Alignment is a hot topic when it comes to D&D. Some people love it, some people hate it, and everyone has their reasons.
What I'd like to talk about here is actual facts regarding alignment. What alignment really is, and what it is not.
For purposes of this discussion, any and all claims made about alignment, if presented as a “fact” must be backed up with evidence. This is how logic and debate rules work. If you make a claim, you either back it up, or cede the point. If someone you are arguing with says “prove your claim”, don't get butthurt and whine that “I don't have to” or “you don't have the right to make demands of me”, because that is incorrect. In debate, your opponent ABSOLUTELY has the right to ask that you back up your claims.
Because of this emphasis on what is fact and what is not, your own personal experiences and anecdotal references do not constitute valid fact. Alignment gets misused and abused, by players and Dms alike, all the time. That has no bearing on the facts of alignment. Since D&D is frequently houseruled, and there is no objective manner in which to cover and account for every given houserule, only RAW (Rules As Written) is considered valid fact.
I fully expect that 3.5e, as the most recent edition to have the “9 alignment grid” and concrete alignment mechanics, will be the most discussed system of alignment and alignment mechanics. If you are discussing a different edition, make that clear in your points, please.
I hear alignment detractors all the time cite this or that reason why alignment limits them, but the truth is this: Nothing about alignment limits one's creativity, or the actions of one's character. The RAW explicitly state that alignment is NOT a straightjacket (3.5e PHB page 103). Therefore, any statement to the contrary is objectively false.
Another point alignment detractors like to focus on is the claim that “alignment cannot work because morality and ethics are subjective”. While it is true in the real world that morality and ethics are subjective (after all, what one culture perceives as good, another might view as abominable), in D&D there is an objective scale. The 3.5e RAW, for example state : “Good and Evil are not philosophical concepts in the D&D world. They are the forces that define the cosmos.” (page 103). Dungeons and Dragons is FANTASY, and because it is so, things like objective values of Good and Evil may exist. While an individual may believe that his/her actions are justified, or “for the greater good”, there is an objective scale by which that individual is judged. That person's place on that scale is his or her alignment. The RAW presents the definitions of Good/Evil/Law/Chaos, and while an individual DM might impose his/her own moral/ethical values on that in his/her ruling on the matter, if that ruling is not compatible with RAW, then it is a houserule.
Others say “when you use alignment, you are playing an alignment, and not a personality”. The RAW also state that each alignment covers a broad range of personality types and personal philosophies (3.5e PHB, pg 103), and that just because someone has a greed streak, or a short temper, does not mean that said person is not Lawful Good.
One of my main points is this: ALIGNMENT IS NOT AN ABSOLUTE BAROMETER OF ACTION OR AFFILIATION. A Chaotic person is not obliged to break laws or disobey authority. An Evil person is not incapable of selfless action. Being Lawful may or may not have anything at all to do with civil law or authority. Being Good does not mean never doing things to your own advantage.
Have DMs all over the world forced a PC's action because “your alignment is x, you can't do that”? Of course, you hear about it all the time. But that kind of DM overbearingness is not supported by RAW, and is therefore a houserule. Have players been disruptive or combatative to the other members of their party and used alignment as an excuse for bad behavior? Certainly, but nothing about alignment RAW encourages or even allows that. The fact is, that those kinds of DMs and players are the problem. You could run a game without alignment, and a DM could still find a way to try and railroad you, or force your character's actions. A player in a game without alignment could write up a detailed character background and personality, and still act contrary to it, and be just as disruptive.
In 100% of the examples I have ever been presented with about why alignment is bad, the issue is a player or DM deviating from RAW. Not once has an alignment detractor presented a situation that can show, objectively, that alignment, when properly used in accordance with RAW, has caused problems in their games.
People are certainly entitled to their opinions. If you don't like alignment, don't use it. Far be it from me to tell you you're “doing it wrong”. D&D is a game that thrives on individuality and customization. If you prefer to run a game and throw alignment out the window, and you and your players have fun playing, more power to you. But don't claim falsehoods about what alignment is and is not. Your opinion, while valid for you, does not hold objective weight if you can't support your points with direct quotes from RAW.
I absolutely welcome the alignment detractors to post here if they will support their points with actual facts taken directly from RAW. I love a good debate. But showing up and posting short, blanket statements such as “alignment is crap, it should be thrown out of the game, and no one should use it ever” is trolling, and I will report your post as such.
Also, no personal attacks. If I catch anyone on either side of the fence on this argument making ad hominem attacks, I will report your post myself. To that point, if someone attacks your argument, be an adult about it, and don't complain that they are attacking YOU.