Susan Blackmore, Consciousness: A Very Short Introduction, Oxford U. P. 2005. Chapters 3-5. [Comments in square brackets are my own thoughts.] Ch. 3: TIME AND SPACE ^^^^^^^^^^^^^^^^^^^^^ This chapter is about the temporal relations between world events, neural events, and consciously perceived events, the role of attention, and about some theories of consciousness (again, dualist theories; "HOT" theories that say that awareness of what we are experiencing is essential for consciousness; Baars' theory; neuronal loop/assembly theories; and Dennett's multiple-drafts theory, claiming many processes can compete for attention, and we are conscious of whichever ones are most prominent at a given moment) Libet's delay (p.33-36) ^^^^^^^^^^^^^ Consciousness of a feeling (even when evoked by direct brain stimulation) comes about half a second after stimulation for touch, and about one fifth of a second after stimulation for vision . [So conscious awareness comes only after significant processing -- not surprising.] But that seems to imply that everything we see and hear happened 0.2 seconds ago, and what we feel on our bodies happened 0.5 seconds ago. [I think that's why insects manage to bite us before we can slap them -- they may have half a second before we notice, and perhaps additional time before the hand hits!] Note that reaction times as measured by pushing a button when becoming aware of a visual stimulus are significantly faster than times for becoming aware of a touch. According to Wikipedia, "Mean RT for college-age individuals is about 160 msec milliseconds to detect an auditory stimulus, and approximately 190 milliseconds to detect visual stimulus." Note that this includes a simple motor response. Perhaps conditioned reflexes are faster still, but I doubt they're faster than 100 ms. [So in sports, success depends partly on reflexes, and partly on extrapolating from what was the case 200 or so ms ago. That's why a sucker punch, if not signalled by any small posture changes or expression changes, is virtually impossible to block; and why you can't catch that dollar bill dropped suddenly between your fingers.] Why don't we realize all this? "Subjective antedating". One issue here is how we "align" visual feedback with touch feedback, so that they *seem* simultaneous, e.g., in grasping an object. Apparently Eccles, Popper, and Penrose think our capacity for fast action, despite the 1/2sec delay, indicates "mind over matter". But most others don't. Blackmore thinks the notion of an external event like a touch on the arm "reaching consciousness" encounters the hard problem. [I would suppose the processing is needed to abstract a location and category of sensation from the signal stream; that leaves the question why the abstracted information becomes conscious.] Clocks and rabbits (p.36-39) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ - retroactive consciousness (e.g., clock chimes) [This suggests to me we abstract quite a bit of information from the auditory input stream, storing it at least for a short time (a few seconds?), but don't become conscious of abstracted info till we attend to it (evidence for HOT theories?] - the cutaneous rabbit -- we reorganize the actual events somewhat. [I'm not sure why this tactile illusion challenges the "stream of consciousness". In any case, it hasn't worked for any of my classes, or my family members, yet!]] Driving unconsciously (p.40-43) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ We need little conscious attention for driving. [But I think the fact that we can't remember what specific events happened along the way may not mean we weren't paying attention at the time -- perhaps they just weren't important enough to be committed to memory! So in retrospect, it seems as if we were mentally absent. Also I think we have to distinguish between experiencing qualia, and conscious awareness *that* we are experiencing these qualia. The "redness" of the passing car that we now can't remember was perhaps no different from the "redness" we would have experienced, had we been more interested in the car; but our *awareness* of experiencing that redness may have been minimal -- so "higher-order" consciousness of the red-quale was nearly absent.] Some theorists say attention is essential to consciousness. But what directs attention? Conscious processes? See also Arien Mack and Irvin Rock, next chapter, p.62, inattentional blindness. Theories of consciousness (p.43-49) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - Eccles, Popper, & Penrose (dualism) - Penrose and Hameroff: microtubules & quantum effects - HOT theories [HOT requires a self-model; so are creatures without self-model not conscious? I think McDermott would say yes.] - Baars' global workspace theory; doesn't explain why any workspace contents are conscious, says Blackmore. [globally available abstractions" available to self-model?] - Dennett's multiple drafts theory - What was I conscious of a moment ago? [But just because the stream of consciousness leaves few traces for recall doesn't mean it didn't happen!] Ch. 4: A GRAND ILLUSION ^^^^^^^^^^^^^^^^^^^^^^^ Illusions, the role of emotion, subliminal