Frances Wright

If we bring not the good courage of minds covetous of truth, and truth only, prepared to hear all things, and decide upon all things, according to evidence, we should do more wisely to sit down contented in ignorance, than to bestir ourselves only to reap disappointment.

Surely it is time to examine into the meaning of words and the nature of things, and to arrive at simple facts, not received upon the dictum of learned authorities, but upon attentive personal observation of what is passing around us.

Even though we don't always realize it, as the day goes on, we have increased difficulty exerting self-control and focusing on our work. As self-control wears out, we feel tired and find tasks to be more difficult, and our mood sours.