What do we mean when we say something is physical?
1) We conceive of physical things as having mass, velocity, momentum, energy, and forces between them that cause one physical thing to act or react in some way relative to another physical thing. So physical generally indicates something that is objectively measurable or causes something to occur that is measurable. And we know in principal at least how the matter out of which our brains are made, interacts. We may not have a complete description of all the ways molecules interact (such as a complete description of how all proteins fold for instance) but we understand that any complete description will simply tell us more about those objectively measurable interactions.
2) Generally we would say that mental properties and events are supervenient on the physical so from that aspect, mental properties and events such as qualia are physical. We might liken mental properties to a higher level physical description just as weather patterns or some other higher level description can also be described by observing the lower level interactions. The lower level interactions are closer to the ultimate cause of what occurs and we call this reductionism. That’s why we test individual neurons the way we do for example.
3) Unfortunately, mental properties and events such as qualia are not objectively measurable and generally aren’t believed to “cause” anything objectively measurable. Rather, physical interactions at the molecular level and neuronal level are believed to be the cause of all physical interactions in the brain. We understand the basics of molecular interactions and we believe these phenomena are sufficient to describe everything that occurs within a conscious brain. Thus, we often conclude that mental phenomena are caused by the supervenient physical base but that these phenomena are epiphenomenal on the physical.
There are numerous logical dilemmas that arise when we try to explain what consciousness is and what physical things are. Perhaps part of the problem is in how we define what is physical. If a phenomena is not described by describing the physical basis on which the phenomena supervenes and further, that phenomena is not objectively measurable, I would humbly submit that we have a very serious problem with our concept of the physical.
To give an example of what the problem with our concept of physical seems to be, let’s say we have a phenomena that occurs such as weather. We can define weather in all sorts of ways by measuring the objectively measurable phenomena such as barometric pressure, frontal boundaries, temperature, wind velocities, etc… These are all measurable phenomena that are supervenient on the underlying air and water molecules and the various other bits of ‘stuff’ in the air such as aerosols, pollen, dust and so on, and also the various fields that stuff is subjected to such as gravity and the EM spectrum that warms and cools the air. But if we suggested there was some other phenomena created within the weather system that wasn’t objectively measurable, something let’s call the gookiness, we might ask why we should even concern ourselves with any such property. And the answer would be that the weather was having this subjective experience, and that it was telling us about this experience through the wind and rain, the hot and cold, etc… Just because we don’t speak the language that the weather does, shouldn’t automatically exclude it from having a subjective experience, should it?
I think we use the term physical as if everyone knows what we’re talking about. If we accept that subjective phenomena are physical because they supervene on physical things, that shouldn’t raise any issues. But if we mean that physical things are those things that are objectively measurable then we seem to have a problem already. I think that’s where you’re getting to regarding the “
http://sussex.academia.edu/TomMcCle...sis_A_Hybrid_Account_of_Phenomenal_Qualities"”, that this new physical description of nature must somehow describe the properties of our mental experiences. I’ve heard that suggested before but don’t see any way that could be done given how much we know about physical interactions today. Seems to me we’ve already painted ourselves into the proverbial corner by the way we’ve conceived of what is physical.