Monday, September 12, 2011
Divination by PCs and NPCs are going to yield an answer. The accuracy of the answer is modified by the PC's PSI score, but the base 'chance' of correctly parsing the information is largely a function of the sort of question being asked:
VAGUE (+75%): 'Which direction should we travel today?' -- This sort of broad answer does nothing to define the safety of the course pointed, and the Referee is not in much danger of invoking disbelief in the validity of such a broad question.
DEFINED (+50%): 'Is the river route safer than the high pass?' -- This is still a relatively open answer, and the Ref can answer as truthfully as would be apparent to a neutral observer. If there is much more danger in one portion of the one route, it will register as the more dangerous, regardless of how short a span the danger may be, so long as the likelihood of encountering it is great (passing through its lair, for instance). "You will find grave danger in the lowlands, but the pass is treacherous still.", is an honest but minimally-limiting answer.
FOCUSED (+33%): 'Does Yjavella truly despise me?' -- These answers are more correct the greater the person knows the other person/force/group. "Yes, but her love remains undiminished, leaving her in terrible despair." and "No, but her grief is so great that you could lose her if you press the matter." and "Her wroth is great and love is like a great bitterness, yours most of all." are all equally valid, although each flavours the reader's/hearer's perception, and this truth can cause further complication if acted upon precipitously.
SPECIFIC (+25%): 'Is my pursuer around the next corner?' -- These sorts of questions and their answers become a bit quantum, with the boxed cat being the validity from the point of questioning until the point of observation. "Yes." could be true, but by the time the supplicant peers around the corner with pistol, the beast is gone. Mutations that affect the accuracy of the forecast (precognition, ESP, etc.) should be thought of as a more sophisticated weather forecasting array -- its answers may be true in part, in a span of time, not observed or experienced by everyone in a given area. After a fashion, this is like the 'no rain today in the metro area' is true for most of the viewing area, but a few folks are still caught unprepared in a downpour.
PRECISE (+16%): 'Will flipping the switch spell our doom?' -- Either a yes or no answer, although the results of the switch flip could still result in most of the party's death from injuries although they escape from utter calamity. If even one of those present when asked survive, then the 'no' answer will still be true.
COMPLETE (+5%): 'Is this, out of the thousands here, the correct gem?' -- The Referee should be prepared to divulge the accurate answer regardless, if such precise answers are going to be allowed in the first place.
Asking questions of the same order of magnitude halve the interpretation chance each time if asked within an Hour. Asking the most exacting question is then best performed under the most favourable conditions, with the best Utilities, only once, while a slew of vague questions throughout a day could be performed with some success. Analysis-Paralysis can derail any party relying upon divination instead of action, but should be granted as it permits many Encounter Checks, and increases the likelihood of attracting Psychic or Magical creatures.
Modifiers from Utilities (Circlets, ancestral ritual tools, a psychic computer, etc.) increase the percentage of correct interpretation based upon their power, and may provide multiple simultaneous attempts with only the best result chosen, or some other bonus not listed.
Time and conducive environment (hours and a circle of willing assistants, for instance) modify the accuracy of interpretation upwards or downwards, as appropriate.
Illness, injury, emotional upset (such as personal stakes in the answer) will negatively modify the attempt by a variable amount based upon its intensity.
The point of all the preceding is that divination by a PC or NPC need not violate perceived autonomous intent nor railroad (or detour an intentional railroading) the PCs into the determined course of events.
Arcane Skill Ranks are roughly +5% bonus to the accuracy, but also allow for knowledge of Utilities (tome, pendulum, incense, etc.) that may aid in accurate interpretation.
D&D type games would likely use Wisdom as the basis, with Caster Level substituted for Arcane Skill Ranks.
--I have framed the % as a 'roll-high', because that is how I roll.