Difference Engines: Move Over Mr. Turing

An Indian postage stamp depicting Panini

Proving the old adage that a good idea has many fathers, some scholars believe that one of the fathers of computing is Panini, an ancient Sanskrit grammarian who, according to commonly accepted estimates, lived in the fifth century B.C.
Almost nothing is known for certain about Panini’s life. Tradition has it that he was born near the Indus River in what’s now Pakistan. Panini’s grammar for Sanskrit is highly systematized and technical. Inherent in its analytic approach are the concepts of the phoneme, the morpheme and the root, not recognized by Western linguists until some two millennia later. His rules have a reputation of perfection—that is, they are claimed to fully describe Sanskrit morphology, without any redundancy. A consequence of his grammar’s focus on brevity is its highly nonintuitive structure, reminiscent of contemporary «machine language» (as opposed to «human-readable» programming languages). Panini uses metarules, transformations and recursions with such sophistication that his grammar has the computing power equivalent to that of a Turing machine. In this sense, Panini may, indeed, be considered the father of computing machines. His work was also the forerunner to modern formal-language theory. Paninian grammars have also been devised for non-Sanskrit languages. The Backus-Naur form (sometimes called the Panini-Backus form), or BNF, grammars used to describe modern programming languages are similar to Panini’s grammar rules. It’s not even known whether Panini used writing for the composition of his work. Some historians argue that a work of such complexity would have been impossible to compile without written notes, while others allow for the possibility that he might have composed it with the help of a group of students whose memories served him as «notepads.»