I Can Calculate The Motion Of

This remark is connected to Newton's financial losses in the South Sea Bubble of 1720, one of the first major speculative crashes in financial history. The earliest recorded version, traceable to notes by the literary scholar Joseph Spence (pre-1768 and published 1820), has Lord Radnor reporting that Newton said he "could not calculate the madness of the people" — a simpler phrasing that later acquired the contrast with "the motions of heavenly bodies." Despite the embellishment, Newton did invest heavily in the South Sea Company and suffered substantial losses, lending the sentiment a plausible historical basis.