Getting information

In an earlier post, I wrote:

That leaves, as one of the basic problems for a cognitive agent, the problem of getting information about the world.

In this post, I want to discuss why that is a problem.

Many people seem to hold the view that sensory cells in the body passively receive input from the world, and that how we perceive the world depends on what we do with that passively received data.  That seems to be the view of proponents of sense-data accounts and of proponents of computationalism.