I would like to write down some thoughts after the first day of the conference. I think it is becoming clearer to everyone what Presence is about and what is not.
Presence is a word used to describe a phenomenon. It is also used to describe a field of research. This makes discussions confusing sometimes. Let us look at the Presence phenomenon.
The Presence phenomenon begins with a qualia, the subjective experience of being, being someone, being somewhere. This is the central mystery of human existence, I think, and it is inaccessible to science, at least as far as we can tell today. It is frustrating that the most fundamental of experiences is at the same time so remote. We cannot tinker with it. Or can we?
The Presence phenomenon can be reduced to measurable terms: we can measure Presence if we define it by benchmarks with real situations. That is, we talk about measurable successful sensorial/interaction replacement using digital media (Slater). Success here is thus defined by comparison with what real situations generate in humans in term of measurable things such as heart rate or blood pressure, or even subjective descriptions in standarized tests. "If you respond as if it were real, then it is Presence" (see Mel Slater's interview).
This is not as deep as taming the qualia phenomenon, but it is at least accessible to science. So we must stick to it unless somebody comes up with a better, measurable definition of the phenomenon of interest.
Then we can talk about the field of Presence. Well, now that we have a phenomenon, we can talk about the field that studies this phenomenon. What causes it? What modulates it? Can it be explained in terms of other theories? Can we come up with a simple theory for it, or at least some principles to begin with? Do we need to study other phenomena before we can construct a theory? For instance, my pet theory is that if sensory inputs are consistent with a model in the brain, then Presence is high, and the simpler the model, the higher the Presence score. It may be a wrong principle (far from a theory), but at least it is testable. Call it the Kolmogorov principle of Presence.
Finally, I think that since Presence happens in the brain (no brain, no Presence), the theory of Presence will be in the realm of cognitive neuroscience. And it will have a lot to do with Information science as well, since the brain is dealing with information processing.