Carl Becker's seminal work, 'The Heavenly City of the Eighteenth-Century Philosophers,' challenges the conventional view of the Enlightenment as a purely rational and secular movement. Becker provocatively argues that the philosophes, despite rejecting traditional religious dogma, constructed their own 'heavenly city' – a new, secular paradise based on reason, progress, and humanity's perfectibility. He contends that their philosophical frameworks, much like the theological systems they critiqued, were founded upon a deep, albeit unconscious, faith in their own constructs. This insightful book reveals the underlying quasi-religious assumptions of 18th-century thought, illuminating the enduring human need for ultimate meaning and purpose, even in an era championing reason over revelation. It remains a cornerstone for understanding the intellectual complexities of the Enlightenment.