To me it seems not unreasonable to find a re-enforcement of...

To me it seems not unreasonable to find a re-enforcement of optimism, a renewal of courage and hope, in the modern theory that man has mounted to what he is from the lowest step of potentiality, through toilsome grades of ever-expanding existence, even thought it have been by a spiral stairway, mainly dark or dusty, with loop-holes at long intervals only, and these granting but a narrow and one-sided view.