Walter Charleton, a physician and a Christian believer, was on the first advocates of physico-theology that started on a large scale at the end of the 17 ^th century and flourished in the 18th century. In his battle with the English deism and atheism, he used the arguments of the orderliness of nature to prove the existence of God. He was one of few authors trying to reconcile atomism with Christian theology. He also grappled with the problem of the immortality of the soul supporting at one point Gassendi’s idea that humans have two souls, sensitive and rational.