Agenda Pomona College ֠ Consciousness LCS 11: Cognitive Science ֠ Family resemblances ֠ GQ 2.2 Consciousness ֠ Readiness potential ֠ GQ 2.3 due Sun, 9PM Jesse A. Harris ֠ Reading • Cunningham, 2000, pp. 189-205 February 20, 2013 • Searle, 1990 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 1 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 2 What does it mean to be conscious? Avoiding the issue, part 1 Turing’s approach What criteria can we give when trying to determine whether Let’s avoid philosophizing about this someone or something is conscious? question and instead focus on behavior that we associate with 1. Human? intelligence. Something (a machine) 2. Have a central nervous system? possesses thought just in case we 3. Possess certain physical brain regions? can’t distinguish it from something 4. Engage in some form of communication? else that we intuit does have thought. Trades criteria for behavior. If it walks like a duck . . . Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 3 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 4
Avoiding the issue, part 2 Consciousness, towards a definition Goal Solipsism Give necessary and sufficient properties for consciousness. Consciousness and other mental states are private. Private states Necessary: A is necessary for B, iff (if and only if) B cannot must be experienced to be known. be true unless A is also true. Since I can’t experience your mental Sufficient: A is sufficient for B, iff (if and only if) by knowing states for you, I can’t know whether that A is true, you also know that B is true. or not you have them. Advantage Assumes that conscious states are Gives you complete overlap between A and B. transparent to the holder. Could all be brains in a vat Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 5 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 6 Necessary and sufficient conditions – examples Necessary and sufficient conditions – examples Example 1 Example 2 A = breathing; B = being a living human A = Being (evenly) divisible by 4; B = Being an even number Necessary: No – 2 is an even number, but is not evenly Necessary: Yes – you can’t be a living human without divisible by 2. breathing (including assisted breathing) Sufficient: Yes – if you know that a number is evenly Sufficient: No – since there are other things, like dogs, that divisible by 4, then it must also be even. breathe but are not humans. Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 7 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 8
Necessary and sufficient conditions – examples 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. Example 3 Physicalism A = Being an unmarried male; B = Being a bachelor What matters is matter! Necessary: Yes Behaviorism Sufficient: Yes Who needs mind when you’ve got behavior! Functionalism Mind is what mind does! Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 9 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 10 Consciousness as one or many? Family resemblances A game The grand assumption We all have the intuition that we Previous accounts assume the old (and venerable) idea that understand the notion of a “game” – there is a single, unified thing that we can identify as chess, checkers, squash, basketball, “consciousness”. tennis, dungeons & dragons, ... A challenge Define a game Many concepts cannot be reduced to a single property or condition or even a list of properties or conditions. But now try to define the concept of game that covers all instances ...It’s harder than you’d think! Ludwig Wittgenstein (1889– 1951) Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 11 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 12
Family resemblances GQ 2.2, group discussions Commonalities Members of category share features Do you think that consciousness constitutes one phenomenon or or properties in common, but there many phenomena, in Cunningham’s sense (pp. 64-69)? Rather than need not be a single (necessary and simply stating your opinion, take a concrete example from any of the sufficient) feature shared by each. reading from this class so far and use that example in your argument. You can even chose an example that goes against your Open question intuition! Does this help us in determine what Group leaders: Stephen, Daniel, Adele, Sam, Sarah, Nico, Noah, Alex, consciousness and mental states are? Ryan What are some of the properties or qualities that are involved in consciousness? Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 13 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 14 Investigating consciousness scientifically Investigating consciousness scientifically Electrical field As neurons fire, electrically charged ions are transported. When enough Electroencephalography (EEG) neurons fire in a group, this creates a Recording activity of electrical field change detectable outside the scalp. around the scalp with a cap containing multiple electrodes EEG waves measuring the slight oscillations. The EEG signal from each electrode is filtered to reduce noise and then averaged together, timelocked to some event. Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 15 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 16
Benjamin Libet and co. Readiness potential Voluntary movement is preceded by a readiness potential , a Main question signature movement in the electromagnetic fi eld around the scalp. When does the decision or intention to act appear with respect to the Typically precedes actual movement by about 1 second when actual movement? performed at will. 1. Before movement? Brain begins volitional process well before voluntary act was 2. Concurrently? performed. 3. After? Benjamin Libet (1916–2007) Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 17 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 18 Benjamin Libet and co. Experiment 1. In an oscilloscope clock, a spots of 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 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 19
Note: RP greater when subjects keep track of desire to move (grey line) Mysteries Assessment Open question If the readiness potential appears before the conscious urge to Open question act, then do we have free will ? Or is conscious desire just post Are you happy with this? Does it imply some form of hoc awareness of an event? determinism? Veto power Open question Libet proposed that conscious processes do not initiate volutional processes, but instead may veto or cancel those How else might we interpret these fi ndings? processes. Fits with the fi nding that no RP occurs before involuntary acts, as a Tourette’s outburst. Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 23 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 24
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 Jesse A. Harris: LCS 11: Cognitive Science, Consciousness 25
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