The conventional view appears to be that perception is passive. Observations somehow pop into our heads, and we just have to apply logic to determine what it is that we are observing. However, getting useful information about the world is more difficult than that, as I suggested in an earlier post.
We often hear variations of the slogan “cognition is computation” and sometimes people seem to be taking that as fact rather than as a slogan or a hypothesis. It is a slogan that comes from the idea of perception as passive. I am suggesting “cognition is measurement” as an alternative slogan and hypothesis. I use the term “measurement” broadly, to describe activity undertaken get useful information about the world. So I will take perception to involve measurement activity.
The Heretical Philosopher 