This symbol had a lot of different interpretations, depending on who interprets it.
To me, it is a representation of good and bad, light and dark, male and female. I believe that you cant have one without the other. Its just not possible. nothing is completely bad, or evil, just as nothing is completely good. In every bad act, there is some goodness intended. In every good act, something bad can be found. It could be selfishness, or the desire for someone to return the favor. Doing something in hopes of something in return isn’t truly just an act of kindness. Its the same with bad actions. when someone does something that is considered bad, they might think it its going to help. There are many different possibilities.
You’re probably wondering about the male and female thing I said earlier. If you’ve taken a health class, or payed attention in one, you probably know that males have small amounts of the female hormone, estrogen, in them. Just like girls have some testosterone.
This symbol is usually thought of as a Chinese or Asian symbol. While this is true, many different Pagan religions use it. It is a perfect visual explanation of how good and evil intertwine. and how nothing in purely black or white. It is also perfectly balanced, which will bring peace to a very spiritual person.
Enjoy some peace!