Inner and Outer

Two people converse. They see and hear each other. They also see their surroundings and hear other sounds. Thus, they share a publicly accessible, empirically discernible, objective, material realm. Each also accesses a private, inner, subjective, mental realm of memories, imaginings, thoughts, emotions, motives, apprehensions and anticipations. Thus, experience has two layers or levels which, however, are not ontologically equivalent.

Objects pre-existed subjects which generate their individual subjectivities. Despite its lack of objectivity, the inner realm is powerful, full of ideas, reasons and motives. We need to understand both realms, reducing neither to the other. We exist where they intersect. The entire content of the inner world is derived from natural and social environments. Language is social before it is internal. However, it is with the inner powers of intellect and imagination that we understand and set out to change the external world. Mind is creative, not passive; a god, not a mirror. It developed with manipulation, not as mere cognition.

The inner world includes dreams. Because, when dreaming, we seem to leave the body and to enter a realm where we can meet (dream about) the dead, it was thought that:

the inner world was inter-subjective or objective;
it touches the visible world;
we enter it temporarily in sleep and permanently at death;
it has other inhabitants. 

In fact, it is still inhabited by myths and fictions.

We understand the inner world through meditation, psychology and literature, the physical world through physics, chemistry and cosmology, the biological world through Darwinian analysis of natural selection underlying species diversity and the human world, I suggest, through Marxist analysis of economic realities underlying social appearances.