To continue with some fundamental descriptions, on page 41 of
"Life, Itself":
Robert Rosen wrote: "Our first basic dualism has separated
the universe into a self and its ambience. For each of us, this separation is
absolute, indubitable, and unequivocal, though it may be different for
different selves. Our second basic dualism concerns the way we partition our
ambiences, the way we manage our perceptions of the external world.
At this level, we have no universal principles to guide us,
nothing given to us, like the distinction between the inner world of the self
and the outer world, what we called the ambience. It rests rather on a
consensus imputed to the ambience, rather than on some objective and directly
perceptible property of the ambience. It is the dualism between systems and
their environments.
Roughly speaking, a system in the ambience is a collection of
percepts that seem to us to belong together. It would be hard to imagine a
less precise definition of anything, but that is inherent in the very idea of
system. The abstract concept of systemhood is indeed a very difficult one to
grapple with, as is the related notion of set-ness. It is at the same time
familiar in the concrete garb of everyday experience and alien when we attempt
to characterize it in isolation, as a thing in itself, apart from any specific
material embodiment.
Indeed, in mathematics, set-ness is such a basic and familiar
notion that it took two thousand years for it to be recognized explicitly;
even then, it took a strange mind (as contemporaries reported Cantor was) to
see it and to deal with it. Once it was pointed out, and its central role in
mathematical thought made explicit, then everyone saw it. Indeed, within a
generation, and in the teeth of paradoxes it had already spawned, David
Hilbert was saying, "From the paradise created for us by Cantor, let no man
drive us forth."
The notion of system-hood is at that same level of generality
and plays the same kind of role in our management of the ambience. As noted it
segregates things that "belong together" from those that do not, at least from
the subjective perspective of a specific self, a specific observer. These
things that belong together, and whatever else depends on them alone, are
segregated into a single bag called SYSTEM; whatever lies outside, like the
complement of a set, constitutes ENVIRONMENT.
The partition of ambience into system and environment, and
even more, the imputation of that partition to the ambience itself as an
inherent property thereof, is a basic though fateful step for science. For
once the distinction is made, attention focuses on system. Systems and
environment are thenceforth perceived in entirely different ways, represented
and described in fundamentally different terms. To anticipate somewhat, system
gets described by "states", which are determined by observation; environment
is characterized rather by its effects on system. Indeed it is precisely at
this point that, as we shall see, fundamental trouble begins to creep in;
already here.
The growth of science, as a tool for dealing with the
ambience, can be seen as a search for special classes of systems into which
the ambience may be partitioned, such that (1) the systems in that special
class are more directly apprehensible than others, and (2) everything in the
ambience, any other way of partitioning it into systems, is generated by, or
reducible to, what happens in that fundamental class. Newtonian mechanics, for
instance, thought it had found such a class; so, today does quantum theory.
But it is, above all, a special class, embodying an equally special way of
coping with the system-environment dualism itself. Whether this is enough is,
at root, the basic
question."