Light isn't good, and Dark isn't bad. I would think that's obvious to many people here because this web community (at given times) is a great representation of that principle. There are many people in the Dark aspect that exibit beautiful compassion and warmth. There are Lightsiders who can be just plain volatile and aggressive. So what are these two "opposites?" Many years ago, when I was but a wee Padawan here at the FA, I was known to say, "Love, Light, and Truth are all the same thing," without really knowing what that meant. It's always been true for me, but I just didn't know why or how. Well, how it works is like this: Love (Light/God/etc.) is simply the principle of unification. Two things become One. Love isn't affection, attachment, liking a whole lot, passionate emotion, or anything other than just two or more things becoming One through unification. All of those concepts I listed can come out of Love, but they are not love. It's like smoke and fire. You can't have smoke without fire, but smoke is obviously not fire. It's a buyproduct.
If Light/Love is the principle of unification, it can't help but be Truth, because unity, Oneness, no-separation is the ultimate truth. The Force is all there is. The separate, personalized Self isn't real, or at least, isn't ultimately real. It's only relatively real. Then you die. And the story's over. That's kind of scary (and by kind of scary, I mean absolutely terrifying) because there's a part of us that really wants to pump up the personalized Self and hold onto it. There is a HUGE energy in me that wants to make a big deal about the things that happened to me in the past and focus a lot of energy on what I either fear or hope will happen in the future. It doesn't like to spend a lot of energy on the present, but that's another post all together. When you start to see through the eyes of Light (One "Self"), you truly begin to express Love that has no motive, bounds, or desire. When you see through the eyes of the ego, that's when you truly express states of anxiety, fear, and judgment.
Darkness. Beyond the villification, Darkness is just the principle of separation. Two or more. This and that. Right and wrong. That spirit is incredibly helpful in one regard, because this phenominal world is based on it. The physical universe is made up of all these fragments. We know hot because of cold and so forth. That's pretty cool! I can just get lost in how many billions of actions go on inside my body to make it work. It's incredibly cool and incredibly awe-inspiring. And who do I have to thank for that? Satan.
Yeah, really. That dude. Again, outside the villification, Satan is just the spirit of separation. Some aspects of separation are cool to experience. Most aspects of separation cause pain and suffering. And this makes perfect sense, because how else could you suffer if you didn't believe you were a small, individuated, fragment? You would be crazy NOT to feel anxious if you identified with the "Little Me" with its dramatic story of triumphs and failures. There's only one catch: who moves Satan?
God.
Light moves Darkness. This isn't because the good guys always win. This is because Light is the principle of unification, which causes the end of separation. Separation is a concept that is contained WITHIN unification. Also, unity doesn't need another thing to exist in order to be. Because it's just One. Separation needs other stuff to define its existence, otherwise there would be no separation! There needs to be hot AND cold in order to have separation. But unity just looks at it and goes, "It's all water." End of separation.
So what does this say about fighting Darkness? It says that you can't actually fight Darkness. Because in order to fight something, you need there to be two or more things. I have to be over here, and the wrong thing needs to be over there in order for the two of us to fight. In that situation, you're bringing separation to the principle of separation! Of course you're going to lose. You're playing on its turf. Sometimes, Darkness can be tricky and pretend like it's Light. It can rise up in you through righteousness and trick you into believing you're right. "You're right! And you should do something about all this wrong going on!" However, the only way you can be right is if something else is wrong. More separation. You've given in again.
How do you get Darkness to go when it's no longer working for you? You love it. Unify it. What does that mean? You see yourself in it. That's all unity really is: to see your Self - not your personality, not your mind, not your sense of humor - your Self in other forms of life.