He writes, In PET studies like Fink et al., the contrast has to be designed very carefully so that exactly the same mental processes can be assumed to occur in the 2 conditions under comparison, except for one well-specified difference. I would argue against any fundamental difference. But we can still compare those aspects that are IN consciousness to those that are not. We can compare waking and sleeping, alertness and drowsiness, immediate experience and its fading in immediate memory, attended vs. unattended streams of information, remembering vs. knowing, novel vs. automatic skills, and much more. Global effects are routinely studied in science, though they are sometimes hard to spot because they are so pervasive.
Gravity is a good example in physics.
Until Newton's generation realized that planetary motion implied very low gravity in space, the comparison case could not be observed on earth. All the basic physical laws apply to such pervasive phenomena. A recent example is the universal background radiation discovered at Bell Labs a couple of decades ago, which is now taken as crucial evidence for the Big Bang. These are promising domains for further work. Again, let me thank all participants.