Subjective experience is an interesting one. This is all speculation, but sometimes that's what you need to do to figure out what to test.
As others have said, I believe that the ability to 'redirect' mental output back in via feedback loops is a critical component of subjective experience. The ability to talk to oneself in the mind, or to hear a song that isn't playing, visualize a picture, remember a smell, or tactile sensation, pain ... I think if you lack the ability to do any of these things, you probably have no subjective experience, and the more of these things you can do, the richer your subjective experience is. That's just my guess.
Some people seem to think it's an entirely unscientific matter, but I'm not so sure. Mostly we are limited by technology that can tell us what is going on with sufficient resolution, EEGs are incredibly coarse grained, and even the fMRI only measures increased blood flow. And then of course there is the matter of interfacing, which we've gotten better at in recent years.
If we had the ability to link up the audio cortex of 2 people, for example, I think we'd start to see that the manner in which information is allowed to flow between different processing areas (in this case people) actually has a lot to do with shaping subjective experience. If everything I said to myself was audible in your mind's ear, and vice versa, and same for visual experience, and for the other sensory modalities, and even memory and emotional state, would it not be fair to say that maybe we are having the same subjective experience at that point? After a month or two of being connected like this, would the subjects continue to have any sense of separate identity still?
We can do the opposite, and we know a few things about how the subjective experience of a person with severe epilepsy changes when the connection between the 2 hemispheres is severed. A non-epileptic can experience something similar by having 1 hemisphere of the brain temporarily anesthetized.
Similarly, let's say my primary visual cortex starts to go on the fritz. My subjective experience will probably start to degrade in some way. Let's say I then get a chip hooked up that does basically the same thing, feeds the same signals up to V1, V2, MT, MST, so on and so forth, and of course responds to the same downward feedbacks. Further say that my subjective experience is then restored to what I remember it being. Is this not evidence that subjective experience is a result of information processing/flow?
As for the why? Why have subjective experience? What evolutionary advantage might it confer, if any? I don't know. Perhaps our ability to do higher-level reasoning -- take math for example -- requires it. If somebody shut off your inner monologue completely, and prevented you from just talking out loud and hearing yourself, how many different tasks would you no longer be capable of doing the same way? Obviously we have machines that can do things like calculate and solve equations, but maybe subjective experience is integral to the particular way that biology has chosen to solve the same problems. Perhaps nature found a way in which reflexive information processing could give rise to symbols, and that this was more generally useful than a dedicated area of the brain capable of carrying out rote calculation. I don't know.
I think what's reality limiting us is the ability to image and the ability to rearrange and test. Once we get those nailed down I think we'll make a lot of progress on what exactly subjective experience is.
As others have said, I believe that the ability to 'redirect' mental output back in via feedback loops is a critical component of subjective experience. The ability to talk to oneself in the mind, or to hear a song that isn't playing, visualize a picture, remember a smell, or tactile sensation, pain ... I think if you lack the ability to do any of these things, you probably have no subjective experience, and the more of these things you can do, the richer your subjective experience is. That's just my guess.
Some people seem to think it's an entirely unscientific matter, but I'm not so sure. Mostly we are limited by technology that can tell us what is going on with sufficient resolution, EEGs are incredibly coarse grained, and even the fMRI only measures increased blood flow. And then of course there is the matter of interfacing, which we've gotten better at in recent years.
If we had the ability to link up the audio cortex of 2 people, for example, I think we'd start to see that the manner in which information is allowed to flow between different processing areas (in this case people) actually has a lot to do with shaping subjective experience. If everything I said to myself was audible in your mind's ear, and vice versa, and same for visual experience, and for the other sensory modalities, and even memory and emotional state, would it not be fair to say that maybe we are having the same subjective experience at that point? After a month or two of being connected like this, would the subjects continue to have any sense of separate identity still?
We can do the opposite, and we know a few things about how the subjective experience of a person with severe epilepsy changes when the connection between the 2 hemispheres is severed. A non-epileptic can experience something similar by having 1 hemisphere of the brain temporarily anesthetized.
Similarly, let's say my primary visual cortex starts to go on the fritz. My subjective experience will probably start to degrade in some way. Let's say I then get a chip hooked up that does basically the same thing, feeds the same signals up to V1, V2, MT, MST, so on and so forth, and of course responds to the same downward feedbacks. Further say that my subjective experience is then restored to what I remember it being. Is this not evidence that subjective experience is a result of information processing/flow?
As for the why? Why have subjective experience? What evolutionary advantage might it confer, if any? I don't know. Perhaps our ability to do higher-level reasoning -- take math for example -- requires it. If somebody shut off your inner monologue completely, and prevented you from just talking out loud and hearing yourself, how many different tasks would you no longer be capable of doing the same way? Obviously we have machines that can do things like calculate and solve equations, but maybe subjective experience is integral to the particular way that biology has chosen to solve the same problems. Perhaps nature found a way in which reflexive information processing could give rise to symbols, and that this was more generally useful than a dedicated area of the brain capable of carrying out rote calculation. I don't know.
I think what's reality limiting us is the ability to image and the ability to rearrange and test. Once we get those nailed down I think we'll make a lot of progress on what exactly subjective experience is.
