When Aristotle was investigating matters of biology, physics or astronomy, he would observe the phenomena he was exploring as carefully as he could. A few philosophers who followed in his wake rooted their thinking in observation too. But around the year 1600, people began using observation in a new way. They would actively try to disprove their own favourite ideas. Communities of investigators could use the rigours of experimentation to differentiate between the ideas that captured reality successfully and the seductive ideas that didn’t.
As this ‘natural philosophy’ evolved, it morphed into ‘science’. Investigators developed new ways to capture the complex patterns that their observations revealed. Whereas Aristotle had used simple words to describe motion — faster, slower, pushing, pulling, pushing together, pushing apart, carrying, rotating, combining and separating — Newton used mathematics to model movement. He had come across Descartes’ revolutionary new ‘analytical geometry’, which used numerical coordinates to describe the position of a point in space. He developed integral calculus to work with the coordinates and, combining this approach with concepts such as force and his three laws of motion, he was able to describe how objects move through space with an uncanny predictive power. Everything could be calculated, from the trajectory of a bullet to the orbit of a planet, or even the trajectories a spacecraft might follow to take people to the moon.
Universities and governments began funding science and people worked out how to apply scientific methods to an ever wider range of phenomena. Anything that was observable and repeatable entered the remit of science.