As I have followed the course of the thread, it seems to me that no one is denying that someone can set out to use plausibility as a heuristic.
I think the concern is more along the lines of it not yielding a unique outcome.
Sometimes the analysis yields a unique outcome, and sometimes it doesn’t. It depends on the circumstances, the character’s capabilities, and what is being attempted. That’s the nature of thinking about possible futures, even when that future is just the next moment. In my experience, outcomes fall into three levels:
- What is most likely?
- What is probable?
- What is possible but not likely?
For example:
A few sessions ago, the players sent a letter to the Baron of Westtower asking for permission to speak on behalf of a merchant guild. The Baron never replied. Now the players are returning to Westtower and want to know how their request was received.
This is where I look at the three levels of possible futures:
- Most Likely: The letter was filed away and ignored. The Baron receives dozens of similar requests and had no reason to prioritize this one. This reflects the normal, indifferent function of a noble’s staff.
- Probable: The letter reached the Baron’s steward, who remembered the party from a previous visit. He passed it along with a note vouching for them, which means they’re now on a list of names known to the Baron’s court, even if no formal response was given.
- Probable: The letter was received but misfiled or delayed due to a backlog in the Baron’s scribal office. A lower-ranked scribe recently rediscovered it and added it to the next batch of matters for review.
- Probable: The Baron sent word to the local guildmaster to ask for his opinion of the group.
- Possible: The Baron read the letter personally and found it curious. He’s been watching their movements through informants ever since, considering how he might use them. That’s a deeper, more dramatic thread, but still grounded in earlier interactions and Westtower’s political logic.
- Possible: The letter never reached the Baron because it was intercepted by a rival faction within his court.
- Possible: The Baron saw the letter as an opportunity to pressure the merchant guild. He never responded, but summoned the guildmaster and used the letter as leverage.
I’d appreciate if we didn’t debate the exact definitions of “likely,” “probable,” and “possible.” The precise terminology isn’t important. What matters is that, in a given situation, there’s often (but not always) an outcome that stands out as most likely. Then there are alternatives that have a reasonable chance of occurring. And finally, there are the less likely but still possible outcomes. Those are what I’m weighing when I consider plausibility.
The above scenario is deliberately simple to illustrate the point, any number of permutations could be developed. But regardless of the complexity, you can still identify tiers of plausibility and make decisions accordingly.
And I don't think your examples really speak to that concern. Counterfactual history, for instance, generates multiple inconsistent conjectures.
Regarding counterfactuals: alternate history writers have dealt with the problem of multiple plausible outcomes for decades. The key isn’t whether there’s only
one valid outcome, it’s that any outcome chosen follows a plausible chain of cause and effect from the point of divergence. That’s the same principle I apply in my campaigns. I work within a bounded range of plausible results, constrained by what’s already true in the world, not just what’s dramatic or interesting. When several outcomes are plausible, I may consider what best aligns with the goals or motivations of the characters involved.
As I stated earlier, relying solely on dice rolls, or solely on judgment calls, hasn’t created the sense of a living world in my games. Based on player feedback, a mix of both does.
And JRRT himself, when adding bits to Middle Earth, kept changing his mind.
I wasn’t referring to Tolkien’s evolving drafts. I was talking about the designers of
Adventures in Middle-earth and
The One Ring. They work within the logic and tone of Middle-earth to produce new material that still feels like it belongs. That’s what I mean by plausibility in an RPG context, it’s not about inventing the world as you go, it’s about extending what’s already there in a consistent way.