I have been unable to find a good video lecture that provides an overview of the field of Philosophy of Consciousness. The best source I know of was written by David Chalmers and published in 2003, titled
Consciousness and its Place in Nature
Unfortunately for our purposes, the paper is rather long and fairly technical, so I will give a brief summary here. I would encourage you to read the discussion above if you have the time and patience.
There are a wide array of people who have studied the problem of consciousness from the standpoint of philosophy, and many of them have credentials in both philosophy and psychology. Neuroscience and neurobiology are not particularly relevant here as they are more concerned with how the physical structures in brains work than they are concerned with what it is like to be that brain, so we will focus on the philosophical aspects. Principle philosophers engaged in this question include Daniel Dennett, John Searle, David Chalmers, Ned Block, Thomas Nagel, and we could also throw in some comments by Sam Harris, and even, going back in history, David Hume. In particular, there are videos by Dennett, Searle, and Chalmers available on youtube that provide various perspectives on the nature of consciousness. The problem with them is that each one has a rather narrow focus, trying to present their own particular view of the problem and their own particular approach to it without exposing what others have said on the subject and what criticisms arise with their approach.
Philosophies of consciousness fall into four or five main categories.
Eliminativism. Eliminativists include Daniel Dennett and Paul and Patricia Churchland. The main argument is that there is really no such thing as consciousness. Consciousness is treated as an illusion, and dismissed as “folk psychology;” that is, a belief shared by many if not most people, and yet unsupported by factual, scientific investigation. In this approach to understanding the mind, all the work that needs to be done can be done by neurobiology and those aspects of psychology that study overt behavior. Objective analysis of evidence is the primary method of eliminativism, and it is unconcerned with subjective, personal accounts of unverifiable phenomena.
Eliminativism has not had wide success. It is popular with people who share a materialistic view of the nature of the world. It has the advantage that it dispenses with all forms of spiritualism and “the ghost in the machine.” According to the eliminativists, there is no ghost, and there is nothing going on that is not visible to an objective, external observer. One suspects the main reason why some philosophers take up this view is to support the work of neuroscience, the projects of artificial intelligence, and to avoid untidy and distracting arguments with people who think these scientific projects miss the point or lack important epistemology. This is not to say that eliminativists are not sincere. Some certainly are. Dennett’s perspective on the matter (to the extent that I understand it) is that the electrochemical, neural activity in brains makes symbolic representations of feelings, emotions, and thoughts, but in fact they are no more real than an image of a flower is a flower. No scientific instrument can find anything in brains that is not something physical.
Epiphenomenalism. This big word is essentially the belief that consciousness really does exist, there is something going on in the brain that could be called “mind” and “experience,” but it has nothing to do with what people actually do. In this view, consciousness has no causal powers. It is like a helpless observer who can watch what is happening (like, watching a movie) but there is no way for it to participate in the action. Epiphenomenalism is an appropriate approach to some other phenomena as well, for example an experienced auto mechanic can identify problems with an engine, and tell whether it’s functioning correctly, by listening to the sounds it produces, and yet it’s obvious that the sounds do not affect the engine, and the engine was never designed to produce those sounds. So this view is like saying that consciousness is a side effect of brain function, but has nothing to do with what the brain is doing.
Epiphenomenalists are not particularly interested in explaining how consciousness arises. For them, the question is roughly equivalent to studying how an automotive engine produces sounds–nobody really cares. It has nothing to do with the function and design of the engine. There is also something of a fatalist attitude toward free will, since epiphenomenalists do not think people are able consciously to influence their own actions. It’s like your awareness of things is along for the ride and all you can do is accept whatever happens.
Panpsychism. David Chalmers has at times proposed a sort of panpsychism. The term, much older than contemporary philosophy of mind, refers to the belief that there is some element of mind and consciousness in all matter; that everything has some fundamental component of consciousness. This idea goes back to thinkers including Gottfried Wilhelm Leibniz, who proposed that the fundamental unit (or “particle”) of matter was the Monad (see Monadology) and that one of its properties was intellectual content. Chalmers’ argument is that if we assume that every particle of matter has a basic element of consciousness to it, then the appearance of complex forms of consciousness in certain types of matter can be understood simply as a form of accumulation of components. The unfortunate side effect is that you have to wonder if it’s moral to mistreat your mouse pad, and what it thinks of a mousepad’s life in the Universe. This rather Douglas Adams-esque problem is rarely discussed by panpsychists, as they usually suggest that awareness, as such, only arises in the more complex combinations of “consciousness particles.”
Dualism. There are two kinds of dualism, property dualism and substance dualism. Both forms suggest that the nature of the mind is fundamentally different from the nature of matter. Under these views, consciousness both exists, and has the potential of causal interaction with the material world. Most of the philosophers who reject dualism do so on the basis that it’s unclear how anything that is non-material can causally interact with material substances. On the other hand, the idea that mind and matter are different kinds of things seems quite common and very familiar to the average person, leading to a kind of frustration for many philosophers such as John Searle, who decries the situation that everyone he speaks to in audiences seems to want to be a dualist.
The problems of dualism are not unique to philosophy of mind. There are also dualist problems in understanding how natural law regulates matter, and how geometry has any relationship to the form and shape of physical objects. This question has a more general form in philosophical discussions of the relationship between mathematics and the sciences, since mathematics, being abstract, would seem to have no binding or necessary relationship to how physical forces and objects behave; and yet mathematics is fundamental to our understanding of nature.
The great problem with dualism, as far as most professional philosophers are concerned, has to do with the way it allows some form of “spirit” (“the ghost in the machine”) to re-emerge as a component of reality. This causes an emotional conflict with the objective purity of science, and so these guys want to avoid it at all costs.
Well there you have it. Most philosophies of mind and consciousness are some form of the above views. If you would like to know more, you might like the following lectures on YouTube:
The Magic of Consciousness by Dan Dennett (56:23)
Consciousness & the Brain by John Searle (A TED talk; 15:50)
Hard Problem of Consciousness by David Chalmers (9:18)