John Strutt, 3rd Baron Rayleigh Quote

Without encroaching upon grounds appertaining to the theologian and the philosopher, the domain of natural sciences is surely broad enough to satisfy the wildest ambition of its devotees. In other departments of human life and interest, true progress is rather an article of faith than a rational belief; but in science a retrograde movements is, from the nature of the case, almost impossible. Increasing knowledge brings with it increasing power, and great as are the triumphs of the present century, we may well believe that they are but a foretaste of what discovery and invention have yet in store for mankind. … The work may be hard, and the discipline severe; but the interest never fails, and great is the privilege of achievement.

Address to the British Association in Montreal (1884)