How Do You Know?

Epistemology is traditionally classified as one of the fields of philosophy, and some psychologists have been content to leave it to the philosophers. In my opinion, the problem of how we know is an absolutely basic concern of psychology, but whether you consider my remarks to be psychology or philosophy I really do not care, as long as you are willing to grant me that the problem is a fundamental one. Naively, it seems to us that the outside world, the world around us, is a given; it is just there. I look out and see you sitting in front of me; around you I see walls that enclose the room and stop me from seeing farther. But my world, the world I live in, does not seem to stop at the walls; beyond them, in the same continuous space, there are cities, roads, rivers, oceans, all of which have some determinate loci in my picture of the world. We all feel as if our experiencing of the world around us were quite direct. However, the apparent immediacy of this experience has to be more or less illusory because we know that every bit of our information about external things is coming in through our sense organs, or has come in through our sense organs at some time in the past. All of it, to the best of our knowledge, is mediated by receptor activity and is relayed to the brain in the form of Morse code signals, as it were, so that what we experience as the "real world," and locate outside ourselves, cannot possibly be anything better than a representation of the external world. (Epistemologists can argue about whether it is even that, but I am willing to take for granted the existence of a physical world that is being represented.) The afferent nerve impulses that link the representation to the reality are extraordinarily dissimilar to either, however formally considered. This is the point of Brunswik's (19S2) lens analogy: information about