Only_Humean:
But the process of tactile and electromagnetic intervention to the physical brain, the illusion of scent or the cause of laughter through physical procedure (my reference [and perhaps yours]: the stimulation of “A.K’s” brain in neuro-medical context in the Neuroscience for Kids article: “Laughter and the Brain”) are, from our side of the fence, ultimately phenomenal (i.e. they are entirely experiential things composed only or ultimately from experience or our experience of them [Arthur Danto]). What we call ‘physical’ is actually experiential, or reality in the form of oneself and one’s personal experience.
The things that we perceive are actually composed of our experience of them (conceptually evident in the question of whether or not things continue to exist when we no longer personally perceive them). A neuroscientist, preparing to work on the brain of an epileptic patient, experiences only a phenomenal (experiential) brain, phenomenal medical and neuroscientific equipment, a phenomenal patient, etc. etc. He does not experience a brain, medical equipment, or the patient as they are (if these even exist) when no one is perceiving them or if cerebral cortices (the only part of the brain responsible for consciousness) did not exist (and these objects, through some ‘miracle’ of the laws of physics, somehow meaningless and fortuitously obtained).
Explanation of the Process of Perception holds that there are two aspects of reality (for those who believe that reality has a mental and physical aspect): there is the neuroscientist, the brain upon which he/she prepares to work,the surrounding medical and neuroscientific equipment, etc. as they exist in the complete absence of anyone perceiving them, or how they are if all consciousness in the universe were to instantaneously cease to exist (the neuroscientist would drop to the floor)—and there is the Percept: a subject of experience and how he/she/it perceives and tactically experiences the brain, neuro-equipment, etc.
These two are different things (as the stuff in the absence of a subject of experience is entailed to exist in some non-experiential form in the absence of anyone perceiving them). My thesis is that, on reflection, one finds that the ‘physical’ is a wholly different existence from the ‘mental’ and that–aside from magic–the physical cannot create or have anything to do with the existence of the subjective experience as the physical (if it can exist in the complete absence or nonexistence of any and all experience) is not experience and cannot use itself to produce or control something it, itself, is not.
My conclusion, then, following Berkeley (in his way), is that we should dispense with the extra baggage of the physical and admit (if we will) to a homogeneous reality in which the only thing that exists is personal subjective experience on a microscopic (us) and macroscopic or infinite scale.