But whatever be the risk of corruption from intercourse with the world around, such a risk must be encountered if a great idea is duly to be understood, and much more if it is to be fully exhibited. It is elicited and expanded by trial, and battles into perfection and supremacy. Nor does it escape the collision of opinion even in its earlier years, nor does it remain truer to itself, and with a better claim to be considered one and the same, though externally protected from vicissitude and change. It is indeed sometimes said that the stream is clearest near the spring. Whatever use may fairly be made of this image, it does not apply to the history of a philosophy or belief, which on the contrary is more equable, and purer, and stronger, when its bed has become deep, and broad, and full. It necessarily rises out of an existing state of things, and for a time savours of the soil. Its vital element needs disengaging from what is foreign and temporary, and is employed in efforts after freedom which become wore vigorous and hopeful as its years increase. Its beginnings are no measure of its capabilities, nor of its scope. At first no one knows what it is, or what it is worth. It remains perhaps for a time quiescent; it tries, as it were, its limbs, and proves the ground under it, and feels its way. From time to time it makes essays which fail, and are in consequence abandoned. It seems in suspense which way to go; it wavers, and at length strikes out in one definite direction. In time it enters upon strange territory; points of controversy alter their bearing; parties rise and around it; dangers and hopes appear in new relations; and old principles reappear under new forms. It changes with them in order to remain the same. In a higher world it is otherwise, but here below to live is to change, and to be perfect is to have changed often. – from Essay on the Development of Christian Doctrine (1845)