The Second Law of Thermodynamics demonstrates the idea of entropy, the tendency of ordered energy to free itself and thus break apart the system that contains it and dissipate that system into chaos. When applied to communications theory, entropy increases not only with noise but with the density of information--particles of possible meaning crowded into a channel at too high a rate for the receiver's decoding ability. Entropy is lowered by redundancies (familiar information) which allow the receiver to anticipate and thus comprehend what will be said next. Entropy is a metaphor in physics and chemistry and a metaphor built on a metaphor in communications theory, where the idea of noise substitutes for the unavailable energy, which is then calculated mathematically and not measured empirically. By examining the idea of entropy, rhetorical theorists can avoid the particular limitations analogical thought tends to establish and explore qualitatively the factors that tend to disorder and to order in rhetorical systems. (RB)