perception, etc. All indicating a faulty intuitive conception of consciousness... "Vision is a grand illusion" - visual illusions (p.51) - the illusion that consciousness is needed for really tough problems (p.52-3) - There's much we perceive and don't realize we perceive (p.54-5) e.g., subliminal perception (word priming), intuitive assessment of people, situations - we fill in gaps: occlusion; Dennett's house of Marilyns -- fast detection of oddities gives illusion of total consciousness; Gregory & Ramachandran - filling in textures, colors, even "unreadable" letters (non-foveated) - change blindness (p. 58-60): "the richness of our visual world is an illusion" (the pedestrian & the door carriers, etc) [I disagree: we just don't record much of it; and why should we use up valuable synapses, when it's right before us?!] - there's much we're not aware of, though it's right before us; inattentional blindness (Mack & Rock) -- prominent objects missed if not attended to. [Have you seen the movie??] - "Every time we move our eyes we throw away most of the available information" [I think we don't throw away much, because we don't *record* much in the first place. Mobile robots don't (usually) store films, either.] - Levin & Simon -- only the gist is retained; (p.63) somewhat similarly, Ronald Rensink; [sounds plausible; however, MIT cognitive scientist George Alvarez has shown that (a) we do perceive the statistical structure of non- foveated regions, and (b) we do retain enough detail in LTM to be able to categorize thousands of briefly seen images, mixed with new ones, as "previously seen" or "new".] Blackmore thinks we can't find the "movie in the brain" that Crick and Damasio want to find. [But I think we might - it just doesn't get recorded; whatever parts we attend to *do* get transduced into conceptual representations in STM, but this too may be largely forgotten, i.e., not committed to LTM.] Ch. 5: THE SELF ^^^^^^^^^^^^^^ [The ancient Egyptions regarded the heart as the seat of the soul; likewise the ancient Hindus: "The Self, smaller than small, greater than great, is hidden in the heart of the creature" -- the Upanishads] The feeling of "the self" as "owner" of body and brain; [I think it's important to be aware that "having" is an ambiguous verb, and two of its main meanings are "having- as-part" and "possessing as owner". Note that if "I have a nose" is understood as "I have-as-part a nose", then "I" can perfectly well *include* my nose and other parts. It is only the "possessor" reading that leads to the idea of a possessor separate from the "possessions", such as a nose, etc. An exercise: take the first paragraph of the chapter and change all "I"s to "you"s.] Look: if someone touches me on the shoulder or on my toe, did they touch ME? Of course they did. So I'm NOT something separate from my parts! I could see how a robot, equipped with an initial "self" concept to which it ascribes its perceptions, could also arrive at a confused notion of what that "self" corresponds to in the world. After all (as in the comment on babies earlier on), it has no firm basis a priori on which to decide what parts to include as part of itself, and what parts to regard as just objects that it owns and controls? A person with prosthetic limbs might have a hard time in that respect as well.] Split brains (p.70-74) ^^^^^^^^^^^^^^^^^^^^^ - e.g., show pictures to one hemisphere, words to the other --> two selves; confabulation; Parfit claims there's neither one self nor two selves; there are just experiences, but no-one having them. [Seems silly to me. There are two selves that overlap (mostly in sharing the body, just like extreme Siamese twins). Each has a self-model.] Hypnosis, multiple personalities (dissociative disorder).(p.75-8) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [Well, why not multiple self-models? The self-modelling idea doesn't get enough attention here. We could build robots with multiple self-models, even separate knowledge bases; so why shouldn't it be possible in people? Recent example: Sassy Beyonce and Sasha; For fun: Stephen Wright: "If a person with multiple personalities threatens suicide, is that considered a hostage situation?] Theories of self (p.78-81) ^^^^^^^^^^^^^^^^^^^^^^^^^ - William James (p.79) distinguished "me" (objective) and "I" (subjective) [a rare mistake, I think.] "Thought is itself the thinker" [cute, but not too coherent, I think.] - All the theories mentioned -- Ramachandran, even Baars, Damasio -- are formulated in terms of neural activity [and I think as such fail to latch on to the idea of an internal symbol that stands for the self -- an obvious thought from an AI perspective.] Dennett (see p.81) does hint in the direction of a self-model -- "a center of narrative gravity". But language then supposedly "spins" this into an "inner self". [I think it just relies on an inner *symbol* for the self -- where that symbol simply denotes the person as a whole! The "inner self" idea (as opposed to an inner *symbol* for oneself) leads to hopeless confusion, and the conclusion that "there is no-one having these experiences"! That conclusion should trigger some sanity-alarms...]