The Perceptual World of the Individual

In one of Bishop Berkeley’s dialogues, two philosophers are looking at a distant castle, only a tiny speck on the horizon. They agree that they can both see it, but are unable to make out its doors, windows and battlements. From where they are, it looks like a small round tower pointing upwards on the distant hilltop. But since they have been to the castle, they know that it is a large square building with battlements and turrets, and they agree that what they see as a small grey tower is not in any sense an adequate picture of the castle as it exists some miles away. It may be concluded that the apparent world of objects presented to us in our sense perceptions is nothing but a picture of something and not the thing itself; and that it is often an inadequate picture of the ‘real’ outer world as it actually exists.

This in itself is to say little more than that our knowledge of the world is fragmentary and is limited by the one-sided view of things which we get from our own particular perspective. Each of us can only perceive things through the mind and senses from the particular point in time and space where those instruments are. But our dependence on this inadequate data, and the fact that we have to act on it, no matter how inadequate it may be, compels us to adopt a strategy of estimating probabilities, of interpreting the available data to yield a provisional decision as to how things are, and then to act on it. In practice we go further than the evidence warrants, and so our perceptual world is not merely made up of the sense data that we have recorded, but also of the way in which we have chosen to interpret it; and the discrepancy between what we actually see and what we infer to be there, can be much more than mere fragmentariness. It may well be positively misleading and wrong.