Throughout my many debates with people related to the idea of government and authority, a common argument they use is that "the law" is the main, if not only, objective way to determine right and wrong, because it is "officially" written down and accepted by society as the rules that have to be followed. Otherwise, according to them, everyone would believe that they have the right to enforce their own moral code based on their opinions, and there would be fights everywhere (both verbal and physical) about what is right and wrong. There are several flaws with these assertions, the main one being that writing something down and calling it "law" doesn't change whatever was suddenly made law.
For example, whenever I give my definition of morality and specific actions that I consider to be moral or immoral, those I argue with almost always immediately point out that these are just my opinions. However, they completely miss the fact that every law is also just based on individuals' opinions and interests. What if I ran for office and was able to make my views on morality part of "the law"? Are these views all of a sudden objective now, instead of just my opinions? Obviously not; they are still my views, regardless of whether they are called "law" or not. To add, people believing something doesn't make it true. Sometimes beliefs match reality, and sometimes they don't, but reality is independent of what people perceive reality to be, because reality exists outside of our own understanding of it.
Public opinion, or the majority supporting a certain view and wanting it to be law, also doesn't automatically make that view objective. In other words, the number of people believing something doesn't make it any more true or false, not to mention the numerous times societies have changed their opinions on a bunch of different issues ranging from slavery to same sex marriage.
This leads me to my next point: the fact that laws are enforced don't make them objective, correct, or good either. Any idea or view can be upheld using threats of force, including the laws of evil regimes such as Nazi Germany, Stalinist Russia, Mao's China, North Korea and so on. In addition, nothing guarantees that these laws will always be laws, or that they will always be enforced. Laws are repealed or amended all the time, and plenty of laws are ignored at least some of the time.
Now that I've briefly covered the first part of this article about why "the law" isn't objective, I'm going to discuss the next wrong assumption that I mentioned I've heard a lot: without laws, everyone can decide what's right or wrong and act on those beliefs, because there's no "higher authority" telling them otherwise. This is false because there is a "higher authority"; the difference is that it's not a person or group of people creating laws. It's called objective morality, which is based on the non-aggression principle. It is wrong to attack or steal from others because it harms them without justification, and the harm is measurable. Whether someone was physically attacked isn't subjective; it's objective and easy to prove if the incident was recorded, or if there were neutral witnesses. Subsequently, fighting back against an attacker isn't the same as attacking, because it isn't the initiation of force. It is using force or violence in self-defense; the only time using violence is actually justified.
Private property is also objective and measurable since it is the result of the fruits of one's labor, or the voluntary acquisition or trade of something through the mutual agreement to the deal by everyone involved. It is wrong to steal private property, as the thief didn't legitimately earn or acquire the property and is taking it away from someone who has the right to that property.
In short, we don't need "laws" to determine right and wrong, we need principles: specifically the non-aggression and self-ownership principles.