University Studies 15A: - PowerPoint Presentation

Slide1

University Studies 15A:Consciousness I

Philosophical Skepticismabout a Neuronal SelfSlide2

An initial pair of questions:

Are there things about yourself that you would like to change?What keeps you from changing them?

Let me suggest a theme for today’s lecture.

“No such thing as selves exist in the world; nobody ever

was

or

had

a self” Thomas Metzinger

We should be so lucky.Slide3

Let us begin with Hume’s linkage of consciousness, perception and the self (or lack of one):

For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe any thing but the perception. (David Hume, A Treatise on Human Nature)

He “never can observe any thing but the perception.” Indeed. Is that really true?Slide4

Immanuel Kant concluded that, if one reflects, one realizes that all perceptions have a frame that is not part of the things perceived:

Kant accepts Hume’s critique that we cannot find causality in the world; we infer that when event B regularly follows immediately upon action A,

A

causes

B

, but this conclusion is not really justified. Kant argues that here we have to postulate a self that orders perception through the additional category of causality that this self provides.

Kant sees a self in the form of the perception.Slide5

Let’s consider another pair of examples of perceptions:Slide6

What is that black doing in the blue sky?Slide7

It is far too simple to say that these two paintings of cornfields are Van Gogh’s perception of the fields at different times. The technical aspects reflect painterly questions of how to use the brush, paint, and color and how to organize the canvas to convey a particular sense of

both what it was like to look at a cornfield and what it was like to engage a painting as a work of art.

Still, to say that the perceptions behind the paintings were perceptions not framed most viscerally by a self is not to be looking at the paintings.

So, what is this self?

The challenge is to keep this self in mind when reading all the arabesques of argumentation in Blackmore.Slide8

In this context, let me slightly rephrase an exercise Blackmore proposes.

She wants you constantly to ask the question, “Who is conscious now?”She asks, “Can you see, hear, or feel the

experiencer

as opposed to the experienced world?” Good question.

Let me give you an example:Slide9

Did you find a self in the shifting consciousness here?

Can you propose a neuroscientific account of this self from what you have learned?Slide10

Blackmore’s framework is to consider two classes of models of the self:

1. “Ego theories:” there is a substantial, persisting self2. “Bundle theories:” the “self” is a temporary aggregation of elements

Keep this neuroscientific model in mind as we turn to Blackmore’s account

Blackmore offers the Buddhist analysis as an early “bundle theory”

In classic Vedic thought, the self,

atman

, was a part of the larger world-soul,

Brahman

. Ascetics sought to purify the self so as to return to the purity and formless totality of

Brahman

. Gautama (the Buddha) initially followed the Vedic tradition but then, in a moment of enlightenment, concluded there was no

atman

to return to

Brahman

, and with no

atman

, the self extinguished.

Instead of a permanent

atman

, the self was a condensation of five “heaps” (

skandha

: form, sensation, conception, volition, discernment) that scattered again on death. This is indeed a “bundle theory.”Slide11

Blackmore asserts, “It might seem obvious that materialist scientists should… be bundle theorists. After all, if the brain consists of millions of interconnected neurons whose activity gives rise to behaviors, memories and perceptions, then there is no need for an experiencing self as well

.” (p. 117)As well? Where is she looking for this self? What does she want it to be?

Blackmore continues, “Yet,… some scientists still try to count the number of selves in a split-brain patient, or ask whether multiple personalities are really separate selves, implying at least some components of ego theory

.” (p. 117)

However, is there a compelling reason why one could not have several competing bundles of self rather than several competing ego-selves?

Ego Theories – Bundle Theories

Let’s consider some of Blackmore’s test cases.Slide12

Example One – The Brain Transplant: what would change in your “self” if your brain ended up inside another body?

Neuropsychology describes personal space in terms of kinds of 'near-ness' to the body.Extrapersonal Space: The space that occurs outside the reach of an individual.

Peripersonal

Space

: The space within reach of any limb of an individual. Thus to be 'within-arm's length' is to be within one's

peripersonal

space.Pericutaneous

Space: The space just outside our bodies but which might be near to touching it. Visual-tactile perceptive fields overlap in processing this space so that, for example, an individual might see a feather as not touching their skin but still feel the inklings of being tickled when it hovers just above their hand.Previc further subdivides extrapersonal space into focal-extrapersonal space,

action-

extrapersonal

space, and

ambient-

extrapersonal

space. Focal-

extrapersonal

space is located in the lateral

temporo

-frontal

pathways at

the center of our vision, is

retinotopically

centered and tied to the position of our eyes, and is involved in object search and recognition.

Action-

extrapersonal

-space

is located in the medial

temporo

-frontal pathways, spans the entire space, and is head-centered and involved in orientation and locomotion in topographical space. Action-

extrapersonal

space provides the "presence" of our world. Ambient-

extrapersonal

space initially courses through the peripheral

parieto

-occipital visual pathways before joining up with vestibular and other body senses to control posture and orientation in earth-fixed/gravitational space. Numerous studies involving

peripersonal

and

extrapersonal

neglect have shown that

peripersonal

space is located dorsally in the parietal lobe whereas

extrapersonal

space is housed ventrally in the temporal lobe

. (Wikipedia)Slide13

Can you be the same “you” in a different body?

Can you be the same “you” if you lose a limb?I’m gambling that someone said “The same in all the essentials.”

What are the essentials?

Where

are the essentials?

Example Two – The

Teleporter

: Suppose a machine scanned you, sent all information about you to a different location, reassembled an identical version of you, and destroyed the original:

Would the new version be you?Slide14

Neuroscientific Models of the Self

Blackmore discusses:Ramachandran

“executive process” using the limbic system

Damasio

proto-self

(the brain stem, thalamus, and insula)

autobiographical self (cortical structures built drawing on the proto-self)

Baars

’ Global Workspace Theory

self-system (including self as observer, self as agent)

Baars

shows that consciousness can become detached from the

self-system in a variety of “

dissociative conditions”