Rodney Stark, in his paper Atheism, faith, and the social scientific study of religion (read the full text in google books) outlines an interesting phenomenon from Enlightenment thinkers, still observed in current popular discourse:

The social “scientific” study of religion originated in atheism and the basic theses pursued today, especially by psychologists and anthropologists, are little changed since they were first proposed by militant opponents of religion in the seventeenth and early eighteenth century. In this essay I trace these links from major scholar to major scholar across the centuries. I then examine the remarkable irony that the recent emergence of a truly scientific approach to religion was accomplished mainly by an influx of “believers”;. I sketch why and how this happened before turning to an assessment of the persistence of atheistic biases. I conclude with suggestions about how a truly scientific study of religion can be pursued by both believers and unbelievers, if not by fanatics of either stripe.

Until quite recently there was very little science in the social scientific study of religion. As a child of the “Enlightenment,” social science began with the conviction that religion was not only false but wicked and best gotten rid of as soon as possible. Of course, there was nothing new about atheism: many ancient Greek philosophers rejected the gods, as did various schools of Indian and Chinese philosophy. Indeed, according to Clifford Geertz, atheists exist in preliterate and “primitive” societies, making it likely that there were atheists even in Neanderthal times.

What Thomas Hobbes and his friends began more than three centuries ago was, however, something quite original. Not only were they the first to use the tools of a developing social science to attack religion, but they tried to make a religion out of their science—an intellectual tradition that reached full flower more than three centuries later in Carl Sagan’s recent popularizations, in which the “Cosmos” is the proper object of awe and “Nature” is always capitalized. In one paragraph of his enormously influential work Leviathan, Hobbes dismissed all religion as “credulity,” “ignorance,” and “lies,” explaining that although the gods exist only in the minds of believers, and are but “creatures of their own fancy,” humans “stand in awe of their own imaginations”. Two centuries later there had been a considerable evolution in academic jargon, as demonstrated by the German philosopher Ludwig von Feuerbach when he made a similar claim
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