Please note that this is just me musing and putting things out there in case anyone has any ideas.
One of the main concerns I have with using syllogisms is that some sort of adjudication is needed to know what sort of content is valid in light of the premises and/or syllogisms. Perhaps the only elegant way to adjudicate validity is to leverage the person’s intuition. Syllogisms already act as a funnel for creativity so this might be enough.
At the same time, a way to validate this intuition when it isn’t strong enough might add to the feeling of certainty some of us seek. What might a process of this kind look like? The only thing that I can think of is explicit rationalization for why something is valid. Basically, justifying to yourself why some content fits the boundaries set by the premises/syllogisms may inspire more confidence in its validity.
Making premises feel meaningful
Making premises meaningful in play requires them to hold a special place relative to other creative sources. In my view, they should at least hold exclusive dominion over those elements they define, which means that you can’t do anything with those elements unless it is through those premises (does it have to be through a syllogism?).
I’m inclined to restrict things further and propose that one should put whatever passes for “plot” or “advancing” the story under the domain of premises (and one other mechanism which I will get into later). This especially means that GM events that would advance the action or potentially have an effect on “plot” would be strictly limited in scope to things covered by premises.
Player Characters vs premises
The only other force that should advance “plot” and action is the Player Character, within the limits imposed by the RPG system of choice. If there is a valid way in which the character can affect the elements covered by the premises, then the Player Character’s action supersedes any established premises for that particular instance of the elements. For example, given the example of cliff dwellings, if the Player Character can through some valid RPG system means destroy that particular dwelling, then he or she can. Otherwise, that destruction can only happen if other premises and/conclusions support it. (One question is, what does “valid RPG system” means signify in this context?)
One thing to consider, is whether the Player Character should have power over the premises themselves. In other words, should the Player Character’s actions be allowed to modify the established premises themselves? This would be akin to world changing changes or discoveries.
Another thing to ponder: Are you always advancing the 'plot'? What are you doing when you're not advancing the plot?
Expanding boundaries set by premises
I only have questions for now.
Other than Player Character action, should there be other ways in which premises can be changed or new premises added? Should there be an "author stance" process that allows the player to do this? If so, what shape should it take? A limited resource economy?
Premises and Baseline Assumptions: Two different palettes?
Given that my preference is for premises to hold exclusive dominion over "plot", my inclination is to view Baseline Assumptions as window dressing (or "color"). A defined procedure would have me using syllogisms to draw the main outline of the next action while colorful details would be filled in using Baseline Assumptions.