Consciousness Explained, chapter 3

byPhilGoetz10y11th Jan 20107 comments

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A Visit to the Phenonemological Garden

This chapter categorizes and discusses mental phenomena.  It emphasizes that we don't re-draw the outer world inside our heads for a little person to look at.

1. Welcome to the phenom

"Kant distinguished "phenomena," things as they appear, from "noumena," things as they are in themselves, and during the development of the natural or physical sciences in the 19th century, the term phenomenology came to refer to the merely descriptive study of any subject matter."

["Phenomenology" seems similar to what I recently called "mere curve-fitting" in a comment exchange about gravity, as something that lets us make accurate predictions about a phenomenon, while still leaving it in the realm of metaphysics (not integrated causally into the rest of physics).]

D will use the term "phenom" to denote the (true) ontology of conscious phenomena.  He divides it into

  • sense perceptions
  • imagined perceptions
  • affect

2. Our experience of the external world

D tells an interesting fable about a philosopher who denied that the mechanical reproduction of an orchestra's sounds could be possible, due to a failure of his own imagination.  He then challenges the naive assumption that, after all the sound of all the different instruments have been translated into a stream of pulses, they get converted back into all the different orchestral sounds in the brain.  The distinctive sounds of different instruments, once thought to be unanalyzable, are due to the superposition of a number of different frequencies and amplitudes of pure tones.  This leads into the argument that we don't experience sounds in our heads - we're not going to go to the effort to break sound down into frequencies just to get it inside our heads, and then build the original waveform back up again.  Similarly, we imagine we hear word boundaries in speech; yet there are no gaps between words in the acoustic energy profile.

Vision:  We don't draw pictures in our heads and then look at them.  That would lead to an infinite regress.  Besides, it's dark in there.  Our visual perception is a conglomeration of different objects at different resolutions tagged with different visual properties.

3. Our experience of the internal world

The gist of this section seems to be that we don't imagine things by, eg., drawing pictures in our heads.  [I remember an experiment 5 or 10 years ago, in which a subject was able to literally draw a simple figure in its primary visual cortex, detected by fMRI, by imagining it.  So I'm not sure this is a meaningful distinction to make.  Imagining a scene may start at an end closer to consciousness; but it still ends up re-activating images in topographically-mapped areas.]

4. Affect

Fun is a mysterious phenomenon not yet given enough attention by philosophers.  Affect and qualia are still mysterious; but D promises (p. 65) to give a materialistic account of them.

Summary

[I agree with most of this chapter, with the caveat that a large percentage of our cortex is taken up with topology-preserving maps of our visual field, of the type D says we don't have.  I'm willing to overlook this, because I expect that a lot of the "important stuff" goes on in more rostral associational brain areas.  But in order to make this excuse for D, I have to slide a little toward the "Cartesian theater of the mind" view that D is going to spend much of the book arguing against.]

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