Unpredictable Random Number Generator: Ceremonial Magic

[malloyd]

Originally Posted by evileeyore

If this were true, then one could set up a lottery system based on the outcomes of Ceremonial Magic castings and thus this lottery would also impervious to Divination magic.

Of course once you do, it quickly becomes impossible to predict *anything*, because any future event that depended on the actions of anyone who might have won or lost that lottery is now unpredictable....

Useful future divination is exactly like time travel - once you allow them cause and effect necessarily break down and logic no longer works in this universe (and never did, because time travel). You can apply patches to make it appear more logical, but the flaw is ultimately still there *somewhere* even if you aren't able to find it.

Since the point of divination is to allow you to do stuff to change the predicted future (it's not particularly useful if you can't), the simplest "fix" that averts a lot of causality issues is to assume anything genuinely random is rerandomized as soon as you do *anything*. You can predict the outcome of the lottery and be right, right up until you attempt to buy a ticket, tell anybody the result, or attend the drawing, at which point you've changed the future. Divination becomes useful only to the extent it reveals future things that are already partly deterministic, but which you didn't already how.

In this case if you can buy tickets and still win reliably, you now know the lottery is rigged in some way, but apparently not one based on correct information about who bought what tickets. And whoever did rig the lottery is probably now angry with you for stealing part of the money they were planned to steal.

[Boomerang]

If I am running a game with magic I don’t worry if things make logical sense only whether a PC is gaining an advantage beyond what their character point expenditure should allow.

So if the character spent far more points on divination abilities to win the lottery than they would have had to spend on wealth levels to get the same benefit then I will allow accurate predictions of lottery numbers. I’m with Robert Heinlein on this one: there ain’t no such thing as a free lunch (TANSTAAFL).