ght should be … adherent to a Newtonian worldview, who used Fresnel’s theory to show it led to absurd conclusions. In particular, Poisson showed that if you passed a beam of monochromatic light around a spherical obstacle, you wouldn’t get a bright ring with a solid, circular shadow within it, but instead there would be a bright, luminous point directly in the shadow’s center. Clearly, Poisson argued, this is absurd, and Fresnel’s wave theory of light should be rejected.