During Isaac Newton's time, several contemporaries were making similar scientific discoveries:
- *Gottfried Wilhelm Leibniz*: Both Newton and Leibniz developed calculus independently. Newton formulated his version in the 1660s but didn't publish it immediately. Leibniz began his work on calculus in the 1670s and published his findings in the late 17th century. This led to a prolonged dispute over who first invented calculus.
- *Robert Hooke*: Hooke proposed ideas about planetary motion and gravitation. In the 1670s, he suggested that planets are attracted to the Sun by a force inversely proportional to the square of their distance. This concept influenced Newton's formulation of the law of universal gravitation, though the two scientists had intense arguments over the credit for this discovery.
- *James Gregory*: A Scottish mathematician, Gregory made significant contributions to calculus and series expansions. He discovered the series expansion for the inverse tangent function, known as Gregory's series, and worked on methods of calculating areas under curves, which are fundamental aspects of calculus.
These instances highlight the phenomenon of multiple discovery, where different scientists independently arrive at similar conclusions around the same time.