The subjective frame cleaves the experiential field into two distinct regions: the world and the self. Some aspects of experience belong to one, some to the other. Object and subject are disjunct categories: not apples and oranges but apples and ideas about apples. It also gives rise to two perspectives. One looks upon the object-- implicitly from all possible points of view, both physical and cognitive (while actually from one point of view at a time). The other looks from the subject, which is literally a dimensionless point of view (while potentially it is all such viewpoints). The object-- even the object of thought-- has extension in space and time and various sensory qualities. The subject has no qualities and no extension. What it does have, we shall see, is intention.
The subject-object dichotomy itself can be examined from either perspective. We can look at the organism as physical and note that its responses are a product both of an objective environment, of which it is a part, and of its own internal programs. We can infer an experience which is an inner representation of the environment and try to grasp the process whereby it is constructed. Or we can examine our own field of experience for its internal logic and structure, in order to comprehend the "deduction", from sensory input, through which the external reality has been unconsciously constructed. In the first case, we begin with the world as primary and given (with our physical bodies and brains as part of it), and try to understand the arising and place of consciousness in that scheme of things. In the second, we begin with consciousness as primary and given, and try to understand the system of cognitive beliefs which in their sum give us the experience of a real world.
This bilateral creation of experience is something like an algebraic product of two factors-- world and mind-- an "equation in two variables":
where o is the object and s is the subject. Of course, this equation can never be "solved" except by arbitrarily holding one variable constant while observing how experience depends on the other. And this is an operation performed intentionally from outside the system. In the wild, the two factors always function together. Physics attempts to simplify the epistemic situation by eliminating the subject, making experience a straightforward function of causes in the physical world. Psychology, on the other hand (to the degree that it is not merely an extension of physics), might seek to control the input of the environment in order to observe the dependency of experience on the subject's mind.
This "equation" can implicitly express either a realist (as above) or an idealist bias. The world (and the body as part of the world) may be taken to be primary and objective, while experience is a subjective function of it. Or the relation can be turned inside out, with experience as given, and with the world and the body as constructs:
The Mind-Body Problem is the fact that neither expresses the situation adequately, so that it is impossible to decide between them.
The epistemic situation of embodied minds (the M.B.P.) entrains three limitative consequences. These are that the world cannot be known: (1) as it is "in itself", independent of knowing minds; (2) in its absolute entirety; (3) impartially, apart from biases and interests originating in embodiment and cultivated through learning. These consequences can be restated as follows:
1) the set (o,s) cannot be known except as elements of E;
2) the set (o,s) is necessarily larger than the set E;
3) generally, f'(o,s) and f(o,s) are not identical.
These perspectives are also facts of everyday life. As a consequence of living in bodies, we are one-sidedly bound up with our own existence, and literally with our point of view in space, separate and distinct from others-- unable to experience other minds from within, nor our own from without. As social beings, we have developed empathy to compensate for the one condition, detachment for the other.
The concept of mental illness is but an exaggeration of the gulf between these perspectives. When viewed externally, mental illness is a departure from normal behavior, a nervous or chemical disorder. Viewed from within, it may be a novel way of organizing experience, following its own reasons, and perhaps a glimpse of truths for which normal consciousness is not prepared.
These perspectives also divide knowledge or intellectual inquiry into two broad categories: ontology, which asks what is, and epistemology, which asks how the mind gets and justifies its knowledge of what is. These have been retained as branches of philosophy, but the distinction between world and self has also given rise to specialized sciences such as physics and psychology.
The Mind-Body Problem is elusive and confusing because we are at the core of it. A function of our way of looking, it is wherever we turn our gaze. Subjective consciousness has opened a second perspective to us. When the subjective viewpoint is regarded implicitly through objectifying eyes, mind appears as a subtle kind of matter. Mind and matter are then seen as two complementary, but incompatible, kinds of "stuff". How, we might wonder, can the thought of moving one's hand bring about the hand's movement; how can physical discharges in nerves bring about the sensation of touch? Here we detect the hidden effects of self-reference, a fault in the problem itself. Hence Gilbert Ryle's famous dismissal of the whole quandary as a "category mistake". But the problem does not go away merely by declaring it vanquished. Its very persistence is a sign of the fundamental and unique dilemma of the self-conscious mind, located upstream, so to speak, from all ordinary strategies of thought. The task is to understand the dilemma itself, and the principal obstacle is the pernicious fact that the mind cannot stand outside the very dilemma it attempts to model. For thinking, like perception, is necessarily done from an external perspective, whereas the subject-- the agent of thought-- is the internal perspective.
The Mind-Body Problem is actually a complex of inter-related ones. And these fall roughly into three types. The first concerns the classical incompatibility of mind and matter; secondly, the problem of reliable knowledge for subjective beings; finally, the difficulties posed by dealing with other subjective minds. All stem ultimately from the fact of self-consciousness.