LCS 11: Cognitive Science Family resemblances GQ 2.2 Consciousness - - PowerPoint PPT Presentation

Pomona College

LCS 11: Cognitive Science

Consciousness

Jesse A. Harris February 20, 2013

Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 1

Agenda

֠ Consciousness ֠ Family resemblances ֠ GQ 2.2 ֠ Readiness potential ֠ GQ 2.3 due Sun, 9PM ֠ Reading

• Cunningham, 2000, pp. 189-205
• Searle, 1990

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What does it mean to be conscious?

What criteria can we give when trying to determine whether someone or something is conscious?

• 1. Human?
• 2. Have a central nervous system?
• 3. Possess certain physical brain regions?
• 4. Engage in some form of communication?

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Avoiding the issue, part 1

Turing’s approach

Let’s avoid philosophizing about this question and instead focus on behavior that we associate with

• intelligence. Something (a machine)

possesses thought just in case we can’t distinguish it from something else that we intuit does have thought. Trades criteria for behavior.

If it walks like a duck . . .

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Avoiding the issue, part 2

Solipsism

Consciousness and other mental states are private. Private states must be experienced to be known. Since I can’t experience your mental states for you, I can’t know whether

• r not you have them.

Assumes that conscious states are transparent to the holder.

Could all be brains in a vat

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Consciousness, towards a definition

Goal

Give necessary and sufficient properties for consciousness. Necessary: A is necessary for B, iff (if and only if) B cannot be true unless A is also true. Sufficient: A is sufficient for B, iff (if and only if) by knowing that A is true, you also know that B is true.

Advantage

Gives you complete overlap between A and B.

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Necessary and sufficient conditions – examples

Example 1

A = breathing; B = being a living human Necessary: Yes – you can’t be a living human without breathing (including assisted breathing) Sufficient: No – since there are other things, like dogs, that breathe but are not humans.

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Necessary and sufficient conditions – examples

Example 2

A = Being (evenly) divisible by 4; B = Being an even number Necessary: No – 2 is an even number, but is not evenly divisible by 2. Sufficient: Yes – if you know that a number is evenly divisible by 4, then it must also be even.

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Necessary and sufficient conditions – examples

Example 3

A = Being an unmarried male; B = Being a bachelor Necessary: Yes Sufficient: Yes

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How about our theories?

For each proposal, list plausible necessary and sufficient conditions for mental contents. You may need to make a few distinctions before being able to answer the question.

Physicalism

What matters is matter!

Behaviorism

Who needs mind when you’ve got behavior!

Functionalism

Mind is what mind does!

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Consciousness as one or many?

The grand assumption

Previous accounts assume the old (and venerable) idea that there is a single, unified thing that we can identify as “consciousness”.

A challenge

Many concepts cannot be reduced to a single property or condition or even a list of properties or conditions.

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Family resemblances

A game

We all have the intuition that we understand the notion of a “game” – chess, checkers, squash, basketball, tennis, dungeons & dragons, ...

Define a game

But now try to define the concept of game that covers all instances ...It’s harder than you’d think! Ludwig Wittgenstein (1889– 1951)

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Family resemblances

Commonalities

Members of category share features

• r properties in common, but there

need not be a single (necessary and sufficient) feature shared by each.

Open question

Does this help us in determine what consciousness and mental states are? What are some of the properties or qualities that are involved in consciousness?

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GQ 2.2, group discussions

Do you think that consciousness constitutes one phenomenon or many phenomena, in Cunningham’s sense (pp. 64-69)? Rather than simply stating your opinion, take a concrete example from any of the reading from this class so far and use that example in your

• argument. You can even chose an example that goes against your

intuition! Group leaders: Stephen, Daniel, Adele, Sam, Sarah, Nico, Noah, Alex, Ryan

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Investigating consciousness scientifically

Electroencephalography (EEG)

Recording activity of electrical field around the scalp with a cap containing multiple electrodes measuring the slight oscillations.

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Investigating consciousness scientifically

Electrical field

As neurons fire, electrically charged ions are transported. When enough neurons fire in a group, this creates a change detectable outside the scalp.

EEG waves

The EEG signal from each electrode is filtered to reduce noise and then averaged together, timelocked to some event.

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Readiness potential

Voluntary movement is preceded by a readiness potential, a signature movement in the electromagnetic field around the scalp. Typically precedes actual movement by about 1 second when performed at will. Brain begins volitional process well before voluntary act was performed.

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Benjamin Libet and co.

Main question

When does the decision or intention to act appear with respect to the actual movement?

• 1. Before movement?
• 2. Concurrently?
• 3. After?

Benjamin Libet (1916–2007)

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Benjamin Libet and co.

Experiment

• 1. In an oscilloscope clock, a spots
• f light revolves around the

screen every 2.56 seconds.

• 2. Subject to move at any time

desired

• 3. Asked to note when became

aware of conscious desire to act

• 4. Compare Awareness time to RP

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Note: RP greater when subjects keep track of desire to move (grey line)

Mysteries

Open question

If the readiness potential appears before the conscious urge to act, then do we have free will? Or is conscious desire just post hoc awareness of an event?

Veto power

Libet proposed that conscious processes do not initiate volutional processes, but instead may veto or cancel those

• processes. Fits with the finding that no RP occurs before

involuntary acts, as a Tourette’s outburst.

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Assessment

Open question

Are you happy with this? Does it imply some form of determinism?

Open question

How else might we interpret these findings?

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Next time

Monday

֠ GQ 2.2 due Sun by 9PM GQ will be posted on the web by Friday ֠ Reading

• Cunningham, 2000, pp. 189-205
• Searle, 1990

Next week

֠ Writing response 1 returned ֠ Discussion of projects

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