colors are not substances
or things. Therefore: we lose the corresponence theory of truth (sign3D
external reality).
b) basic level categories ( eg chair in the middle of category hierarchy
"furniture-CHAIR-rockingchair").
The basic level is the highest level at which 1) we have mental images th
at stand for the entire category; 2) category members are regognized by p
erception of overall shape; 3) we have motor programs for interacting wi
th objects in the category; 4)most of one's knowedge is organized. L&J a
rgue that the difference between basic-level categories and non-basic lev
el categories is body-based; we interact at that level with the environme
nt; consistent with part-whole structure, this level makes sense to us .
(Note that they also apply basic-level categories to actions like swimmin
g, emotions like anger...)
c) spatial relations concepts DEPEND on the body. They "characterize wha
t spatial form is and define spatial inference" (p.23) (in front of, in b
ack of...) " They have an "image schema, a "profile; and a "trajector-la
ndmark structure."
c1 container schemas (bounded regions in space) highlight the interior
of the schema, identify the boundary of interior as landmark and the obje
ct overlapping the interior as trajector e.g. "sam is in the house," wher
e house3Dlandmark relative to Sam the trajector (note: container schemas
are cross-modal and can be applied to something we see, hear...)
c2 source-path-goal schemata have "a trajector that moves, a starting poi
nt, a goal (destination), a route from source to goal, a trajectory of mo
tion, the position of the trajector at a given time(t), the direction of
trajector at (t), and final location of trajector.
they depend on spatial logic:e.g. toward, away, through...
c3 bodily projections- we project our fronts and backs on to objects. W
hile English is relatively impoverished (using terms like in front of, be
hind...) other languages project bodily position as the primary means wit
h which to characterize spatial relations. (e.g. in Mixtec, instead of s
aying "he is on top of the hill" one says "he is located head hill."
3) What do we think of the neural modeling evidence that they cite in sup
port of their argument?
Given spatial relations concepts, concepts of bodily movement (e.g. grasp
, pull) and aspectual concepts that structure actions or events (e.g. sta
rting, completed) Reason does not appear to be separate from perception
and bodily movement. How might this work?
The Neural Theory of Language (NTL) group have been trying to make neural
models of embodied cognition-- particularly language acquisition/use, th
us linking neural computation with the forms of COMPUTATION required by l
anguage AAND thought. They have five levels of methodology (35-37)
Level 1. Cognitive Science and Cognitive Linguistics
Level 2. Neurally Reducible Conventional Computational Models
Level 3. Structured Connectionist Models
Level 4. Computational Neuroscience
Level 5. Neuroscience
The link between Level 4 and Level 5 is given by computational
neuroscience:
I'll only tersely summarize these experiments and let Lakoff do the expla
ining.
a) NTL spatial relations learning task-Regier's Model
R's model is hybrid, consisting of two parts:1) a connectionist model of
neural structures; simulating the visual system whose job is characteriz
e spatial relations & make distinctions; 2) a PDP connectionist model for
learning via back-propogation. According to L&J, this model's significan
ce is that "the fundamental CONCEPTUAL ROLES for making the right lingui
stic distinctions among the vers are PLAYED by features of the MOTOR SYST
EM.
b) NTL verbs of hand motion learning task-- Bailey
Bailey used a computerized model of the body, an assumed collection of mo
tor synergies(motor actions like pivoting the wrist, tightening a grip) a
nd Petri nets to execute the motor schemas.Bailey videoed the computerize
d body performing the hand movements, then had informants label the move
ments with verbs.Then, Bailey made a learning mechanism that would learn
the verbs from the computerized agent making the movements
Results: on the sample of 18 English verbs, the recognition rate was 78%
and the command-obeying rate 81%
c) NTL motor control and abstract aspectual reasoning task--Narayanan
In this task, Narayanan constructed a neural (mappable by known methods o
n to a neural model) theory of metaphor that used bodily movements to met
aphorically discuss international economics (eg France falls into a reces
sion). L&J argue that since the link between physical and economic domai
ns could be modeled by neural connections--this work acts as an "existenc
e proof."
4) What do we think of L&J's characterization of the relevant philosophic
al issues? (p.8-9). And, to what extent does their evidence address their
philosophical concerns?
a)categories exist independent human brains, bodies ; the relationship am
ong categories is characterized by transcendent/ universal reason. Thus h
uman reason is disembodied.
b)human concepts are the concepts of transcendent reason; categories are
fixed and objective.
c)reason is culture-free and what makes us human has nothing to do with t
he social or material world.
5) What are the implications for a theory of mind and how might this work
impact the field of cognitive science?
a) human reason is a form of animal reason-- we might learn about embodied human reason through our study of embodied animal reason ?
b) human reason can be studied in neural network models ?
c) at last, evidence of embodied cognition-- faculty psychology is dead
?
Discussion
While I felt comfortable with the strong version of L&J's argument, ["An
embodied concept is a neural structure that is actually part of, or makes
use of, the sensory motor systems of our brains so that much of concept
ual inference is sensory-motor inference" (p.7).] I was not convinced b
y the trivial version (conceptual structures are neural structures becaus
e they are realized neurally). I do not understand the idea that-- becau
se conceptual structures are realized neurally that they are neural struc
tures. Neural structures perform a certain ffunction, but do they compri
se that function?
