The story of Newton's apple first appears in Voltaire's Elements de la Philosophie de Newton, published in 1738, long after the great English mathematician had died and 73 years from the time the disputed apple fell. Voltaire admired Sir Isaac and his theories tremendously and offered a clear, insightful interpretation of his teachings. But his only source for the apple story was Sir Isaac's niece, Catherine Barton Conduitt, who had married one of her uncle's closest associates. She and her husband lived with and kept house for Newton in his declining years.

Another bit of evidence, one that is taken quite seriously by the story's adherents, is Rev. William Stukely's biography of Newton, written in 1752 though unpublished, mysteriously, until 1936, Stukely, a physician, cleric, and prominent antiquarian, wrote that he was once enjoying afternoon tea with Sir Isaac amid the Woolsthorpe apple trees when the mathematician reminisced that "he was just in the same situation as, when, formerly, the notion of gravitation came into his mind. It was occasioned by the fall of an apple, as he sat in contemplative mood.

The story about Sir Isaac Newton discovering gravity when an apple fell on his head as he was sitting under an apple tree is an invention.

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This is an exaggeration of Newton's own tale about sitting by the window of his home (Woolsthorpe Manor) and watching an apple fall from a tree. However it is now generally considered that even this story was invented by him in his later life, to try to show how clever he was at drawing inspiration from everyday events.

Decades after Newton's death in 1727, the French philosopher Voltaire put it in a book, claiming that Newton's niece, Catherine Conduitt, believed it to be true. If it had been, Newton would probably have made some kind of reference to it during his lifetime.

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