An example of an abstraction

People sometimes have trouble understanding the notion of selective ignorance because it's too, umm, abstract. Sometimes an example will clear it up.

Most of us who use computers use systems that include a graphical input device, such as a mouse, trackball, or finger pad, which lets us move a cursor around the screen. Such systems are commonplace today.

In fact, they're so commonplace that I snuck an important abstraction past you in the last paragraph: the notion of a cursor. The abstraction: You move the mouse and the cursor moves. What we're selectively ignoring: There is no such thing as a cursor. Putting it differently, a cursor isn't a thing.

In other words, although we can see what we think of as a cursor doing something that we think of as moving, in reality there is no thing that moves. Instead what happens is that some pixels on the screen change color for a while, in a way that creates the illusion of something moving. If we dig deeply enough into the software, we might find that there are variables somewhere that contain the coordinates of the cursor's current position, and those variables might change values from time to time; but that's as close as we come to anything moving.

Think of the mental process that allows us to treat the changes in the screen's pixels as if an object were moving on the screen. That process, whatever it may be, is deeply ingrained in our makeup. Indeed, it is so deep that we share it with other animals--as anyone who has watched a cat try to attack a cursor will agree.

Viewing pixels that change color in a certain way as a moving object is an example of abstraction. We are temporarily ignoring part of what is going on so that we can interpret it in a more useful way. This processs of selective ignorance is the essence of abstraction.

Posted by Andrew Koenig at 01:37 PM  Permalink