"Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so."[2]
Simple: People are almost the only animals that can learn from what others do. Another interesting thing about people is that they do not seem to want to.
What it means: People have the ability to make great changes, but usually they are not willing to.
"I don't believe it. Prove it to me and I still won't believe it."[3]
Simple: I do not believe what you say. Show me that it must be true and I will still continue not believing it.