This book offers an original account of an ancient, alternative form of 'negative' reason which stands in antithesis to its modern instrumental form which has dominated thinking about the pursuit of human development since the Enlightenment. It advances arguments for the recovery of such reason as a spiritual and therapeutic way of life and demonstrates that it is impossible to fully appreciate the Christian apophatic tradition without investigating the intricacies of its philosophical heritage. The aim of this discussion is the retrieval and rediscovery of invaluable insights from ancient philosophy in the universal pursuit of happiness. The book's re-appropriation of the 'negative' philosophical and theological articulation of the pursuit of eudaimonia offers to redirect those living in the twenty-first century towards the significance of the Christian apophatic ascent and in so doing to assist them in uncapping the wellsprings of human passion, desire and happiness.