Seeing a tree

“Seeing a tree” seems for all the world like a simple thing. You turn toward the tree and open your eyes, and there it is. But we know it is not simple at all. A great deal of processing goes on behind the scenes. We might say that a perception consists of two parts: first, the raw data that come from the senses, and second, the assumptions that we make in interpreting the data. These assumptions taken together, forms a theory about what the world is like.

Our commonsense view of how perception works is part of such a theory, which we might call --with obvious bias -- the Natural Theory. The gist of it is this:

“The Natural Theory”: We have experiences such as “seeing the tree” because our bodies, including our eyes and ears interact with physical world. The physical world exists in dependent of us -- that is, it would exist even if we did not, and it continues to exist even when we are not observing it. The physical world impinges on our senses, causing us to have experiences that represent, more or less accurately, how things are. The experiences, in turn, cause us to have true belief about tree.

The Natural Theory is a rival of other theories, such as Idealism and Direct Realism. Basically, it combines Indirect Realism with a dose of common sense. ~Page 148