In the second part of this book we saw evidence of the reaction to late nineteenth and early twentieth century philosophy where religious thought had been undertaken in many cases by philosophers and theologians influenced by the Hegel or Kant. Philosophers and theologians alike turned from the ideal and the metaphysical to the real and the empirical, and the expectation that either God or human persons would bring about the perfection of civilization was called into question by events that threatened life on the globe. In many cases, however, science gained the upper hand in defining experience and knowledge and theologians often cooperated in removing religion from the realm of human experience and the knowable. Perhaps it should not be surprising that some theologians blamed what appeared to be the collapse of western civilization upon a loss of the transcendence of God, and looked to a wholly transcendent God for the salvation of humankind. These developments led eventually to a breakdown of the close relationship between philosophy and theology that had characterized much western thinking in the early part of the century. The spirit of the time is captured well in H.J. Paton's Gifford Lectures (1949/1950) in which he challenges what he calls a theological and a philosophical veto of all natural knowledge of God. The theological veto is associated in particular with Karl Barth, and the so-called positivists of revelation, and the philosophical veto is associated in particular with A.J. Ayer and the logical positivists, whose work will be discussed in this part of the book.