Richard Polt on why you can't explain things physiologically.
The sciences take it for granted that there are beings, and presuppose an
understanding of the being of beings; this seems to cut them off from the
question of be-ing. If we tried to explain be-ing sociologically, for example,
we would have to take society for granted as something with a self-evident
way of being. We could then give a factually correct description of how people
operate within society and how their behavior brings with it certain beliefs
about what it means to be. In doing so, however, we would have to leave
our own beliefs about what it means to be unquestioned, so that they could
serve as the stable basis for our empirical research. The question of the status
and origin of our own understanding of the being of beings would have
to be left unaddressed. Similarly, we might be able to give a physiological explanation
of the workings of the brain, “explaining” consciousness in terms
of the various complex neural responses that are associated with it. But in order
to do so, we have to assume that the brain and consciousness have a certain
way of being that we understand. If all our observations depend on this
understanding of the being of brains and consciousness, then our observations
cannot provide a satisfactory explanation of how the understanding of
the being of beings occurs. If these considerations are valid, then any scientific
attempt to explain be-ing is circular: it must presuppose a given sense of
the being of beings. Now, if we are willing to embrace the circle by revising
this sense in the course of our investigation, the circle may not be vicious;
this is what Being and Time does, after all (SZ 153, 315). But then we are engaging
in philosophy, not just empirical science. We are struggling with the
limits of our sense of the being of beings, and thus experiencing it as contingent
and finite. This distinctively philosophical experience is needed in order
for being to trouble us.
Pp. 62-3