Suppose you’re at a jazz concert. You notice horn-like noises, along with what seems to be a visual image of someone working the slider of a bright, brassy trombone. Here are two ways of thinking about this episode, assuming that you are perceiving accurately rather than hallucinating.
❁ You are directly perceiving someone playing a trombone.
❁ You are inwardly experiencing sounds and sights, which leads you to infer that someone is playing a trombone. This inference happens with such lightening speed that you don’t even notice it. All you notice is that you’re seeing and hearing a trombone solo.
On the second interpretation, we do not directly perceive the world. Instead we are aware of an inner simulation of worldly objects, and we treat this simulation as if it were real.
Phenomena such as horn-sounds and the visual image of a musician have sometimes been called sense data. Some advocates of “indirect realism” claim that we know sense data directly, and this indirectly informs us about real events in the outside world.
In the early Twentieth Century many indirect realists thought sense data were non-physical, following in the footsteps of Seventeenth Century philosopher René Descartes. But this “Cartesian” view has been rejected by those who believe that everything is made of matter. To them, speaking of immaterial substances such as sense-data sounds like mumbo-jumbo. So indirect realism has acquired a rather bad odor these days, especially if it even hints at sense data. An influential paper by Gilbert Harman disparaged the “notorious sense datum theory.” (http://plato.stanford.edu/entries/sense-data/). Uriah Kriegel reports that indirect realism “is widely regarded as bankrupt …” (Subjective Consciousness, p. 225).
Many scholars have now abandoned the “internalist” idea that experiences are inside of us. Marching under the banner of externalism, they contend that conscious experiences only inform us about things in the outside world. Michael Tye, for example, has famously proclaimed that “[sensory] phenomenology ain’t in the head.” (Ten Problems of Consciousness, p. 151.) He concludes a recent book by calling scholars to the barricades:
“For the thoroughly modern materialist, the thesis of phenomenal internalism … should be ‘committed to the flames.’ Only then will all vestiges of Cartesianism be eliminated from the materialist worldview.”(Consciousness Revisited, p. 199)
In asking whether consciousness could be a brain event, we are actually dealing with two questions:
❁ Why don’t conscious experiences seem like brain events?
❁ Why does it seem as if they are definitely not brain events?
Obviously conscious experiences do not grant us admission to the nonstop party our neurons are having in our skulls. Nevertheless, experiences could consist of brain activity even though we cannot introspect them as brain activity. This may be no more mysterious than looking at a river or a geranium without detecting the atoms of which they are composed. In this blog I will mostly focus on the more difficult question – why sensory experiences seem to almost shout that they are not brain events.
When someone enjoys the sights and sounds of a concert, the smell and taste of pecan pie, or the tingle of a caress, are these experiences mental events? Are they the direct detection of objects in the world? Or both? Or neither? What do you think – and why?
Roger Christan Schriner
To subscribe to this blog, click the “Follow” link which is typically located on the upper left.
The Mystery of Consciousness, and Why It Matters 