Calculus is a powerful mathematical toolbox for dealing with phenomena in a state of flux, from the flow of water to the expansion of the cosmos. As such, a better name for it would be ‘fluxions’ – a term coined by Isaac Newton, one of the two 17th-Century mathematicians regarded as its inventors, the other being the German Gottfried Leibniz. Not that Newton saw it that way. Having invented it in secret in the 1660s, he was horrified when Leibniz went public with similar methods, having independently discovered them about 10 years later.
Newton launched an unjustified campaign of character assassination against Leibniz, yet could not stop the adoption of his rival’s name for the technique (from the Latin for ‘counting stone’). It’s now known that some basic ideas in calculus had been explored much earlier. For example, Archimedes showed how to work out the area enclosed by curves by dividing it up into tiny strips. This is a trick exploited in integral calculus to work out the total effect of a series of tiny changes. However, none of Leibniz and Newton’s predecessors realised the full power of what they were working on.