I meant something like the difference between:

Bob says: "There will be an assassination..." Player's notebook is automatically filled with this information. The player can assign expected probability. Bob says: "Alice told me so" Player's notebook is automatically filled with this information marked as evidence for the previous claim. The probability assigned to this being true will automatically update the assassination claim.

Or what I was considering yesterday:

Bob says: "There will be an assassination..." Player manually writes this into his notebook. Bob says: "Alice told me so" Player manually writes this into his notebook and manually marks it as evidence for the previous claim. The automatic updating would still happen after this has been done. Alternatively, the player might just go ahead and write in a conjunction for "Alice told me so" & "Alice knows what she is talking about" & "Alice tells the truth" instead.

Pro: Learning to extract facts from statements seems like a useful skill to teach. Con: Without letting the game know about the intended meaning of the facts, it would be very hard for it to find and correct faulty reasoning. It might also turn into too much bookkeeping for the player.

I'm leaning more to a middle ground now, were the game presents all facts that are part of a statement, but it is still up to you to connect them to the right place in the graph. We'd have to experiment to find what actually works of course.

I also meant that if we make it a good enough tool, maybe it would be valuable to use entirely independent from the game. If that should be a goal, it would need to be carefully designed for. This will likely introduce conflicting requirements though, so may not be worth it.

I probably won't finish up something demoable today either. I've mostly just been brainstorming on mechanics and the architecture to support them.

Some more random notes from the prototyping:

• There are beliefs and correlations between beliefs.
• Beliefs are entered with a prior for how likely they are without any of the given correlations (prior).
• Correlations are entered with a belief as cause and one as effect and values for probabilityOfEffectGivenCause + probabilityOfEffectGivenNotCause
• Conjunctions and disjunctions can be expressed as special cases of beliefs.
• The full complexity should not be introduced all at once.
• To guide giving probabilities they could be converted to frequencies in time or space. ("So with no evidence, you believe there would be an assasination like this every week?"; "[...]right this hour in one city in the country")
• My biggest problem is that I have no idea how to actually score a player if he gets to come up with his own probabilities in a fictional world. Maybe the game needs to have some way of explicitly finding out the "right" values for some priors and correlations.