This seems like Chesterton to me. Good writer, but I take exception to his world view. We should simply doubt that which is warranted to doubt and be confident in that which warrants confidence. If modern people doubt truths more than people used to, perhaps its because those so-called truths aren't so obvious as some people would have you believe.
"But the new humility makes a man doubtful about his aims, which will make him stop working altogether."
This just fundamentally misunderstands what aims are. They can neither be doubted or correct. I can doubt empirically, or epistemologically, but I can't doubt that I want to eat a doughnut or that I want to be healthy or that I want a world with less cruelty in it. It's a waste of time and energy to doubt these things, although I can try to line up all my desires and figure out how they stack up with one another when I try to make plans, the efficacy of which is in the realm of the believable. I can look at other people's actions, try to determine their desires, and decide whether to assist them or interfere with them or fight them, but when I do this its not a cosmic battle about truths. Its just two people acting out on their desires in a shared world.
"But the new humility makes a man doubtful about his aims, which will make him stop working altogether."
This just fundamentally misunderstands what aims are. They can neither be doubted or correct. I can doubt empirically, or epistemologically, but I can't doubt that I want to eat a doughnut or that I want to be healthy or that I want a world with less cruelty in it. It's a waste of time and energy to doubt these things, although I can try to line up all my desires and figure out how they stack up with one another when I try to make plans, the efficacy of which is in the realm of the believable. I can look at other people's actions, try to determine their desires, and decide whether to assist them or interfere with them or fight them, but when I do this its not a cosmic battle about truths. Its just two people acting out on their desires in a shared world.