Opposites

When I read chapter 2 of the Tao Te Ching, there was a phrase which got my attention: "Under heaven all can see beauty as beauty only because there is ugliness.
All can know good as good only because there is evil."(Chapter 2)
What this says is that the reason why something is what it is, is because of its opposite. For example there's evil because there's good. We know when someone looks ugly because we know when someone looks pretty. We know when something is hard because we know when something is easy. The reason why things are what they are is because of their opposites. It's because we have something to compare them with. If there weren't short people, then there wouldn't be tall people. We can tell when someone is tall because we know when someone is short. Opposites make things be what they are.
Things exist because they have opposites. Love exists because there's hate. There's knowledge because there's ignorance. There's intelligence because there's stupidity. There's light because there's darkness. If things didn't have opposites, then they wouldn't exist. Things are what they are because of their opposites. If there weren't opposites to compare things with, then there will be nothing. If it wasn't for the bad things that have happened to us in our lives, we wouldn't have great moments and memories. What makes those moments great are the bad things that have happened to us before. When something happens to us, we know if it is good by comparing it to past events. We know how something is by comparing it to its opposite.