Ned Block gave a Google talk (embedded below) that was ostensibly supposed to be about why AI approaches to cognition won’t work. However, while he does address this topic briefly, it’s toward the end and he admits he hasn’t really justified it, beyond a vague proposition that while access consciousness involves information processing, maybe phenomenal consciousness doesn’t, or is more dependent on its biological substrate, or something.
But most of the talk is devoted to a discussion about whether phenomenal consciousness is sparse or rich. Sparseness refers to the fact that if you look at a detailed picture or diagram, then after it has been removed from view, you are asked to write down what you remember from it, your recollections are going to be sparse.
We have an impression that the initial sensory experience was rich, that we took in all the detail, and that it’s only our memory of it that is sparse. However, many researchers think that the initial impression or richness is an illusion, that the initial conscious perception is far sparser than we think it is.
We can take in a complex scene and quickly get a gist of it, make a prediction based on sparse information. Which, as the history of witness trials show, can often be wrong. We see what we expect to see. We might then focus on one or two details in the scene, and then come away with the impression that we experienced the entire scene, when in reality we only experienced the broad outline of it followed by the details we focused on.
Block disagrees. He’s the philosopher who originally made the distinction between phenomenal consciousness and access consciousness. Phenomenal consciousness is raw experience, the ineffable what-it’s-like aspect of consciousness. Access consciousness is our ability to access this raw experience, to use it in reasoning, and to make self reports about it.
It’s worth noting that not everyone is convinced that this is a meaningful distinction. Philosophers like Daniel Dennett think it’s a mistaken distinction, that there is no phenomenal consciousness without access consciousness. I tend to agree with this, although from a purely subjective point of view the distinction still seems useful.
There are aspects of consciousness that seem more primal, ineffable, impossible to describe, such as the redness of red or the painfulness of pain. I personally don’t have an issue with giving a name to this category of experience, while realizing that without access consciousness, we couldn’t even have a concept of phenomenal consciousness.
Anyway, Block’s contention is that phenomenal consciousness actually is rich in detail, but that this richness is lost in access consciousness, that it’s cognition which is sparse. He provides ostensible evidence in the talk, which I personally didn’t find convincing.
For example, he cites eye tracking studies, asserting that eyes focusing on something indicates conscious awareness of what the eye is pointed toward, but this doesn’t square with what I’ve read, where a lot of eye movement is driven by the superior colliculus below the level of consciousness. And it’s worth noting that we only have high resolution reception in a small part of our retina. Our impression of a scene is built on the eye moving around, movements of which we’re generally not aware.
Block notes that a lot of his opponents do think there is richness in unconscious perceptions, but that what makes it into consciousness is sparse. He thinks the richness does make it to consciousness, but not in a way that we can remember or self report.
To a large degree, this seems to get into which definition of consciousness we’re using. His opponents appear to be using a definition of what is accessible by introspection, which in humans feels like the default definition. Block seems to be saying that there is conscious content that we don’t access, which seems a bit strange. On the other hand, we often have perceptions that we don’t remember. The question is what we can say about these ephemeral experiences if we can’t introspectively capture them.
This is a scenario where the concept of consciousness may be inviting people to argue about nothing. If we make the divide between perceptions that are available for self report versus perceptions that aren’t, both parties might be in agreement. Arguing about whether we are conscious of things we can’t introspect seems like the proverbial dilemma of whether the refrigerator light stays on when the door is closed.
Block’s talk is about an hour long. I put it at the bottom to make it optional for this post. Block comes across as very personable, someone I’d enjoy having a conversation with, but I found the talk itself to be a bit scattershot. Still, despite disagreeing with his positions, it was interesting. You might find it worth the time, and I know some of you will agree with him.
Block’s citation of his opponents also reminded me that Stanislas Dehaene, a proponent of global workspace theory, has a book on consciousness I need to read.
h/t Gregg Caruso