The first thing I need to do before I try to answer the question is define what you mean by consciousness. Consciousness is such a broad term as everyone has different opinions of it. Consciousness can refer to someone having awareness, or of being self-aware, as well as brain activity or no brain activity. So if I was asked if we can explain consciousness, in an aware state, then I do not believe we can explain it in purely physical terms. If I was asked if we can explain consciousness, in a state of some type of brain activity, then indeed I believe we can explain consciousness in purely physical terms. The readings from Paul Churchland give adequate definitions and examples of how physical terms may explain consciousness, and the readings from Thomas Nagel help make you think otherwise if there is such a thing as having consciousness.

In Churchland’s reading, Churchland effectively used the identity theory in a way we can understand the identity of something such as its high oscillatory frequency, sound waves, motion of molecules to the material itself such as light, noise, and heat and cold. His explanation of the identity theory is to compare the mental states with the brain states. Another term he introduces is “intertheoretic reduction” which is the comparison between new principles and old principles.

If I were asked hundreds of years ago the same question, I may have a different answer due to what we know now thanks to modern science. Thankfully, modern science or neuroscience now explains more in depth the principles of things, whereas back in the day, the understandings of things may be true, but not considered an “advanced understanding” or technical understanding.

Thomas Nagel’s reading really made me think twice about whether or not we can even believe in something having consciousness. The example of the bat, where only the bat knows what it is like to be a bat, is used effectively to show that we are limited to the understandings of certain things. Another point that Nagel mentions is that we may have our opinions, but our opinions are subject to questioning due to others point of views.

I feel that some of the physical terms Paul Churchland introduces effectively explain consciousness in the state of brain activity, but not in the state of awareness or of being self-aware. Today, technology has come a long way where we are able to monitor the brain waves of individuals. With the understanding of these physical terms, neuroscience technology can be used to determine if we are indeed conscious or unconscious. By measuring the brain waves frequency with an electroencephalogram or EEG, we can determine if the individual is conscious (frequency is relatively high) or unconscious (frequency is relatively low or close to 0). In the case of using physical terms to determine if someone has awareness, or are self-aware, it’s just something I do not see plausible. You can measure brain activity to determine if someone has consciousness, as I have described previously, but I do not see how you can measure awareness. In that sense, I would support Nagel’s theory that we may never know if something has consciousness, or even if consciousness exists.

If, as you propose, consciousness is inexorably linked with the self (our perceptions of self), then you would suggest that those perceptions comprise our consciousness? That is, our sense of self; our relating to others, our perceptions of where our position is, our memories, our interests, etc. all are important elements of consciousness?

I think it is your contention that the consciousness of self can't be physically measured. But, a second question I pose to you is that, how else may be it be measured? Presumably in the nonphysical? But if this is true, how exactly does the nonphysical (consciousness as self) interact with the physical (consciousness as brain activity [emotions, etc.])? Personally, I think that to suggest that the nonphysical has direct relationships with the physical is more absurd than just explaining consciousness in the context of the physical all together. And if we do that then it doesn't seem all together outlandish to suggest that consciousness may be measured (if even on subjective grounds).