Question

Newton applied Kepler's data on planetary motion to develop his law of gravitation. What do scientists now call this logical reasoning?

Answer 1

Scientists call this logical reasoning "Inductive reasoning" or "Generalization". It is a form of logical reasonings whereby common properties of specific instances are formulated as general concepts or claims.

Kepler's data and his three empirical laws were such specific instances and the final Newton's law of gravitation is the great example of much more general concept. Newton's law allows to explain and derive not only Kepler's data, but far wider range of experimental evidence.