We say, for example, that respiration is realized by the lungs-- but we d
o not say that lungs are respiration-- respiration is accomplished via th
e lungs, alveoli, diaphragm, intercostal mmuscles etc. There is plastici
ty in this system (when we can not breath through our nasal passages, we
can breath through our mouths). Neural structures also appear quite plas
tic, but I do not understand them to be interchangeable.
As a consequence of my own limited understanding, I failed to ground the
following assumptions:
c) the architecture of your brain's neural networks determines what conc
epts you have and hence the kind of reasoning you can do.
f) what we call concepts are neural structures that allow us to mentally
reason about them
This one, however, seems plausible enough:
d) Whenever a neural ensemble provides the same output with different i
nputs, there is neural categorization
And I was satisfied with their characterization of mainstream Western phi
losophy, but then again, I'm not a philosopher. Philosophers? Thus, I b
ought these assumptions:
a) categorization is a consequence of how we are embodied
b) categories, concepts and experience are inseparable
e) a small % of categories are a consequence of conscious acts-- rather,
through experience, categories are subject to unconscious reshaping and
partial change
Re: evidence
I found the linguistic evidence quite interesting and convincing-- of emb
odied reason, but not of concepts as neural structures. I found the compu
tational evidence fascinating and plausible,, but not convincing.
I still believe that there is an enormous gap between the physical brain
and the level of human concepts and language; we may need more than rese
arch methodologies already in place within cognitive science to bridge th
at gap. I, myself, am not convinced of how to link levels 1 and 2 or 1 a
nd 5
I am looking forward to tomorrow's talk and hoping that in addressing my
questions, he will convince me...
Philosophy in the Flesh
Lakoff & Johnson
Chapters 4 & 5
summary by Jeanne Milostan, Computer Science & Engineering
==========================================================
Chapter 4: Primary Metaphor and Subjective Experience
We saw in Chapter 3 that there is much evidence that, humans being
evolved creatures, reasoning (rational thought) and categorization
are inherently embodied. Chapter 4 continues the ideas, presenting
evidence and arguments for the idea that human reasoning about
subjective experiences is also embodied. Hence, we use our experience
from sensory-motor domains to make subjective judgments and
decisions within non-physical domains.
The use of sensory-motor knowledge to frame our views of abstract
domains is inherent *in the way we think about them* in addition to
the language we use to describe them. Lakoff & Johnson present
a framework for why these conceptual metaphors are so widespread:
The Integrated Theory of Primary Metaphor
A) Conflation: early in our experience sensory-motor and subjective
experiences tend to occur together and thus the concepts are formed
in conjunction. As children gain more experience, the two domains
can be distinguished, but the associations remain. I.e. More Is Up:
Levels go up, not down, as we add more.
(Recall the problem children have with conservation re: Piaget)
B) Primary Metaphor: These early associations form "primary metaphors"
from which more complex metaphors can be built.
C) Neural Theory of Metaphor: The associations made by conflation are
the result of concurrent activation in separate domains; this
simultaneous activity results in permanent neural pathways being
learned between the two areas.
(Hebbian learning on a meta-scale?)
D) Conceptual Blending: Different domains are coactivated and
connections between them can be formed, leading to both on-the-fly
and culturally conventionalized activations. This is in addition
to the associations formed during conflation, and accounts for the
conventionalization of more complex metaphors.
The rest of the chapter fleshes out each of these points in more detail
and with examples. Several points fall out of this framework:
Primary Metaphor (More Is Up) in inevitable. This is a result of
our being human and interacting with the environment. These should
also account for some of the universal concepts seen within
widely disparate cultures.
Metaphors are Cross-Domain Mappings. This chapter concentrated on
mappings from sensory-motor experience to making subjective judgments.
Can we think without metaphor? Yes, but it is difficult to do so
without conscious effort:
I was blindsided by the flu.
What I mean is the flu hit me when I wasn't looking.
But no, that's still metaphorical.
I caught the flu... wait a minute...
I became ill with the flu when I wasn't expecting it.
====================================================================
Chapter 5: The Anatomy of Metaphor
Building on the bases laid down in previous chapters (reasoning is
embodied, and primary metaphors are inevitable), chapter 5 explores
how complex metaphors are constructed and why specific metaphors can
be so pervasive within a culture.
Examining the metaphor A Purposeful Life is a Journey, Lakoff & Johnson
go into great detail about how cultural beliefs (People are supposed
to have purposes in life) combine with primary metaphors (Action Is
Motion and Purposes are Destinations) and facts (A long trip with a
series of destinations is a journey) to form pervasive metaphors:
A Purposeful Life Is A Journey
Lakoff & Johnson then spend quite some time exploring the implications
of this metaphor. Specifically, they explain how our common-sense
reasoning about the "journey" domain allows us to then reason
automatically about the "life journey" domain. They look at how
these metaphors are not just figures of speech, but reasoning tools
and bases by which we make everyday decisions (this in particular is
covered extensively in L&J's other works). They look at how these
complex metaphors, especially when conventionalized to the extent
that people hardly even realize that they are metaphors, can then be
used to construct even more complex metaphors (Love Is A Journey)
which again are used as the basis for reasoning.
As summarizer, I find that the discussion presented in Chapter 5
seems to follow from the framework laid out in Chapter 4, supported
again by the other works of the authors and their collaborators.
The main weight of the argument seems to then lie on that framework,
particularly part A (conflation) and C (Narayanan's neural theory
of metaphor, from Chapter 3). The evidence for these two points
are what I feel need to be more thoroughly explored.
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Speakers | Article Summaries | xxxxx | xxxx
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