Understanding as a model Gregory Chaitin, a noted computer scientist, propounds a view that comprehension is a kind of data compression. In his essay "The Limits of Reason", he argues thatunderstanding something means being able to figure out a simple set of rules that explains it. For example, we understand why day and night exist because we have a simplemodel—the rotation of the earth—that explains a tremendous amount of data—changes in brightness, temperature, and atmospheric composition of the earth. We have compressed a large amount of information by using a simple model that predicts it. Similarly, we understand the number 0.33333... by thinking of it as one-third. The first way of representing the number requires an infinite amount of memory; but the second way can produce all the data of the first representation, but uses much less information. Chaitin argues that comprehension is this ability to compress data.