`  == Misstating what ``analog`` means ==  While the explanation given (direct correspondance to a physical property) may have originally have been true (I will not presume to judge this), it is not in accordance with modern usage. The difference between analog and digital can, with some oversimplification, be stated as the difference between a continous dependency and one that considers (e.g.) a signal a series of discrete information units. (This statement is off the top of my head and may be sub-optimally formulated; the principle is still correct.) A physical dependency is only needed in as far as everything (including the digital signals in a computer) ultimately has some physical connection.   `