If you mean the subjective experience with “consciousness” – i.e. the conscious perception of sensory impressions by an “inner observer” – then the trace currently ends with brain activity.What we experience correlates with the electrical signals in the brain.We know this because the change in brain activity (e.g. through medication, injury, illness, targeted stimulation, etc.) is a result of a change in the subjective content of consciousness. We even know with increasing accuracy which brain regions are related to which contents of consciousness, and what quality the brain activity must have in order for us to become aware of something (most brain activity is not known).
But now it’s going to be exciting.We know more and more about the electrical signals in the brain. But how we get from electrical signals to our extensive subjective worlds of experience, there is no pale glimmer of that yet. You cannot measure these subjective worlds of experience in themselves.For example, I can prove that someone has brain activity, because this is where measurable physiological processes are based. However, I could not prove that this person is actually experiencing a subjective world. I know that I have consciousness myself, because I am experiencing it subjectively. But in theory, everyone but me could be so-called. be a biological robot, with physiological brain activity that controls everything, but without subjective worlds of experience. This assumption cannot be refuted (or proved at present).
If you are not so involved in the matter, the following comparison with a computer may help you: In simple terms, we have a chip that calculates everything and a screen on which you can look at the result of the calculations.In terms of consciousness research, the chip is the brain, so we are in the process of examining it closely. The screen represents our subjective experience, that is, what we perceive as our personal inner and outer world. Just as the contents of the computer screen can be traced back to the activity of the chip, so our consciousness content can be traced back to the activity of the brain. Only: With the computer we obviously have a tangible screen in front of us.In the brain, we lack any physical representation of our “screen”, i.e. our subjective world of experience.
There are some philosophers who therefore say that brain activity is consciousness.Sometimes I think these philosophers may be among the biological robots mentioned above. Because my world of experience seems to me to be much more than the mere sensation of current flows. For the latter, for example, flashes of light on a black background would also do the same. But perhaps flashes of light on a black background, with enough complexity, will become a romantic sunset. Who knows?