But, everything about a circulation can be measured physically - the flow rate, the physical appearance of the blood, the chemical content of the blood, etc. but can you measure thought - what is it's color? how much does each thought weigh? — TheMadFool
When you ask how much each thought weighs or what is the colour of thought, you are asking how much each circulation weighs or what is the colour of circulation. In the case of blood circulation, you can measure its features (flow rate, pressure, cellular content, gaseous content, ionic content, protein content, etc) which, individually, are not the circulation of blood itself. Same with thought. Like blood circulation, thought is a process
which occurs in a defined space (the brain or certain areas of the brain) and which is determined by the molecular properties of the medium in which it occurs (the brain or certain areas of the brain).
Too many cells in blood plasma and blood circulation is going to slow down; too many proteins and the same thing is going to happen. Too many cells in the brain (i.e., a tumour) and you are not going to be the normal you. Too much THC in your brain and you are not going to be the normal you, either; not enough oxygen in your brain and you
will feel its effects. You have a stroke, blood gets inside areas of you brain where it should not be, a short circuit occurs, and you loose consciousness not because consciousness decided to go but because the conditions required for there to be consciousness are not there anymore.
That the self changes when the chemical composition of the brain changes I think is a strong indicator of the self's dependency on the brain and of the self's physicality.
When you die, oxygen stops flowing to the brain (the heart stops pumping blood). Oxygen is a requirement for the production of ATP, which is in turn required to maintain chemical gradients across cell membranes; these chemical gradients are then used to do work.
No oxygen, no ATP, no chemical gradients, no work. A cell does work to maintain a state of low entropy which is compatible with life. If a cell is unable to do work, entropy does its part. Decomposition of the body (or cells) is entropy in action. If the brain is unable to maintain the molecular conditions required to generate thought (unable to maintain their ordered state), thought does not occur (or deviates from normal).
The question is: why the state of entropy maintained by living cells allows life?
I am not a neurologist nor am I studying neurology (I haven't even finished my degree), so please take my words with caution. There's a book called Molecular Biology of the Cell (6th Edition) which I think is available for free online (maybe at the NCBI's website) which explains quite neatly a lot of the processes which maintain cells alive. I think that understanding these processes gives insight into phenomena such as the mind, free will, etc. There is also a book called Human Physiology: An Integrated Approach (7th Edition), which talks more about systems biology, and which might be easier to digest if one does not have a background in cell biology (I think you could also find it for free online). The books are very well written so I'd recommend anyone one to give them a look.