Many, perhaps even most MU*s use a stats and dice system in roleplay. This introduces an element of chance — even the player doesn't know if their character will succeed or not — and also serves to determine how much damage a character takes in combat and confrontation scenes, preventing any cases of 'I don't want my character to get hurt, so all your attacks miss.'
That said, stats have their downside as well. Some things are very difficult to translate into a simple set of numbers, especially when dealing with a vast range of superhuman abilities. The numbers never capture the full breadth and depth of a character, unless the system is convoluted and complicated — and then it becomes a hindrance to storytelling rather than an aid.
As String Theory MUX focuses on storytelling and roleplay, the staff have chosen not to incorporate any form of stats system on this MUX. Instead, the rule of thumb during scenes is ICA=ICC:
In Character Actions lead to In Character Consequences
While many characters on String Theory have supernatural abilities, remember that the game is about otherwise normal people making their way through life in what might well be the universe next door. This means that actions have much the same consequences as they would in the real world. If your character picks a fight with someone, or otherwise sets them off, your character is likely to get hurt. If your character is present for a gunfight and doesn't keep their head down, they're apt to get hit by a stray shot. If they rob a jewelry store or kill someone, the cops will be out looking for them.
The player always has the right to not roleplay. By choosing to take part in a scene, you implicitly agree to accept the logical and sensible consequences of events in that scene.
With this rule comes responsibility. When a player is putting their character in serious danger, it is the responsibility of other players in the scene to make sure they are aware of what might happen — namely, in events where serious injury or death is probable for the character. If said player suddenly realizes the hot water is much deeper than they thought and wants to avoid the worst of those consequences, it is the responsibility of everyone else in the scene to try and find a compromise. (Which makes it a good idea to do the 'you know you're in trouble, right?' warning as early as possible…) If the players involved cannot come to a mutual compromise, staff will step in, take all factors into consideration and make a decision for them.
It is also the responsibility of players not to use this caveat as a loophole, playing with fire and then refusing to accept the burns. A character cannot be killed or seriously injured without the explicit permission of their player (unless staff is called into mediate and decides otherwise), but abuse of this rule will be reprimanded by staff; repeated instances may be a bannable offense.