Among the parameters that ought to shape philosophical inquiry is humanity's developmental status, but it is a missing parameter. The Humility of Reason remedies this deficiency, arguing that in the remedy lie the seeds of a new and fruitful approach to philosophy. J. L. Schellenberg begins the book by contending that, despite our growing technological sophistication, humanity remains at an early stage of development. When we consider the emotional, social, moral, and intellectual growth that we might hope to attain, what we have achieved so far appears, by comparison, rather small. From this early-stage claim arises the early-stage rule—the requirement that we adapt ourselves and our projects to humanity's actual developmental condition—and a new philosophical orientation: stage-sensitivity. Applying stage sensitivity across a wide range of philosophical problems, Schellenberg shows how what initially seems a constraint turns out to be a powerful resource. When we step back and take in the macroscale, we recognize our modest developmental status, but at the same time, a new way forward suggests itself. Some philosophical problems must be scaled to our present capacities; others—more radically—turn out to be stage-defined, requiring entirely new ways of thinking. By attending to these possibilities, The Humility of Reason shows how familiar debates can be clarified, reshaped, and in some cases resolved—offering a striking new vision of philosophical progress.