'It is possible to imagine kinds of world very different from the world as we know it. It is possible to describe types of experience very different from the experience we actually have. But not any purported and grammatically permissible description of a possible kind of experience would be a truly intelligible description. There are limits to what we can conceive of, or make intelligible to ourselves, as a possible general structure of experience. The investigation of these limits, the investigation of the set of ideas which forms the limiting framework of all our thought about the world and experience of the world, is, evidently, an important and interesting philosophical undertaking. No philosopher has made a more strenuous attempt at it than Kant.'

Strawson, The Bounds of Sense, p.15.