Birthday of Georg Cantor (1845)

Creator of set theory and the mathematics of infinity. Cantor proved there are different sizes of infinity — that the infinity of real numbers is strictly larger than the infinity of integers, using his diagonal argument. This was so radical that his former teacher Leopold Kronecker called him a 'corrupter of youth.' The stress of constant attack drove Cantor to repeated mental breakdowns. Today his work is considered the foundation of modern mathematics, and Hilbert famously declared that no one would expel mathematicians from the paradise Cantor had created.