The purpose of this meetup is twofold:
- To give a broad CONCEPTUAL overview of the major theories of consciousness. These theories can be divided in two conceptual categories with different empirical and conceptual implications.
- To ask, what do theories of consciousness purport to explain to begin with? What should they try to explain? What can they explain in principle?
First of all, it is important to note what are NOT theories of consciousness (TOC). Physicalism, dualism, and panpsychism are general metaphysical theories about the mind-body relationship, not TOCs. Functionalism and mind-body identity are specific physicalist theories which may point us to particular TOCs, but are not in themselves TOCs. This thread provides a broad overview of functionalism and mind-body identity. There are also theories about the nature of conscious content, such as representationalism, which are not TOCs. A TOC is a theory that at a minimum specifies a mechanism for why a mental event is conscious, as opposed to unconscious. TOCs can be philosophical, psychological or biological.
First, we can ask what we should be looking to explain. Several authors have suggested that we start with the common sense conception of consciousness:
It also makes sense to stay as close as possible to everyday, natural language usage for related terms. In common usage, the term “consciousness” is often synonymous with “awareness,” “conscious awareness,” and “experience.” For example, it makes no difference in most contexts to claim that I am "conscious of" what I think, "aware of" what I think, "consciously aware" of what I think, or that I can “experience” what I think. Consequently, to minimise confusion, it is important not to load these terms with added meanings that are peculiar to a given theoretical position. (Max Velmans)
Second, we should ask what aspect of consciousness does a specific theory purport to explain? As we will see, a pervasive problem in the field is that different theories simply define consciousness as whatever their theory explains. For example, Antonio Damasio has been criticized for defining consciousness as self-consciousness, and ignoring phenemonal consciousness (not surprising, as his theory purports to explain self-consciousness).
"What Was I Thinking?" by Ned Block
"How Weird Is Consciousness? Scientists may not even be asking the right questions" by Alison Gopnik
A similar criticism (ignoring phenomenal consciousness by defintion) has been levelled at the well-known Global Workspace Theory.
But as we will discuss, it is not easy to isolate phenomenal consciousness (if it exists discretely) experimentally.
The following articles survey the major theories of consciousness.
"Theories of Consciousness" by Ned Block
"Neurobiological Theories of Consciousness" by S. Kouider
"Cognitive Theories of Consciousness" by deGardelle and Kouider
It is quite apparent that given the proliferation of TOCs, many if not all will be eventually be proven wrong in significant aspects. As Kouider notes in his article, "over the last two decades, dozens of theories of the NCC have been proposed." It may seem difficult to see the forest through the trees here. But TOCs can be broadly divided into 2 categories (I will refer to visual awareness as that is best understood).
The first category could be characterized as "functional" (see my first link in this discussion for more detail). In these theories, consciousness is a ROLE. These theories are more abstract, and imply that consciousness could be substrate-neutral, (e.g., realized outside the brain) such as in computers. The best known of these theories include the global workspace theories, higher order theories, and the information integration theory. In more concrete terms, they typically identify visual awareness as occurring in the ANTERIOR parts of the brain (prefrontal and parietal). These could also be identified as more "global" than the "local" biological theories.
The second category could be characterized as "biological" (well known proponents include Christof Koch and Victor Lamme). In these theories, biology is the REALIZER of the roles consciousness plays. These theories are more "local" identifying visual awareness as occurring in POSTERIOR (occipital) areas of the brain. These have also been referred to as "first order" theories. Given that these theories are more detailed in specifying neural mechanisms, they imply mind-brain identity, as it would be hard to have consciousness in an organism without very similar neural mechanisms.
At this point, it is useful to discuss the issue of phenomenal and access consciousness. In the words of Ned Block (the originator of the idea):
Consciousness is a mongrel concept: there are a number of very different "consciousnesses." Phenomenal consciousness is experience; the phenomenally conscious aspect of a state is what it is like to be in that state. The mark of access-consciousness, by contrast, is availability for use in reasoning and rationally guiding speech and action. These concepts are often partly or totally conflated, with bad results.
Now while this distinction has been widely adopted by scientists, some believe that there is no distinction, there is only one type of consciousness. Some think that phenomenal consciousness cannot occur without access, while others think they can come apart (in particular that there can be phenomenal without access consciousness). In the preceding anterior-posterior brain distinction, access is anterior, while phenomenal consciousness could be anterior or posterior depending on your theory. These views are closely tied to which TOC one holds, and how one might interpret the results of various studies.
In practice, access is often identified with attention, although it is not completely identical. So one question would be, what is the relationship of attention to consciousness? If phenomenal consicousness cannot occur without access (attention), then it is not clear how one could really study phenomenal consicousness discretely, and some (like Dennett) will question whether such a thing even exists. Per Cohen and Dennett:
Any neurobiological theory based on an experience/function division cannot be empirically conﬁrmed or falsiﬁed and is thus outside the scope of science.
It is clear, then, that proper scientific theories of consciousness are those that specify which functions are necessary for consciousness to arise. A true scientific theory will say how functions such as attention, working memory and decision making interact and come together to form a conscious experience. Any such theory will need to have clear and testable predictions that can in principle be verified or falsified. Most importantly, such theories will not claim that consciousness is a unique brain state that occurs independently of function; instead, the focus will be placed on the functions themselves and how they interact and come together to form consciousness.
"The attentional requirements of consciousness" by Michael A. Cohen et al.
"Consciousness cannot be separated from function," by Michael A. Cohen and Daniel C. Dennett
So to see how this might play out in practice, imagine an event of visual awareness with anterior and posterior brain activation. In functional theories, it might be hypothesized that the posterior activation is unconscious content, the anterior activation is attention which is necessary for consciousness, and with both we have phenomenal consciousness. In a biological theories, it might be hypothesized that the posterior activation is phenomenal consciousness while the anterior activation is attention which is not necessary for phenomenal consciousness (remember, the biological theories state that visual awareness is posterior, so they don't want attention (anterior) to be necessary for consciousness).
We will look at one theory of consciousness, the higher order thought (HOT) theory. Why this theory? The HOT theory is a philosophical TOC which is based upon a simple commonsense concept, and as such is very easy to understand—and in fact its proponents tout its intuitive nature as one of the major strengths of the theory. Here is the basic principle of HOT, simply stated:
A subject’s mental state is conscious when the subject is aware of herself as being in that state.
In the link above, I'm only discussing the actualist higher order thought theory.
Although the HOT seems abstract, it is possible to test it empirically and some think, to prove it superior to other TOCs by empirical means.
"Empirical support for higher-order theories of conscious awareness" by Hakwan Lau and David Rosenthal
“Arbitrating philosophical theories of consciousness by cognitive neuroscience experiments”
Finally, do any of the TOCs even begin the answer the famous “hard problem” of consciousness? What might a possible answer even look like? In the paper linked above, Cohen and Dennett state that the "hard problem" is an IMPOSSIBLE problem, as phenomenal consciousness cannot be separated from function even in ideal circumstances - and thus cannot be studied by science. Here is the hard problem as stated by its originator, David Chalmers:
What makes the hard problem hard and almost unique is that it goes beyond problems about the performance of functions. To see this, note that even when we have explained the performance of all the cognitive and behavioral functions in the vicinity of experience—perceptual discrimination, categorization, internal access, verbal report—there may still remain a further unanswered question: Why is the performance of these functions accompanied by experience? http://www.iep.utm.edu/hard-con/
There are really a lot more possible links—I've tried to provide a reasonable number but even that is a lot. You don't have to do any reading though—I will try to keep things at a very conceptual level.