In the past two decades, the anti-religious movement known as New Atheism has been working to define a scientific basis for opposing religion and its influence in public affairs. New Atheist thought on religion is rooted in scientism and a narrative of progress and Enlightenment that refers to ideas derived from evolutionary biology for its authority. A notable feature of this approach is the New Atheism’s critique of the social sciences, which it dismisses as relativistic and seeks to replace with evolutionary psychology and neuroscience. This chapter examines the New Atheism’s position in terms of an historical division within atheist thought between approaches to religion that are grounded in the natural sciences and the social sciences, and argues that contemporary atheism should be understood primarily as a political project to advance the authority of an ideological vision of ‘true’ science and its representative experts. While typically understood as a response to religious fundamentalism, the New Atheism is as much a reaction to a perceived weakening of universalistic standards of knowledge and morality in an increasingly pluralistic western cultural milieu. Through a reading of influential New Atheist texts in relation to the historical development of modern atheism, the chapter examines the relative decline in importance of the social sciences in popular atheist discourse. This decline is a result of the evolving politics of contemporary atheism, which, in some major forms, has drifted away from its roots in progressive social justice movements and ideologies toward a more libertarian position.