It was neither in the apple nor in any element at the centre of the earth that the law of gravitation was discovered. It was in the mind of Sir Isaac Newton. The falling of the apple gave only a suggestion to Newton and he studied it in his own mind. The rearrangement of previous thoughts in his mind gave birth to the law of gravitation. This unique narration is given by Swami Vivekananda who asserted that knowledge is inherent in mind. “No knowledge comes from outside; it is inside”.
Source : Article in The Statesman by Patranga Basu