'Those who believe that they infallibly listen to a divine command, have nothing else to do but obey it. Those who are the mere creatures of instinct press on without misgiving. And those who suppose they follow their manifest destiny, go forward come what may! But as for us, while we know that we must go our way, we have to learn which way is right and safe. If we pursue the course we trod in former years, whither will it lead us? Where has it led us? What reason have we to believe that it is the way of wisdom and the path of duty?'
From Go Forward, by Russell Lant Carpenter