The full quotation is:
"Once I knew the depth where no hope was, and darkness lay on the face of all things. Then love came and set my soul free. Once I knew only darkness and stillness. Now I know hope and joy. Once I fretted and beat myself against the wall that shut me in. Now I rejoice in the consciousness that I can think, act and attain heaven. My life was without past or future; death, the pessimist would say, "a consummation devoutly to be wished." But a little word from the fingers of another fell into my hand that clutched at emptiness, and my heart leaped to the rapture of living. Night fled before the day of thought, and love and joy and hope came up in a passion of obedience to knowledge. Can anyone who escaped such captivity, who has felt the thrill and glory of freedom, be a pessimist?"