In knowledge of human affairs, we should never allow our minds to be enslaved by others by subjecting ourselves to their whims. We must maintain freedom of thought, and never accept anything of purely human authority into our heads. When we are presented with a diversity of opinions, we must choose, if we can; if we cannot, we must remain in doubt.
Consider the wheelbarrow. It may lack the grace of an airplane, the speed of an automobile, the initial capacity of a freight car, but its humble wheel marked out the path of what civilization we still have.