Oh I'd say we have plenty of ways to measure and observe consciousness. We can measure brain activity during sleep and understand with some precision whether someone is dreaming or not, which is a state of consciousness. We can give someone a psychoactive drug, and ask them questions about how their consciousness has been altered.

> Forward movement can be measured. And if you removed parts of the car you would eventually get down to the bare minimum required for forward movement because you could observe it. You cannot do this with consciousness.

What makes you so confident of this? We actually have plenty of evidence in this direction with consciousness. We can observe that lesions in different parts of the brain have very predictable effects on consciousness. We can observe that psychedelics like LSD reduce sensory inputs to the thalamus, having very predictable effects on consciousness. Consciousness is obviously a process which responds to physical intervention, so why should we jump to the conclusion that it somehow exists outside the bounds of the physical world rather than assuming that it's just one of many physical phenomena we have yet to fully understand?

To give an example, we cannot reliably predict the movement of the economy. We can understand some of the forces guiding it, we can try to understand it in terms of certain metric, and we can take some actions to get the results we want, but ultimately we can't point to any one thing and say: "this is the economy". It's an emergent property of a vastly dynamic interconnected system of billions of independent actors, and as a result we will probably never be able to fully pin it down. But we don't assume that the economy moves as the result of some magical force controlled by the gods, we rightly know it's just something out of our grasp.

Interesting point about observing conciousness changes in ourselves - that does indeed give us some insight. Though I'm not sure we could use this tool for a lot of the answers, it doesn't seem terribly precise (and doesn't let us know much about concious states that cannot be achieved with human brains).

> why should we jump to the conclusion that it somehow exists outside the bounds of the physical world rather than assuming that it's just one of many physical phenomena we have yet to fully understand?

I don't believe the cause of conciousness is magic or supernatural, it'll surely be a physical phenomenon. Just not sure if it emerges via some phenomenon that we haven't discovered yet.