Why did Linus Pauling object to the idea of quasicrystals?

Linus Pauling’s objection to the existence of quasicrystals was rooted in the long-standing scientific consensus that fivefold symmetry was impossible in crystals, as it could not form a repeating, regular structure.1

Pauling argued that what were being identified as quasicrystals were actually ordinary crystalline materials that had been trapped out of equilibrium. He proposed that these structures were the result of twinning—a type of crystal defect—where unit cells containing icosahedral motifs were attached at specific angles. Because he believed these materials were simply conventional crystals with defects, he famously dismissed the discovery by stating, "There are no quasicrystals, only quasi-scientists."21

While Pauling's twinning model offered a potential explanation for rapidly cooled alloys, it failed to account for quasicrystals that exist in thermodynamic equilibrium. These materials can be grown slowly to achieve perfect long-range order, a level of structural perfection that cannot be explained by twinning.2