Life in ancient and medieval times - teeming with poverty, disease, early death, cruelty and war - was hardly enviable. The concern of the Enlightenment was to alter this. Rather than a world of countless suffering serfs and a few princes living in luxury off of everyone else's labor, a great humanitarian endeavor was undertaken to elevate suffering humanity and provide a good life for all. The value of this endeavor is undeniable. But the cost has...