Why did Alfred North Whitehead give up his theological library?

Alfred North Whitehead sold his theological library and abandoned his religious practice after a period of intense study regarding the tenets of the Roman Catholic Church.1

Having been raised in a family deeply rooted in the Church of England, Whitehead spent approximately eight years reading extensively on theology under the influence of John Cardinal Newman. Following this period of investigation, he moved toward agnosticism, a stance he maintained for the remainder of his life, though he never again formally joined any church.1