In 1951, Pope Pius XII gave a long speech with the unequivocal title ‘The proofs for the existence of God in the light of modern natural science’, dealing with the relationship between modern science, Thomism and theology. The event was widely reported in the British press partly because the only living scientist quoted in that discourse was the Edinburgh emeritus professor of mathematics and convert to Catholicism, Edmund T. Whittaker (1873–1956), who was, in the 1930s and 1940s, producing his own corpus on the then-popular subject of science and religion. In this article, using the vast and unexplored correspondence between Whittaker and his son, the mathematician John M. Whittaker (1905–1984), I shall explore his thoughts and popular works, in which he mixed modern physics and mathematics, philosophy, apologetics, and theology. Whittaker is well known among historians of science for his A history of the theories of aether and electricity , the work of a hard-working, self-trained history aficionado. Similarly, after his conversion (in 1930, at the age of 57), Whittaker started reading and forming his own views around the official philosophy of the Catholic Church, Thomism. The core idea with which he justified his conversion and which would be the backbone of his speculations on natural theology was ‘sacramentality’. With it, he thought he could bridge the gap between mathematics, modern physics, and religion, and all with a sui generis embrace of Thomism.