Collection 4: "The Math Instinct" by Keith Devlin

Instead of retracing his steps—which may have been obliterated by the wind blowing across the sands—he faces directly toward his home and sets off in a straight line, not stopping until he gets there, seemingly knowing in advance, to within a few paces, how far he has to go.

But the only known method is to use a technique known as “dead reckoning.”

Developed by the ancient mariners of long ago, the method was called “deductive reckoning” by British sailors, who abbreviated the name to “ded. reckoning,” a term that in due course acquired an incorrect spelling as “dead reckoning.”

Dead reckoning requires the accurate use of arithmetic and trigonometry, reliable ways to measure speed, time and direction, and good record-keeping.

The main impetus to develop accurate clocks came from the needs of sailors who used dead reckoning to navigate vast tracts of featureless ocean.

The main impetus to develop accurate clocks came from the needs of sailors who used dead reckoning to navigate vast tracts of featureless ocean.

In terms of today’s computer technology, evolution has provided Ahmed with a brain that amounts to a highly sophisticated, highly specific computer, honed over many generations to perform precisely the measurements and computations necessary to navigate by dead reckoning.

But just because something comes naturally or without conscious awareness does not mean it is trivial.

After all, almost fifty years of intensive research in computer science and engineering has failed to produce a robot that can walk as well as a toddler can manage a few days after taking its first faltering steps.

Its tiny brain might have a very limited repertoire.