ABSTRACT
In search of truth, science has progressed through two stages: the empirical stage and the theoretic stage. At the empirical stage, typically induction by simple enumeration and Mill's five methods of induction are used to arrive at empirical generalizations such as 'Ice floats on water', 'Metal expands when heated', Hooke's law and Boyle's law.1 The theoretic stage came later. In the beginning, the invention of theories was sporadic. Theories came in dribs and drabs. For instance, the ancient Greeks Leucippus and Democritus (c. 420 BC) speculated that matter is made of atoms, moving in a void. Ptolemy (c. 140 AD) proposed his epicycle theory of the planetary system. Theodoric of Freibourg (14th century) suggested that rainbows are the products of rain droplets. Then, in the 17th century, the great Newton launched his theory of gravitation. Henceforth, theories blossomed as wild flowers in spring. Modern history of science is the story of great theories.2
